https://source.android.com/ 
/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.preference;

import android.annotation.CallSuper;
import android.annotation.DrawableRes;
import android.annotation.LayoutRes;
import android.annotation.Nullable;
import android.annotation.StringRes;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.os.Parcel;
import android.os.Parcelable;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.view.AbsSavedState;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

import com.android.internal.util.CharSequences;

import java.util.ArrayList;
import java.util.List;
import java.util.Set;


Represents the basic Preference UI building block displayed by a PreferenceActivity in the form of a ListView. This class provides the View to be displayed in the activity and associates with a SharedPreferences to store/retrieve the preference data. 
 When specifying a preference hierarchy in XML, each element can point to a subclass of Preference, similar to the view hierarchy and layouts. 
 This class contains a key that will be used as the key into the SharedPreferences. It is up to the subclass to decide how to store the value. 


Developer Guides


For information about building a settings UI with Preferences,
read the Settings
guide.




@attrref android.R.styleable#Preference_icon
@attrref android.R.styleable#Preference_key
@attrref android.R.styleable#Preference_title
@attrref android.R.styleable#Preference_summary
@attrref android.R.styleable#Preference_order
@attrref android.R.styleable#Preference_fragment
@attrref android.R.styleable#Preference_layout
@attrref android.R.styleable#Preference_widgetLayout
@attrref android.R.styleable#Preference_enabled
@attrref android.R.styleable#Preference_selectable
@attrref android.R.styleable#Preference_dependency
@attrref android.R.styleable#Preference_persistent
@attrref android.R.styleable#Preference_defaultValue
@attrref android.R.styleable#Preference_shouldDisableView
@attrref android.R.styleable#Preference_recycleEnabled
@attrref android.R.styleable#Preference_singleLineTitle
@attrref android.R.styleable#Preference_iconSpaceReserved
/**
 * Represents the basic Preference UI building
 * block displayed by a {@link PreferenceActivity} in the form of a
 * {@link ListView}. This class provides the {@link View} to be displayed in
 * the activity and associates with a {@link SharedPreferences} to
 * store/retrieve the preference data.
 * <p>
 * When specifying a preference hierarchy in XML, each element can point to a
 * subclass of {@link Preference}, similar to the view hierarchy and layouts.
 * <p>
 * This class contains a {@code key} that will be used as the key into the
 * {@link SharedPreferences}. It is up to the subclass to decide how to store
 * the value.
 *
 * <div class="special reference">
 * <h3>Developer Guides</h3>
 * <p>For information about building a settings UI with Preferences,
 * read the <a href="{@docRoot}guide/topics/ui/settings.html">Settings</a>
 * guide.</p>
 * </div>
 *
 * @attr ref android.R.styleable#Preference_icon
 * @attr ref android.R.styleable#Preference_key
 * @attr ref android.R.styleable#Preference_title
 * @attr ref android.R.styleable#Preference_summary
 * @attr ref android.R.styleable#Preference_order
 * @attr ref android.R.styleable#Preference_fragment
 * @attr ref android.R.styleable#Preference_layout
 * @attr ref android.R.styleable#Preference_widgetLayout
 * @attr ref android.R.styleable#Preference_enabled
 * @attr ref android.R.styleable#Preference_selectable
 * @attr ref android.R.styleable#Preference_dependency
 * @attr ref android.R.styleable#Preference_persistent
 * @attr ref android.R.styleable#Preference_defaultValue
 * @attr ref android.R.styleable#Preference_shouldDisableView
 * @attr ref android.R.styleable#Preference_recycleEnabled
 * @attr ref android.R.styleable#Preference_singleLineTitle
 * @attr ref android.R.styleable#Preference_iconSpaceReserved
 */
public class Preference implements Comparable<Preference> {
    
Specify for setOrder(int) if a specific order is not required. 
/**
     * Specify for {@link #setOrder(int)} if a specific order is not required.
     */
    public static final int DEFAULT_ORDER = Integer.MAX_VALUE;

    private Context mContext;

    @Nullable
    private PreferenceManager mPreferenceManager;

    
The data store that should be used by this Preference to store / retrieve data. If null then PreferenceManager.getPreferenceDataStore() needs to be checked. If that one is null too it means that we are using SharedPreferences to store the data. 
/**
     * The data store that should be used by this Preference to store / retrieve data. If null then
     * {@link PreferenceManager#getPreferenceDataStore()} needs to be checked. If that one is null
     * too it means that we are using {@link android.content.SharedPreferences} to store the data.
     */
    @Nullable
    private PreferenceDataStore mPreferenceDataStore;

    
Set when added to hierarchy since we need a unique ID within that
hierarchy.

/**
     * Set when added to hierarchy since we need a unique ID within that
     * hierarchy.
     */
    private long mId;

    private OnPreferenceChangeListener mOnChangeListener;
    private OnPreferenceClickListener mOnClickListener;

    private int mOrder = DEFAULT_ORDER;
    private CharSequence mTitle;
    private int mTitleRes;
    private CharSequence mSummary;
    
mIconResId is overridden by mIcon, if mIcon is specified.

/**
     * mIconResId is overridden by mIcon, if mIcon is specified.
     */
    private int mIconResId;
    private Drawable mIcon;
    private String mKey;
    private Intent mIntent;
    private String mFragment;
    private Bundle mExtras;
    private boolean mEnabled = true;
    private boolean mSelectable = true;
    private boolean mRequiresKey;
    private boolean mPersistent = true;
    private String mDependencyKey;
    private Object mDefaultValue;
    private boolean mDependencyMet = true;
    private boolean mParentDependencyMet = true;
    private boolean mRecycleEnabled = true;
    private boolean mHasSingleLineTitleAttr;
    private boolean mSingleLineTitle = true;
    private boolean mIconSpaceReserved;

    
See Also:
  • setShouldDisableView(boolean)
/**
     * @see #setShouldDisableView(boolean)
     */
    private boolean mShouldDisableView = true;

    private int mLayoutResId = com.android.internal.R.layout.preference;
    private int mWidgetLayoutResId;

    private OnPreferenceChangeInternalListener mListener;

    private List<Preference> mDependents;

    private PreferenceGroup mParentGroup;

    private boolean mBaseMethodCalled;

    
Interface definition for a callback to be invoked when the value of this Preference has been changed by the user and is about to be set and/or persisted. This gives the client a chance to prevent setting and/or persisting the value. 
/**
     * Interface definition for a callback to be invoked when the value of this
     * {@link Preference} has been changed by the user and is
     * about to be set and/or persisted.  This gives the client a chance
     * to prevent setting and/or persisting the value.
     */
    public interface OnPreferenceChangeListener {
        
Called when a Preference has been changed by the user. This is
called before the state of the Preference is about to be updated and
before the state is persisted.

Params:
  • preference – The changed Preference.
  • newValue – The new value of the Preference.
Returns:True to update the state of the Preference with the new value.
/**
         * Called when a Preference has been changed by the user. This is
         * called before the state of the Preference is about to be updated and
         * before the state is persisted.
         *
         * @param preference The changed Preference.
         * @param newValue The new value of the Preference.
         * @return True to update the state of the Preference with the new value.
         */
        boolean onPreferenceChange(Preference preference, Object newValue);
    }

    
Interface definition for a callback to be invoked when a Preference is clicked. 
/**
     * Interface definition for a callback to be invoked when a {@link Preference} is
     * clicked.
     */
    public interface OnPreferenceClickListener {
        
Called when a Preference has been clicked.

Params:
  • preference – The Preference that was clicked.
Returns:True if the click was handled.
/**
         * Called when a Preference has been clicked.
         *
         * @param preference The Preference that was clicked.
         * @return True if the click was handled.
         */
        boolean onPreferenceClick(Preference preference);
    }

    
Interface definition for a callback to be invoked when this Preference is changed or, if this is a group, there is an addition/removal of Preference(s). This is used internally. 
/**
     * Interface definition for a callback to be invoked when this
     * {@link Preference} is changed or, if this is a group, there is an
     * addition/removal of {@link Preference}(s). This is used internally.
     */
    interface OnPreferenceChangeInternalListener {
        
Called when this Preference has changed.

Params:
  • preference – This preference.
/**
         * Called when this Preference has changed.
         *
         * @param preference This preference.
         */
        void onPreferenceChange(Preference preference);

        
Called when this group has added/removed Preference(s). 
Params:
  • preference – This Preference.
/**
         * Called when this group has added/removed {@link Preference}(s).
         *
         * @param preference This Preference.
         */
        void onPreferenceHierarchyChange(Preference preference);
    }

    
Perform inflation from XML and apply a class-specific base style. This constructor of Preference allows subclasses to use their own base style when they are inflating. For example, a CheckBoxPreference constructor calls this version of the super class constructor and supplies android.R.attr.checkBoxPreferenceStyle for defStyleAttr. This allows the theme's checkbox preference style to modify all of the base preference attributes as well as the CheckBoxPreference class's attributes. 
Params:
  • context – The Context this is associated with, through which it can access the current theme, resources, SharedPreferences, etc.
  • attrs – The attributes of the XML tag that is inflating the
           preference.
  • defStyleAttr – An attribute in the current theme that contains a
           reference to a style resource that supplies default values for
           the view. Can be 0 to not look for defaults.
  • defStyleRes – A resource identifier of a style resource that
           supplies default values for the view, used only if
           defStyleAttr is 0 or can not be found in the theme. Can be 0
           to not look for defaults.
See Also:
/**
     * Perform inflation from XML and apply a class-specific base style. This
     * constructor of Preference allows subclasses to use their own base style
     * when they are inflating. For example, a {@link CheckBoxPreference}
     * constructor calls this version of the super class constructor and
     * supplies {@code android.R.attr.checkBoxPreferenceStyle} for
     * <var>defStyleAttr</var>. This allows the theme's checkbox preference
     * style to modify all of the base preference attributes as well as the
     * {@link CheckBoxPreference} class's attributes.
     *
     * @param context The Context this is associated with, through which it can
     *            access the current theme, resources,
     *            {@link SharedPreferences}, etc.
     * @param attrs The attributes of the XML tag that is inflating the
     *            preference.
     * @param defStyleAttr An attribute in the current theme that contains a
     *            reference to a style resource that supplies default values for
     *            the view. Can be 0 to not look for defaults.
     * @param defStyleRes A resource identifier of a style resource that
     *            supplies default values for the view, used only if
     *            defStyleAttr is 0 or can not be found in the theme. Can be 0
     *            to not look for defaults.
     * @see #Preference(Context, AttributeSet)
     */
    public Preference(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        mContext = context;

        final TypedArray a = context.obtainStyledAttributes(
                attrs, com.android.internal.R.styleable.Preference, defStyleAttr, defStyleRes);
        for (int i = a.getIndexCount() - 1; i >= 0; i--) {
            int attr = a.getIndex(i);
            switch (attr) {
                case com.android.internal.R.styleable.Preference_icon:
                    mIconResId = a.getResourceId(attr, 0);
                    break;

                case com.android.internal.R.styleable.Preference_key:
                    mKey = a.getString(attr);
                    break;

                case com.android.internal.R.styleable.Preference_title:
                    mTitleRes = a.getResourceId(attr, 0);
                    mTitle = a.getText(attr);
                    break;

                case com.android.internal.R.styleable.Preference_summary:
                    mSummary = a.getText(attr);
                    break;

                case com.android.internal.R.styleable.Preference_order:
                    mOrder = a.getInt(attr, mOrder);
                    break;

                case com.android.internal.R.styleable.Preference_fragment:
                    mFragment = a.getString(attr);
                    break;

                case com.android.internal.R.styleable.Preference_layout:
                    mLayoutResId = a.getResourceId(attr, mLayoutResId);
                    break;

                case com.android.internal.R.styleable.Preference_widgetLayout:
                    mWidgetLayoutResId = a.getResourceId(attr, mWidgetLayoutResId);
                    break;

                case com.android.internal.R.styleable.Preference_enabled:
                    mEnabled = a.getBoolean(attr, true);
                    break;

                case com.android.internal.R.styleable.Preference_selectable:
                    mSelectable = a.getBoolean(attr, true);
                    break;

                case com.android.internal.R.styleable.Preference_persistent:
                    mPersistent = a.getBoolean(attr, mPersistent);
                    break;

                case com.android.internal.R.styleable.Preference_dependency:
                    mDependencyKey = a.getString(attr);
                    break;

                case com.android.internal.R.styleable.Preference_defaultValue:
                    mDefaultValue = onGetDefaultValue(a, attr);
                    break;

                case com.android.internal.R.styleable.Preference_shouldDisableView:
                    mShouldDisableView = a.getBoolean(attr, mShouldDisableView);
                    break;

                case com.android.internal.R.styleable.Preference_recycleEnabled:
                    mRecycleEnabled = a.getBoolean(attr, mRecycleEnabled);
                    break;

                case com.android.internal.R.styleable.Preference_singleLineTitle:
                    mSingleLineTitle = a.getBoolean(attr, mSingleLineTitle);
                    mHasSingleLineTitleAttr = true;
                    break;

                case com.android.internal.R.styleable.Preference_iconSpaceReserved:
                    mIconSpaceReserved = a.getBoolean(attr, mIconSpaceReserved);
                    break;
           }
        }
        a.recycle();
    }

    
Perform inflation from XML and apply a class-specific base style. This constructor of Preference allows subclasses to use their own base style when they are inflating. For example, a CheckBoxPreference constructor calls this version of the super class constructor and supplies android.R.attr.checkBoxPreferenceStyle for defStyleAttr. This allows the theme's checkbox preference style to modify all of the base preference attributes as well as the CheckBoxPreference class's attributes. 
Params:
  • context – The Context this is associated with, through which it can access the current theme, resources, SharedPreferences, etc.
  • attrs – The attributes of the XML tag that is inflating the
           preference.
  • defStyleAttr – An attribute in the current theme that contains a
           reference to a style resource that supplies default values for
           the view. Can be 0 to not look for defaults.
See Also:
/**
     * Perform inflation from XML and apply a class-specific base style. This
     * constructor of Preference allows subclasses to use their own base style
     * when they are inflating. For example, a {@link CheckBoxPreference}
     * constructor calls this version of the super class constructor and
     * supplies {@code android.R.attr.checkBoxPreferenceStyle} for
     * <var>defStyleAttr</var>. This allows the theme's checkbox preference
     * style to modify all of the base preference attributes as well as the
     * {@link CheckBoxPreference} class's attributes.
     *
     * @param context The Context this is associated with, through which it can
     *            access the current theme, resources,
     *            {@link SharedPreferences}, etc.
     * @param attrs The attributes of the XML tag that is inflating the
     *            preference.
     * @param defStyleAttr An attribute in the current theme that contains a
     *            reference to a style resource that supplies default values for
     *            the view. Can be 0 to not look for defaults.
     * @see #Preference(Context, AttributeSet)
     */
    public Preference(Context context, AttributeSet attrs, int defStyleAttr) {
        this(context, attrs, defStyleAttr, 0);
    }

    
Constructor that is called when inflating a Preference from XML. This is
called when a Preference is being constructed from an XML file, supplying
attributes that were specified in the XML file. This version uses a
default style of 0, so the only attribute values applied are those in the
Context's Theme and the given AttributeSet.

Params:
  • context – The Context this is associated with, through which it can access the current theme, resources, SharedPreferences, etc.
  • attrs – The attributes of the XML tag that is inflating the
           preference.
See Also:
/**
     * Constructor that is called when inflating a Preference from XML. This is
     * called when a Preference is being constructed from an XML file, supplying
     * attributes that were specified in the XML file. This version uses a
     * default style of 0, so the only attribute values applied are those in the
     * Context's Theme and the given AttributeSet.
     *
     * @param context The Context this is associated with, through which it can
     *            access the current theme, resources, {@link SharedPreferences},
     *            etc.
     * @param attrs The attributes of the XML tag that is inflating the
     *            preference.
     * @see #Preference(Context, AttributeSet, int)
     */
    public Preference(Context context, AttributeSet attrs) {
        this(context, attrs, com.android.internal.R.attr.preferenceStyle);
    }

    
Constructor to create a Preference.

Params:
  • context – The Context in which to store Preference values.
/**
     * Constructor to create a Preference.
     *
     * @param context The Context in which to store Preference values.
     */
    public Preference(Context context) {
        this(context, null);
    }

    
Called when a Preference is being inflated and the default value
attribute needs to be read. Since different Preference types have
different value types, the subclass should get and return the default
value which will be its value type.

 For example, if the value type is String, the body of the method would proxy to TypedArray.getString(int). 
Params:
  • a – The set of attributes.
  • index – The index of the default value attribute.
Returns:The default value of this preference type.
/**
     * Called when a Preference is being inflated and the default value
     * attribute needs to be read. Since different Preference types have
     * different value types, the subclass should get and return the default
     * value which will be its value type.
     * <p>
     * For example, if the value type is String, the body of the method would
     * proxy to {@link TypedArray#getString(int)}.
     *
     * @param a The set of attributes.
     * @param index The index of the default value attribute.
     * @return The default value of this preference type.
     */
    protected Object onGetDefaultValue(TypedArray a, int index) {
        return null;
    }

    
Sets an Intent to be used for Context.startActivity(Intent) when this Preference is clicked. 
Params:
  • intent – The intent associated with this Preference.
/**
     * Sets an {@link Intent} to be used for
     * {@link Context#startActivity(Intent)} when this Preference is clicked.
     *
     * @param intent The intent associated with this Preference.
     */
    public void setIntent(Intent intent) {
        mIntent = intent;
    }

    
Return the Intent associated with this Preference. 
Returns:The Intent last set via setIntent(Intent) or XML.
/**
     * Return the {@link Intent} associated with this Preference.
     *
     * @return The {@link Intent} last set via {@link #setIntent(Intent)} or XML. 
     */
    public Intent getIntent() {
        return mIntent;
    }

    
Sets the class name of a fragment to be shown when this Preference is clicked.

Params:
  • fragment – The class name of the fragment associated with this Preference.
/**
     * Sets the class name of a fragment to be shown when this Preference is clicked.
     *
     * @param fragment The class name of the fragment associated with this Preference.
     */
    public void setFragment(String fragment) {
        mFragment = fragment;
    }

    
Return the fragment class name associated with this Preference.

Returns:The fragment class name last set via setFragment or XML.
/**
     * Return the fragment class name associated with this Preference.
     *
     * @return The fragment class name last set via {@link #setFragment} or XML.
     */
    public String getFragment() {
        return mFragment;
    }

    
Sets a PreferenceDataStore to be used by this Preference instead of using SharedPreferences. 
The data store will remain assigned even if the Preference is moved around the preference hierarchy. It will also override a data store propagated from the PreferenceManager that owns this Preference. 
Params:
See Also:
/**
     * Sets a {@link PreferenceDataStore} to be used by this Preference instead of using
     * {@link android.content.SharedPreferences}.
     *
     * <p>The data store will remain assigned even if the Preference is moved around the preference
     * hierarchy. It will also override a data store propagated from the {@link PreferenceManager}
     * that owns this Preference.
     *
     * @param dataStore The {@link PreferenceDataStore} to be used by this Preference.
     * @see PreferenceManager#setPreferenceDataStore(PreferenceDataStore)
     */
    public void setPreferenceDataStore(PreferenceDataStore dataStore) {
        mPreferenceDataStore = dataStore;
    }

    
Returns PreferenceDataStore used by this Preference. Returns null if SharedPreferences is used instead. 
By default preferences always use SharedPreferences. To make this preference to use the PreferenceDataStore you need to assign your implementation to the Preference itself via setPreferenceDataStore(PreferenceDataStore) or to its PreferenceManager via PreferenceManager.setPreferenceDataStore(PreferenceDataStore). 
Returns:The PreferenceDataStore used by this Preference or null if none.
/**
     * Returns {@link PreferenceDataStore} used by this Preference. Returns {@code null} if
     * {@link android.content.SharedPreferences} is used instead.
     *
     * <p>By default preferences always use {@link android.content.SharedPreferences}. To make this
     * preference to use the {@link PreferenceDataStore} you need to assign your implementation
     * to the Preference itself via {@link #setPreferenceDataStore(PreferenceDataStore)} or to its
     * {@link PreferenceManager} via
     * {@link PreferenceManager#setPreferenceDataStore(PreferenceDataStore)}.
     *
     * @return The {@link PreferenceDataStore} used by this Preference or {@code null} if none.
     */
    @Nullable
    public PreferenceDataStore getPreferenceDataStore() {
        if (mPreferenceDataStore != null) {
            return mPreferenceDataStore;
        } else if (mPreferenceManager != null) {
            return mPreferenceManager.getPreferenceDataStore();
        }

        return null;
    }

    
Return the extras Bundle object associated with this preference, creating
a new Bundle if there currently isn't one.  You can use this to get and
set individual extra key/value pairs.

/**
     * Return the extras Bundle object associated with this preference, creating
     * a new Bundle if there currently isn't one.  You can use this to get and
     * set individual extra key/value pairs.
     */
    public Bundle getExtras() {
        if (mExtras == null) {
            mExtras = new Bundle();
        }
        return mExtras;
    }

    
Return the extras Bundle object associated with this preference, returning null if there is not currently one. 
/**
     * Return the extras Bundle object associated with this preference, returning {@code null} if
     * there is not currently one.
     */
    public Bundle peekExtras() {
        return mExtras;
    }

    
Sets the layout resource that is inflated as the View to be shown for this Preference. In most cases, the default layout is sufficient for custom Preference objects and only the widget layout needs to be changed. 
 This layout should contain a ViewGroup with ID widget_frame.widget_frame to be the parent of the specific widget for this Preference. It should similarly contain title.title and summary.summary. 
Params:
  • layoutResId – The layout resource ID to be inflated and returned as a View.
See Also:
/**
     * Sets the layout resource that is inflated as the {@link View} to be shown
     * for this Preference. In most cases, the default layout is sufficient for
     * custom Preference objects and only the widget layout needs to be changed.
     * <p>
     * This layout should contain a {@link ViewGroup} with ID
     * {@link android.R.id#widget_frame} to be the parent of the specific widget
     * for this Preference. It should similarly contain
     * {@link android.R.id#title} and {@link android.R.id#summary}.
     *
     * @param layoutResId The layout resource ID to be inflated and returned as
     *            a {@link View}.
     * @see #setWidgetLayoutResource(int)
     */
    public void setLayoutResource(@LayoutRes int layoutResId) {
        if (layoutResId != mLayoutResId) {
            // Layout changed
            mRecycleEnabled = false;
        }

        mLayoutResId = layoutResId;
    }

    
Gets the layout resource that will be shown as the View for this Preference. 
Returns:The layout resource ID.
/**
     * Gets the layout resource that will be shown as the {@link View} for this Preference.
     *
     * @return The layout resource ID.
     */
    @LayoutRes
    public int getLayoutResource() {
        return mLayoutResId;
    }

    
Sets the layout for the controllable widget portion of this Preference. This is inflated into the main layout. For example, a CheckBoxPreference would specify a custom layout (consisting of just the CheckBox) here, instead of creating its own main layout. 
Params:
  • widgetLayoutResId – The layout resource ID to be inflated into the
           main layout.
See Also:
/**
     * Sets the layout for the controllable widget portion of this Preference. This
     * is inflated into the main layout. For example, a {@link CheckBoxPreference}
     * would specify a custom layout (consisting of just the CheckBox) here,
     * instead of creating its own main layout.
     *
     * @param widgetLayoutResId The layout resource ID to be inflated into the
     *            main layout.
     * @see #setLayoutResource(int)
     */
    public void setWidgetLayoutResource(@LayoutRes int widgetLayoutResId) {
        if (widgetLayoutResId != mWidgetLayoutResId) {
            // Layout changed
            mRecycleEnabled = false;
        }
        mWidgetLayoutResId = widgetLayoutResId;
    }

    
Gets the layout resource for the controllable widget portion of this Preference.

Returns:The layout resource ID.
/**
     * Gets the layout resource for the controllable widget portion of this Preference.
     *
     * @return The layout resource ID.
     */
    @LayoutRes
    public int getWidgetLayoutResource() {
        return mWidgetLayoutResId;
    }

    
Gets the View that will be shown in the PreferenceActivity. 
Params:
  • convertView – The old View to reuse, if possible. Note: You should
           check that this View is non-null and of an appropriate type
           before using. If it is not possible to convert this View to
           display the correct data, this method can create a new View.
  • parent – The parent that this View will eventually be attached to.
See Also:
Returns:Returns the same Preference object, for chaining multiple calls
        into a single statement.
/**
     * Gets the View that will be shown in the {@link PreferenceActivity}.
     *
     * @param convertView The old View to reuse, if possible. Note: You should
     *            check that this View is non-null and of an appropriate type
     *            before using. If it is not possible to convert this View to
     *            display the correct data, this method can create a new View.
     * @param parent The parent that this View will eventually be attached to.
     * @return Returns the same Preference object, for chaining multiple calls
     *         into a single statement.
     * @see #onCreateView(ViewGroup)
     * @see #onBindView(View)
     */
    public View getView(View convertView, ViewGroup parent) {
        if (convertView == null) {
            convertView = onCreateView(parent);
        }
        onBindView(convertView);
        return convertView;
    }

    
Creates the View to be shown for this Preference in the PreferenceActivity. The default behavior is to inflate the main layout of this Preference (see setLayoutResource(int). If changing this behavior, please specify a ViewGroup with ID widget_frame.widget_frame. 

Make sure to call through to the superclass's implementation.

Params:
  • parent – The parent that this View will eventually be attached to.
See Also:
Returns:The View that displays this Preference.
/**
     * Creates the View to be shown for this Preference in the
     * {@link PreferenceActivity}. The default behavior is to inflate the main
     * layout of this Preference (see {@link #setLayoutResource(int)}. If
     * changing this behavior, please specify a {@link ViewGroup} with ID
     * {@link android.R.id#widget_frame}.
     * <p>
     * Make sure to call through to the superclass's implementation.
     *
     * @param parent The parent that this View will eventually be attached to.
     * @return The View that displays this Preference.
     * @see #onBindView(View)
     */
    @CallSuper
    protected View onCreateView(ViewGroup parent) {
        final LayoutInflater layoutInflater =
                (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        final View layout = layoutInflater.inflate(mLayoutResId, parent, false);

        final ViewGroup widgetFrame = (ViewGroup) layout
                .findViewById(com.android.internal.R.id.widget_frame);
        if (widgetFrame != null) {
            if (mWidgetLayoutResId != 0) {
                layoutInflater.inflate(mWidgetLayoutResId, widgetFrame);
            } else {
                widgetFrame.setVisibility(View.GONE);
            }
        }
        return layout;
    }

    
Binds the created View to the data for this Preference.


This is a good place to grab references to custom Views in the layout and
set properties on them.


Make sure to call through to the superclass's implementation.

Params:
  • view – The View that shows this Preference.
See Also:
/**
     * Binds the created View to the data for this Preference.
     * <p>
     * This is a good place to grab references to custom Views in the layout and
     * set properties on them.
     * <p>
     * Make sure to call through to the superclass's implementation.
     *
     * @param view The View that shows this Preference.
     * @see #onCreateView(ViewGroup)
     */
    @CallSuper
    protected void onBindView(View view) {
        final TextView titleView = (TextView) view.findViewById(com.android.internal.R.id.title);
        if (titleView != null) {
            final CharSequence title = getTitle();
            if (!TextUtils.isEmpty(title)) {
                titleView.setText(title);
                titleView.setVisibility(View.VISIBLE);
                if (mHasSingleLineTitleAttr) {
                    titleView.setSingleLine(mSingleLineTitle);
                }
            } else {
                titleView.setVisibility(View.GONE);
            }
        }

        final TextView summaryView = (TextView) view.findViewById(
                com.android.internal.R.id.summary);
        if (summaryView != null) {
            final CharSequence summary = getSummary();
            if (!TextUtils.isEmpty(summary)) {
                summaryView.setText(summary);
                summaryView.setVisibility(View.VISIBLE);
            } else {
                summaryView.setVisibility(View.GONE);
            }
        }

        final ImageView imageView = (ImageView) view.findViewById(com.android.internal.R.id.icon);
        if (imageView != null) {
            if (mIconResId != 0 || mIcon != null) {
                if (mIcon == null) {
                    mIcon = getContext().getDrawable(mIconResId);
                }
                if (mIcon != null) {
                    imageView.setImageDrawable(mIcon);
                }
            }
            if (mIcon != null) {
                imageView.setVisibility(View.VISIBLE);
            } else {
                imageView.setVisibility(mIconSpaceReserved ? View.INVISIBLE : View.GONE);
            }
        }

        final View imageFrame = view.findViewById(com.android.internal.R.id.icon_frame);
        if (imageFrame != null) {
            if (mIcon != null) {
                imageFrame.setVisibility(View.VISIBLE);
            } else {
                imageFrame.setVisibility(mIconSpaceReserved ? View.INVISIBLE : View.GONE);
            }
        }

        if (mShouldDisableView) {
            setEnabledStateOnViews(view, isEnabled());
        }
    }

    
Makes sure the view (and any children) get the enabled state changed.

/**
     * Makes sure the view (and any children) get the enabled state changed.
     */
    private void setEnabledStateOnViews(View v, boolean enabled) {
        v.setEnabled(enabled);

        if (v instanceof ViewGroup) {
            final ViewGroup vg = (ViewGroup) v;
            for (int i = vg.getChildCount() - 1; i >= 0; i--) {
                setEnabledStateOnViews(vg.getChildAt(i), enabled);
            }
        }
    }

    
Sets the order of this Preference with respect to other Preference objects on the same level. If this is not specified, the default behavior is to sort alphabetically. The PreferenceGroup.setOrderingAsAdded(boolean) can be used to order Preference objects based on the order they appear in the XML. 
Params:
  • order – the order for this Preference. A lower value will be shown first. Use DEFAULT_ORDER to sort alphabetically or allow ordering from XML
See Also:
/**
     * Sets the order of this Preference with respect to other Preference objects on the same level.
     * If this is not specified, the default behavior is to sort alphabetically. The
     * {@link PreferenceGroup#setOrderingAsAdded(boolean)} can be used to order Preference objects
     * based on the order they appear in the XML.
     *
     * @param order the order for this Preference. A lower value will be shown first. Use
     *              {@link #DEFAULT_ORDER} to sort alphabetically or allow ordering from XML
     * @see PreferenceGroup#setOrderingAsAdded(boolean)
     * @see #DEFAULT_ORDER
     */
    public void setOrder(int order) {
        if (order != mOrder) {
            mOrder = order;

            // Reorder the list
            notifyHierarchyChanged();
        }
    }

    
Gets the order of this Preference with respect to other Preference objects on the same level.

See Also:
Returns:the order of this Preference
/**
     * Gets the order of this Preference with respect to other Preference objects on the same level.
     *
     * @return the order of this Preference
     * @see #setOrder(int)
     */
    public int getOrder() {
        return mOrder;
    }

    
Sets the title for this Preference with a CharSequence. This title will be placed into the ID title.title within the View created by onCreateView(ViewGroup). 
Params:
  • title – the title for this Preference
/**
     * Sets the title for this Preference with a CharSequence. This title will be placed into the ID
     * {@link android.R.id#title} within the View created by {@link #onCreateView(ViewGroup)}.
     *
     * @param title the title for this Preference
     */
    public void setTitle(CharSequence title) {
        if (title == null && mTitle != null || title != null && !title.equals(mTitle)) {
            mTitleRes = 0;
            mTitle = title;
            notifyChanged();
        }
    }

    
Sets the title for this Preference with a resource ID.

Params:
  • titleResId – the title as a resource ID
See Also:
  • setTitle(CharSequence)
/**
     * Sets the title for this Preference with a resource ID.
     *
     * @see #setTitle(CharSequence)
     * @param titleResId the title as a resource ID
     */
    public void setTitle(@StringRes int titleResId) {
        setTitle(mContext.getString(titleResId));
        mTitleRes = titleResId;
    }

    
Returns the title resource ID of this Preference. If the title did not come from a resource, 0 is returned. 
See Also:
Returns:the title resource
/**
     * Returns the title resource ID of this Preference. If the title did not come from a resource,
     * {@code 0} is returned.
     *
     * @return the title resource
     * @see #setTitle(int)
     */
    @StringRes
    public int getTitleRes() {
        return mTitleRes;
    }

    
Returns the title of this Preference.

See Also:
Returns:the title
/**
     * Returns the title of this Preference.
     *
     * @return the title
     * @see #setTitle(CharSequence)
     */
    public CharSequence getTitle() {
        return mTitle;
    }

    
Sets the icon for this Preference with a Drawable. This icon will be placed into the ID icon.icon within the View created by onCreateView(ViewGroup). 
Params:
  • icon – the optional icon for this Preference
/**
     * Sets the icon for this Preference with a Drawable. This icon will be placed into the ID
     * {@link android.R.id#icon} within the View created by {@link #onCreateView(ViewGroup)}.
     *
     * @param icon the optional icon for this Preference
     */
    public void setIcon(Drawable icon) {
        if ((icon == null && mIcon != null) || (icon != null && mIcon != icon)) {
            mIcon = icon;

            notifyChanged();
        }
    }

    
Sets the icon for this Preference with a resource ID.

Params:
  • iconResId – the icon as a resource ID
See Also:
  • setIcon(Drawable)
/**
     * Sets the icon for this Preference with a resource ID.
     *
     * @see #setIcon(Drawable)
     * @param iconResId the icon as a resource ID
     */
    public void setIcon(@DrawableRes int iconResId) {
        if (mIconResId != iconResId) {
            mIconResId = iconResId;
            setIcon(mContext.getDrawable(iconResId));
        }
    }

    
Returns the icon of this Preference.

See Also:
Returns:the icon
/**
     * Returns the icon of this Preference.
     *
     * @return the icon
     * @see #setIcon(Drawable)
     */
    public Drawable getIcon() {
        if (mIcon == null && mIconResId != 0) {
            mIcon = getContext().getDrawable(mIconResId);
        }
        return mIcon;
    }

    
Returns the summary of this Preference.

See Also:
Returns:the summary
/**
     * Returns the summary of this Preference.
     *
     * @return the summary
     * @see #setSummary(CharSequence)
     */
    public CharSequence getSummary() {
        return mSummary;
    }

    
Sets the summary for this Preference with a CharSequence.

Params:
  • summary – the summary for the preference
/**
     * Sets the summary for this Preference with a CharSequence.
     *
     * @param summary the summary for the preference
     */
    public void setSummary(CharSequence summary) {
        if (summary == null && mSummary != null || summary != null && !summary.equals(mSummary)) {
            mSummary = summary;
            notifyChanged();
        }
    }

    
Sets the summary for this Preference with a resource ID.

Params:
  • summaryResId – the summary as a resource
See Also:
  • setSummary(CharSequence)
/**
     * Sets the summary for this Preference with a resource ID.
     *
     * @see #setSummary(CharSequence)
     * @param summaryResId the summary as a resource
     */
    public void setSummary(@StringRes int summaryResId) {
        setSummary(mContext.getString(summaryResId));
    }

    
Sets whether this Preference is enabled. If disabled, it will
not handle clicks.

Params:
  • enabled – set true to enable it
/**
     * Sets whether this Preference is enabled. If disabled, it will
     * not handle clicks.
     *
     * @param enabled set {@code true} to enable it
     */
    public void setEnabled(boolean enabled) {
        if (mEnabled != enabled) {
            mEnabled = enabled;

            // Enabled state can change dependent preferences' states, so notify
            notifyDependencyChange(shouldDisableDependents());

            notifyChanged();
        }
    }

    
Checks whether this Preference should be enabled in the list.

Returns:true if this Preference is enabled, false otherwise
/**
     * Checks whether this Preference should be enabled in the list.
     *
     * @return {@code true} if this Preference is enabled, false otherwise
     */
    public boolean isEnabled() {
        return mEnabled && mDependencyMet && mParentDependencyMet;
    }

    
Sets whether this Preference is selectable.

Params:
  • selectable – set true to make it selectable
/**
     * Sets whether this Preference is selectable.
     *
     * @param selectable set {@code true} to make it selectable
     */
    public void setSelectable(boolean selectable) {
        if (mSelectable != selectable) {
            mSelectable = selectable;
            notifyChanged();
        }
    }

    
Checks whether this Preference should be selectable in the list.

Returns:true if it is selectable, false otherwise
/**
     * Checks whether this Preference should be selectable in the list.
     *
     * @return {@code true} if it is selectable, {@code false} otherwise
     */
    public boolean isSelectable() {
        return mSelectable;
    }

    
Sets whether this Preference should disable its view when it gets disabled.

For example, set this and setEnabled(boolean) to false for preferences that are only displaying information and 1) should not be clickable 2) should not have the view set to the disabled state. 
Params:
  • shouldDisableView – set true if this preference should disable its view when the preference is disabled
/**
     * Sets whether this Preference should disable its view when it gets disabled.
     *
     * <p>For example, set this and {@link #setEnabled(boolean)} to false for preferences that are
     * only displaying information and 1) should not be clickable 2) should not have the view set to
     * the disabled state.
     *
     * @param shouldDisableView set {@code true} if this preference should disable its view when
     *                          the preference is disabled
     */
    public void setShouldDisableView(boolean shouldDisableView) {
        mShouldDisableView = shouldDisableView;
        notifyChanged();
    }

    
Checks whether this Preference should disable its view when it's action is disabled.

See Also:
  • setShouldDisableView(boolean)
Returns:true if it should disable the view
/**
     * Checks whether this Preference should disable its view when it's action is disabled.
     *
     * @see #setShouldDisableView(boolean)
     * @return {@code true} if it should disable the view
     */
    public boolean getShouldDisableView() {
        return mShouldDisableView;
    }

    
Sets whether this Preference has enabled to have its view recycled when used in the list
view. By default the recycling is enabled.

The value can be changed only before this preference is added to the preference hierarchy.

If view recycling is not allowed then each time the list view populates this preference the getView(View, ViewGroup) method receives a null convert view and needs to recreate the view. Otherwise view gets recycled and only onBindView(View) gets called. 
Params:
  • enabled – set true if this preference view should be recycled
/**
     * Sets whether this Preference has enabled to have its view recycled when used in the list
     * view. By default the recycling is enabled.
     *
     * <p>The value can be changed only before this preference is added to the preference hierarchy.
     *
     * <p>If view recycling is not allowed then each time the list view populates this preference
     * the {@link #getView(View, ViewGroup)} method receives a {@code null} convert view and needs
     * to recreate the view. Otherwise view gets recycled and only {@link #onBindView(View)} gets
     * called.
     *
     * @param enabled set {@code true} if this preference view should be recycled
     */
    @CallSuper
    public void setRecycleEnabled(boolean enabled) {
        mRecycleEnabled = enabled;
        notifyChanged();
    }

    
Checks whether this Preference has enabled to have its view recycled when used in the list
view.

See Also:
  • setRecycleEnabled(boolean)
Returns:true if this preference view should be recycled
/**
     * Checks whether this Preference has enabled to have its view recycled when used in the list
     * view.
     *
     * @see #setRecycleEnabled(boolean)
     * @return {@code true} if this preference view should be recycled
     */
    public boolean isRecycleEnabled() {
        return mRecycleEnabled;
    }

    
Sets whether to constrain the title of this Preference to a single line instead of
letting it wrap onto multiple lines.

Params:
  • singleLineTitle – set true if the title should be constrained to one line
/**
     * Sets whether to constrain the title of this Preference to a single line instead of
     * letting it wrap onto multiple lines.
     *
     * @param singleLineTitle set {@code true} if the title should be constrained to one line
     */
    public void setSingleLineTitle(boolean singleLineTitle) {
        mHasSingleLineTitleAttr = true;
        mSingleLineTitle = singleLineTitle;
        notifyChanged();
    }

    
Gets whether the title of this preference is constrained to a single line.

See Also:
  • setSingleLineTitle(boolean)
Returns:true if the title of this preference is constrained to a single line
/**
     * Gets whether the title of this preference is constrained to a single line.
     *
     * @see #setSingleLineTitle(boolean)
     * @return {@code true} if the title of this preference is constrained to a single line
     */
    public boolean isSingleLineTitle() {
        return mSingleLineTitle;
    }

    
Sets whether to reserve the space of this Preference icon view when no icon is provided.

Params:
  • iconSpaceReserved – set true if the space for the icon view should be reserved
/**
     * Sets whether to reserve the space of this Preference icon view when no icon is provided.
     *
     * @param iconSpaceReserved set {@code true} if the space for the icon view should be reserved
     */
    public void setIconSpaceReserved(boolean iconSpaceReserved) {
        mIconSpaceReserved = iconSpaceReserved;
        notifyChanged();
    }

    
Gets whether the space this preference icon view is reserved.

See Also:
  • setIconSpaceReserved(boolean)
Returns:true if the space of this preference icon view is reserved
/**
     * Gets whether the space this preference icon view is reserved.
     *
     * @see #setIconSpaceReserved(boolean)
     * @return {@code true} if the space of this preference icon view is reserved
     */
    public boolean isIconSpaceReserved() {
        return mIconSpaceReserved;
    }
    
Returns a unique ID for this Preference.  This ID should be unique across all
Preference objects in a hierarchy.

Returns:A unique ID for this Preference.
/**
     * Returns a unique ID for this Preference.  This ID should be unique across all
     * Preference objects in a hierarchy.
     *
     * @return A unique ID for this Preference.
     */
    long getId() {
        return mId;
    }

    
Processes a click on the preference. This includes saving the value to the SharedPreferences. However, the overridden method should call callChangeListener(Object) to make sure the client wants to update the preference's state with the new value. 
/**
     * Processes a click on the preference. This includes saving the value to
     * the {@link SharedPreferences}. However, the overridden method should
     * call {@link #callChangeListener(Object)} to make sure the client wants to
     * update the preference's state with the new value.
     */
    protected void onClick() {
    }

    
Sets the key for this Preference, which is used as a key to the SharedPreferences or PreferenceDataStore. This should be unique for the package. 
Params:
  • key – The key for the preference.
/**
     * Sets the key for this Preference, which is used as a key to the {@link SharedPreferences} or
     * {@link PreferenceDataStore}. This should be unique for the package.
     *
     * @param key The key for the preference.
     */
    public void setKey(String key) {
        mKey = key;

        if (mRequiresKey && !hasKey()) {
            requireKey();
        }
    }

    
Gets the key for this Preference, which is also the key used for storing values into SharedPreferences or PreferenceDataStore. 
Returns:The key.
/**
     * Gets the key for this Preference, which is also the key used for storing values into
     * {@link SharedPreferences} or {@link PreferenceDataStore}.
     *
     * @return The key.
     */
    public String getKey() {
        return mKey;
    }

    
Checks whether the key is present, and if it isn't throws an
exception. This should be called by subclasses that persist their preferences.

Throws:
  • IllegalStateException – If there is no key assigned.
/**
     * Checks whether the key is present, and if it isn't throws an
     * exception. This should be called by subclasses that persist their preferences.
     *
     * @throws IllegalStateException If there is no key assigned.
     */
    void requireKey() {
        if (mKey == null) {
            throw new IllegalStateException("Preference does not have a key assigned.");
        }

        mRequiresKey = true;
    }

    
Checks whether this Preference has a valid key.

Returns:True if the key exists and is not a blank string, false otherwise.
/**
     * Checks whether this Preference has a valid key.
     *
     * @return True if the key exists and is not a blank string, false otherwise.
     */
    public boolean hasKey() {
        return !TextUtils.isEmpty(mKey);
    }

    
Checks whether this Preference is persistent. If it is, it stores its value(s) into the persistent SharedPreferences storage by default or into PreferenceDataStore if assigned. 
Returns:True if it is persistent.
/**
     * Checks whether this Preference is persistent. If it is, it stores its value(s) into
     * the persistent {@link SharedPreferences} storage by default or into
     * {@link PreferenceDataStore} if assigned.
     *
     * @return True if it is persistent.
     */
    public boolean isPersistent() {
        return mPersistent;
    }

    
Checks whether, at the given time this method is called, this Preference should store/restore its value(s) into the SharedPreferences or into PreferenceDataStore if assigned. This, at minimum, checks whether this Preference is persistent and it currently has a key. Before you save/restore from the storage, check this first. 
Returns:True if it should persist the value.
/**
     * Checks whether, at the given time this method is called, this Preference should store/restore
     * its value(s) into the {@link SharedPreferences} or into {@link PreferenceDataStore} if
     * assigned. This, at minimum, checks whether this Preference is persistent and it currently has
     * a key. Before you save/restore from the storage, check this first.
     *
     * @return True if it should persist the value.
     */
    protected boolean shouldPersist() {
        return mPreferenceManager != null && isPersistent() && hasKey();
    }

    
Sets whether this Preference is persistent. When persistent, it stores its value(s) into the persistent SharedPreferences storage by default or into PreferenceDataStore if assigned. 
Params:
  • persistent – set true if it should store its value(s) into the storage.
/**
     * Sets whether this Preference is persistent. When persistent, it stores its value(s) into
     * the persistent {@link SharedPreferences} storage by default or into
     * {@link PreferenceDataStore} if assigned.
     *
     * @param persistent set {@code true} if it should store its value(s) into the storage.
     */
    public void setPersistent(boolean persistent) {
        mPersistent = persistent;
    }

    
Call this method after the user changes the preference, but before the
internal state is set. This allows the client to ignore the user value.

Params:
  • newValue – The new value of this Preference.
Returns:True if the user value should be set as the preference
        value (and persisted).
/**
     * Call this method after the user changes the preference, but before the
     * internal state is set. This allows the client to ignore the user value.
     *
     * @param newValue The new value of this Preference.
     * @return True if the user value should be set as the preference
     *         value (and persisted).
     */
    protected boolean callChangeListener(Object newValue) {
        return mOnChangeListener == null || mOnChangeListener.onPreferenceChange(this, newValue);
    }

    
Sets the callback to be invoked when this Preference is changed by the
user (but before the internal state has been updated).

Params:
  • onPreferenceChangeListener – The callback to be invoked.
/**
     * Sets the callback to be invoked when this Preference is changed by the
     * user (but before the internal state has been updated).
     *
     * @param onPreferenceChangeListener The callback to be invoked.
     */
    public void setOnPreferenceChangeListener(OnPreferenceChangeListener onPreferenceChangeListener) {
        mOnChangeListener = onPreferenceChangeListener;
    }

    
Returns the callback to be invoked when this Preference is changed by the
user (but before the internal state has been updated).

Returns:The callback to be invoked.
/**
     * Returns the callback to be invoked when this Preference is changed by the
     * user (but before the internal state has been updated).
     *
     * @return The callback to be invoked.
     */
    public OnPreferenceChangeListener getOnPreferenceChangeListener() {
        return mOnChangeListener;
    }

    
Sets the callback to be invoked when this Preference is clicked.

Params:
  • onPreferenceClickListener – The callback to be invoked.
/**
     * Sets the callback to be invoked when this Preference is clicked.
     *
     * @param onPreferenceClickListener The callback to be invoked.
     */
    public void setOnPreferenceClickListener(OnPreferenceClickListener onPreferenceClickListener) {
        mOnClickListener = onPreferenceClickListener;
    }

    
Returns the callback to be invoked when this Preference is clicked.

Returns:The callback to be invoked.
/**
     * Returns the callback to be invoked when this Preference is clicked.
     *
     * @return The callback to be invoked.
     */
    public OnPreferenceClickListener getOnPreferenceClickListener() {
        return mOnClickListener;
    }

    
Called when a click should be performed.

Params:
  • preferenceScreen – A PreferenceScreen whose hierarchy click listener should be called in the proper order (between other processing). May be null.
@hide
/**
     * Called when a click should be performed.
     *
     * @param preferenceScreen A {@link PreferenceScreen} whose hierarchy click
     *            listener should be called in the proper order (between other
     *            processing). May be {@code null}.
     * @hide
     */
    public void performClick(PreferenceScreen preferenceScreen) {

        if (!isEnabled()) {
            return;
        }

        onClick();

        if (mOnClickListener != null && mOnClickListener.onPreferenceClick(this)) {
            return;
        }

        PreferenceManager preferenceManager = getPreferenceManager();
        if (preferenceManager != null) {
            PreferenceManager.OnPreferenceTreeClickListener listener = preferenceManager
                    .getOnPreferenceTreeClickListener();
            if (preferenceScreen != null && listener != null
                    && listener.onPreferenceTreeClick(preferenceScreen, this)) {
                return;
            }
        }

        if (mIntent != null) {
            Context context = getContext();
            context.startActivity(mIntent);
        }
    }

    
Allows a Preference to intercept key events without having focus.
For example, SeekBarPreference uses this to intercept +/- to adjust
the progress.

Returns:True if the Preference handled the key. Returns false by default.
@hide
/**
     * Allows a Preference to intercept key events without having focus.
     * For example, SeekBarPreference uses this to intercept +/- to adjust
     * the progress.
     * @return True if the Preference handled the key. Returns false by default.
     * @hide
     */
    public boolean onKey(View v, int keyCode, KeyEvent event) {
        return false;
    }

    
Returns the Context of this Preference. Each Preference in a Preference hierarchy can be from different Context (for example, if multiple activities provide preferences into a single PreferenceActivity). This Context will be used to save the Preference values. 
Returns:The Context of this Preference.
/**
     * Returns the {@link android.content.Context} of this Preference.
     * Each Preference in a Preference hierarchy can be
     * from different Context (for example, if multiple activities provide preferences into a single
     * {@link PreferenceActivity}). This Context will be used to save the Preference values.
     *
     * @return The Context of this Preference.
     */
    public Context getContext() {
        return mContext;
    }

    
Returns the SharedPreferences where this Preference can read its value(s). Usually, it's easier to use one of the helper read methods: getPersistedBoolean(boolean), getPersistedFloat(float), getPersistedInt(int), getPersistedLong(long), getPersistedString(String). To save values, see getEditor(). 
 In some cases, writes to the getEditor() will not be committed right away and hence not show up in the returned SharedPreferences, this is intended behavior to improve performance. 
See Also:
Returns:the SharedPreferences where this Preference reads its value(s). If this preference isn't attached to a Preference hierarchy or if a PreferenceDataStore has been set, this method returns null.
/**
     * Returns the {@link SharedPreferences} where this Preference can read its
     * value(s). Usually, it's easier to use one of the helper read methods:
     * {@link #getPersistedBoolean(boolean)}, {@link #getPersistedFloat(float)},
     * {@link #getPersistedInt(int)}, {@link #getPersistedLong(long)},
     * {@link #getPersistedString(String)}. To save values, see
     * {@link #getEditor()}.
     * <p>
     * In some cases, writes to the {@link #getEditor()} will not be committed
     * right away and hence not show up in the returned
     * {@link SharedPreferences}, this is intended behavior to improve
     * performance.
     *
     * @return the {@link SharedPreferences} where this Preference reads its value(s). If
     *         this preference isn't attached to a Preference hierarchy or if
     *         a {@link PreferenceDataStore} has been set, this method returns {@code null}.
     * @see #getEditor()
     * @see #setPreferenceDataStore(PreferenceDataStore)
     */
    public SharedPreferences getSharedPreferences() {
        if (mPreferenceManager == null || getPreferenceDataStore() != null) {
            return null;
        }

        return mPreferenceManager.getSharedPreferences();
    }

    
Returns an Editor where this Preference can save its value(s). Usually it's easier to use one of the helper save methods: persistBoolean(boolean), persistFloat(float), persistInt(int), persistLong(long), persistString(String). To read values, see getSharedPreferences(). If shouldCommit() returns true, it is this Preference's responsibility to commit. 

In some cases, writes to this will not be committed right away and hence
not show up in the SharedPreferences, this is intended behavior to
improve performance.

See Also:
Returns:a Editor where this preference saves its value(s). If this preference isn't attached to a Preference hierarchy or if a PreferenceDataStore has been set, this method returns null.
/**
     * Returns an {@link SharedPreferences.Editor} where this Preference can
     * save its value(s). Usually it's easier to use one of the helper save
     * methods: {@link #persistBoolean(boolean)}, {@link #persistFloat(float)},
     * {@link #persistInt(int)}, {@link #persistLong(long)},
     * {@link #persistString(String)}. To read values, see
     * {@link #getSharedPreferences()}. If {@link #shouldCommit()} returns
     * true, it is this Preference's responsibility to commit.
     * <p>
     * In some cases, writes to this will not be committed right away and hence
     * not show up in the SharedPreferences, this is intended behavior to
     * improve performance.
     *
     * @return a {@link SharedPreferences.Editor} where this preference saves its value(s). If
     *         this preference isn't attached to a Preference hierarchy or if
     *         a {@link PreferenceDataStore} has been set, this method returns {@code null}.
     * @see #shouldCommit()
     * @see #getSharedPreferences()
     * @see #setPreferenceDataStore(PreferenceDataStore)
     */
    public SharedPreferences.Editor getEditor() {
        if (mPreferenceManager == null || getPreferenceDataStore() != null) {
            return null;
        }

        return mPreferenceManager.getEditor();
    }

    
Returns whether the Preference should commit its saved value(s) in getEditor(). This may return false in situations where batch committing is being done (by the manager) to improve performance. 
If this preference is using PreferenceDataStore this value is irrelevant. 
See Also:
Returns:Whether the Preference should commit its saved value(s).
/**
     * Returns whether the {@link Preference} should commit its saved value(s) in
     * {@link #getEditor()}. This may return false in situations where batch
     * committing is being done (by the manager) to improve performance.
     *
     * <p>If this preference is using {@link PreferenceDataStore} this value is irrelevant.
     *
     * @return Whether the Preference should commit its saved value(s).
     * @see #getEditor()
     */
    public boolean shouldCommit() {
        if (mPreferenceManager == null) {
            return false;
        }

        return mPreferenceManager.shouldCommit();
    }

    
Compares Preference objects based on order (if set), otherwise alphabetically on the titles.

Params:
  • another – The Preference to compare to this one.
Returns:0 if the same; less than 0 if this Preference sorts ahead of another;
         greater than 0 if this Preference sorts after another.
/**
     * Compares Preference objects based on order (if set), otherwise alphabetically on the titles.
     *
     * @param another The Preference to compare to this one.
     * @return 0 if the same; less than 0 if this Preference sorts ahead of <var>another</var>;
     *          greater than 0 if this Preference sorts after <var>another</var>.
     */
    @Override
    public int compareTo(Preference another) {
        if (mOrder != another.mOrder) {
            // Do order comparison
            return mOrder - another.mOrder;
        } else if (mTitle == another.mTitle) {
            // If titles are null or share same object comparison
            return 0;
        } else if (mTitle == null) {
            return 1;
        } else if (another.mTitle == null) {
            return -1;
        } else {
            // Do name comparison
            return CharSequences.compareToIgnoreCase(mTitle, another.mTitle);
        }
    }

    
Sets the internal change listener.

Params:
  • listener – The listener.
See Also:
/**
     * Sets the internal change listener.
     *
     * @param listener The listener.
     * @see #notifyChanged()
     */
    final void setOnPreferenceChangeInternalListener(OnPreferenceChangeInternalListener listener) {
        mListener = listener;
    }

    
Should be called when the data of this Preference has changed. 
/**
     * Should be called when the data of this {@link Preference} has changed.
     */
    protected void notifyChanged() {
        if (mListener != null) {
            mListener.onPreferenceChange(this);
        }
    }

    
Should be called when a Preference has been
added/removed from this group, or the ordering should be
re-evaluated.

/**
     * Should be called when a Preference has been
     * added/removed from this group, or the ordering should be
     * re-evaluated.
     */
    protected void notifyHierarchyChanged() {
        if (mListener != null) {
            mListener.onPreferenceHierarchyChange(this);
        }
    }

    
Gets the PreferenceManager that manages this Preference object's tree. 
Returns:The PreferenceManager.
/**
     * Gets the {@link PreferenceManager} that manages this Preference object's tree.
     *
     * @return The {@link PreferenceManager}.
     */
    public PreferenceManager getPreferenceManager() {
        return mPreferenceManager;
    }

    
Called when this Preference has been attached to a Preference hierarchy.
Make sure to call the super implementation.

Params:
  • preferenceManager – The PreferenceManager of the hierarchy.
/**
     * Called when this Preference has been attached to a Preference hierarchy.
     * Make sure to call the super implementation.
     *
     * @param preferenceManager The PreferenceManager of the hierarchy.
     */
    protected void onAttachedToHierarchy(PreferenceManager preferenceManager) {
        mPreferenceManager = preferenceManager;

        mId = preferenceManager.getNextId();

        dispatchSetInitialValue();
    }

    
Called when the Preference hierarchy has been attached to the PreferenceActivity. This can also be called when this Preference has been attached to a group that was already attached to the PreferenceActivity. 
/**
     * Called when the Preference hierarchy has been attached to the
     * {@link PreferenceActivity}. This can also be called when this
     * Preference has been attached to a group that was already attached
     * to the {@link PreferenceActivity}.
     */
    protected void onAttachedToActivity() {
        // At this point, the hierarchy that this preference is in is connected
        // with all other preferences.
        registerDependency();
    }

    
Assigns a PreferenceGroup as the parent of this Preference. Set null to remove the current parent. 
Params:
  • parentGroup – Parent preference group of this Preference or null if none.
/**
     * Assigns a {@link PreferenceGroup} as the parent of this Preference. Set {@code null} to
     * remove the current parent.
     *
     * @param parentGroup Parent preference group of this Preference or {@code null} if none.
     */
    void assignParent(@Nullable PreferenceGroup parentGroup) {
        mParentGroup = parentGroup;
    }

    private void registerDependency() {

        if (TextUtils.isEmpty(mDependencyKey)) return;

        Preference preference = findPreferenceInHierarchy(mDependencyKey);
        if (preference != null) {
            preference.registerDependent(this);
        } else {
            throw new IllegalStateException("Dependency \"" + mDependencyKey
                    + "\" not found for preference \"" + mKey + "\" (title: \"" + mTitle + "\"");
        }
    }

    private void unregisterDependency() {
        if (mDependencyKey != null) {
            final Preference oldDependency = findPreferenceInHierarchy(mDependencyKey);
            if (oldDependency != null) {
                oldDependency.unregisterDependent(this);
            }
        }
    }

    
Finds a Preference in this hierarchy (the whole thing, even above/below your PreferenceScreen screen break) with the given key. 

This only functions after we have been attached to a hierarchy.

Params:
  • key – The key of the Preference to find.
Returns:The Preference that uses the given key.
/**
     * Finds a Preference in this hierarchy (the whole thing,
     * even above/below your {@link PreferenceScreen} screen break) with the given
     * key.
     * <p>
     * This only functions after we have been attached to a hierarchy.
     *
     * @param key The key of the Preference to find.
     * @return The Preference that uses the given key.
     */
    protected Preference findPreferenceInHierarchy(String key) {
        if (TextUtils.isEmpty(key) || mPreferenceManager == null) {
            return null;
        }

        return mPreferenceManager.findPreference(key);
    }

    
Adds a dependent Preference on this Preference so we can notify it. Usually, the dependent Preference registers itself (it's good for it to know it depends on something), so please use setDependency(String) on the dependent Preference. 
Params:
  • dependent – The dependent Preference that will be enabled/disabled
           according to the state of this Preference.
/**
     * Adds a dependent Preference on this Preference so we can notify it.
     * Usually, the dependent Preference registers itself (it's good for it to
     * know it depends on something), so please use
     * {@link Preference#setDependency(String)} on the dependent Preference.
     *
     * @param dependent The dependent Preference that will be enabled/disabled
     *            according to the state of this Preference.
     */
    private void registerDependent(Preference dependent) {
        if (mDependents == null) {
            mDependents = new ArrayList<Preference>();
        }

        mDependents.add(dependent);

        dependent.onDependencyChanged(this, shouldDisableDependents());
    }

    
Removes a dependent Preference on this Preference.

Params:
  • dependent – The dependent Preference that will be enabled/disabled
           according to the state of this Preference.
Returns:Returns the same Preference object, for chaining multiple calls
        into a single statement.
/**
     * Removes a dependent Preference on this Preference.
     *
     * @param dependent The dependent Preference that will be enabled/disabled
     *            according to the state of this Preference.
     * @return Returns the same Preference object, for chaining multiple calls
     *         into a single statement.
     */
    private void unregisterDependent(Preference dependent) {
        if (mDependents != null) {
            mDependents.remove(dependent);
        }
    }

    
Notifies any listening dependents of a change that affects the
dependency.

Params:
  • disableDependents – Whether this Preference should disable
           its dependents.
/**
     * Notifies any listening dependents of a change that affects the
     * dependency.
     *
     * @param disableDependents Whether this Preference should disable
     *            its dependents.
     */
    public void notifyDependencyChange(boolean disableDependents) {
        final List<Preference> dependents = mDependents;

        if (dependents == null) {
            return;
        }

        final int dependentsCount = dependents.size();
        for (int i = 0; i < dependentsCount; i++) {
            dependents.get(i).onDependencyChanged(this, disableDependents);
        }
    }

    
Called when the dependency changes.

Params:
  • dependency – The Preference that this Preference depends on.
  • disableDependent – Set true to disable this Preference.
/**
     * Called when the dependency changes.
     *
     * @param dependency The Preference that this Preference depends on.
     * @param disableDependent Set true to disable this Preference.
     */
    public void onDependencyChanged(Preference dependency, boolean disableDependent) {
        if (mDependencyMet == disableDependent) {
            mDependencyMet = !disableDependent;

            // Enabled state can change dependent preferences' states, so notify
            notifyDependencyChange(shouldDisableDependents());

            notifyChanged();
        }
    }

    
Called when the implicit parent dependency changes.

Params:
  • parent – The Preference that this Preference depends on.
  • disableChild – Set true to disable this Preference.
/**
     * Called when the implicit parent dependency changes.
     *
     * @param parent The Preference that this Preference depends on.
     * @param disableChild Set true to disable this Preference.
     */
    public void onParentChanged(Preference parent, boolean disableChild) {
        if (mParentDependencyMet == disableChild) {
            mParentDependencyMet = !disableChild;

            // Enabled state can change dependent preferences' states, so notify
            notifyDependencyChange(shouldDisableDependents());

            notifyChanged();
        }
    }

    
Checks whether this preference's dependents should currently be
disabled.

Returns:True if the dependents should be disabled, otherwise false.
/**
     * Checks whether this preference's dependents should currently be
     * disabled.
     *
     * @return True if the dependents should be disabled, otherwise false.
     */
    public boolean shouldDisableDependents() {
        return !isEnabled();
    }

    
Sets the key of a Preference that this Preference will depend on. If that
Preference is not set or is off, this Preference will be disabled.

Params:
  • dependencyKey – The key of the Preference that this depends on.
/**
     * Sets the key of a Preference that this Preference will depend on. If that
     * Preference is not set or is off, this Preference will be disabled.
     *
     * @param dependencyKey The key of the Preference that this depends on.
     */
    public void setDependency(String dependencyKey) {
        // Unregister the old dependency, if we had one
        unregisterDependency();

        // Register the new
        mDependencyKey = dependencyKey;
        registerDependency();
    }

    
Returns the key of the dependency on this Preference.

See Also:
Returns:The key of the dependency.
/**
     * Returns the key of the dependency on this Preference.
     *
     * @return The key of the dependency.
     * @see #setDependency(String)
     */
    public String getDependency() {
        return mDependencyKey;
    }

    
Returns the PreferenceGroup which is this Preference assigned to or null if this preference is not assigned to any group or is a root Preference. 
Returns:the parent PreferenceGroup or null if not attached to any
/**
     * Returns the {@link PreferenceGroup} which is this Preference assigned to or {@code null} if
     * this preference is not assigned to any group or is a root Preference.
     *
     * @return the parent PreferenceGroup or {@code null} if not attached to any
     */
    @Nullable
    public PreferenceGroup getParent() {
        return mParentGroup;
    }

    
Called when this Preference is being removed from the hierarchy. You
should remove any references to this Preference that you know about. Make
sure to call through to the superclass implementation.

/**
     * Called when this Preference is being removed from the hierarchy. You
     * should remove any references to this Preference that you know about. Make
     * sure to call through to the superclass implementation.
     */
    @CallSuper
    protected void onPrepareForRemoval() {
        unregisterDependency();
    }

    
Sets the default value for this Preference, which will be set either if
persistence is off or persistence is on and the preference is not found
in the persistent storage.

Params:
  • defaultValue – The default value.
/**
     * Sets the default value for this Preference, which will be set either if
     * persistence is off or persistence is on and the preference is not found
     * in the persistent storage.
     *
     * @param defaultValue The default value.
     */
    public void setDefaultValue(Object defaultValue) {
        mDefaultValue = defaultValue;
    }

    private void dispatchSetInitialValue() {
        if (getPreferenceDataStore() != null) {
            onSetInitialValue(true, mDefaultValue);
            return;
        }

        // By now, we know if we are persistent.
        final boolean shouldPersist = shouldPersist();
        if (!shouldPersist || !getSharedPreferences().contains(mKey)) {
            if (mDefaultValue != null) {
                onSetInitialValue(false, mDefaultValue);
            }
        } else {
            onSetInitialValue(true, null);
        }
    }

    
Implement this to set the initial value of the Preference.

If restorePersistedValue is true, you should restore the Preference value from the SharedPreferences. If restorePersistedValue is false, you should set the Preference value to defaultValue that is given (and possibly store to SharedPreferences if shouldPersist() is true). 
In case of using PreferenceDataStore, the restorePersistedValue is always true. But the default value (if provided) is set. 
This may not always be called. One example is if it should not persist
but there is no default value given.

Params:
  • restorePersistedValue – True to restore the persisted value;
           false to use the given defaultValue.
  • defaultValue – The default value for this Preference. Only use this
           if restorePersistedValue is false.
/**
     * Implement this to set the initial value of the Preference.
     *
     * <p>If <var>restorePersistedValue</var> is true, you should restore the
     * Preference value from the {@link android.content.SharedPreferences}. If
     * <var>restorePersistedValue</var> is false, you should set the Preference
     * value to defaultValue that is given (and possibly store to SharedPreferences
     * if {@link #shouldPersist()} is true).
     *
     * <p>In case of using {@link PreferenceDataStore}, the <var>restorePersistedValue</var> is
     * always {@code true}. But the default value (if provided) is set.
     *
     * <p>This may not always be called. One example is if it should not persist
     * but there is no default value given.
     *
     * @param restorePersistedValue True to restore the persisted value;
     *            false to use the given <var>defaultValue</var>.
     * @param defaultValue The default value for this Preference. Only use this
     *            if <var>restorePersistedValue</var> is false.
     */
    protected void onSetInitialValue(boolean restorePersistedValue, Object defaultValue) {
    }

    private void tryCommit(SharedPreferences.Editor editor) {
        if (mPreferenceManager.shouldCommit()) {
            try {
                editor.apply();
            } catch (AbstractMethodError unused) {
                // The app injected its own pre-Gingerbread
                // SharedPreferences.Editor implementation without
                // an apply method.
                editor.commit();
            }
        }
    }

    
Attempts to persist a String if this Preference is persistent.

Params:
  • value – The value to persist.
See Also:
Returns:True if this Preference is persistent. (This is not whether the
        value was persisted, since we may not necessarily commit if there
        will be a batch commit later.)
/**
     * Attempts to persist a String if this Preference is persistent.
     *
     * @param value The value to persist.
     * @return True if this Preference is persistent. (This is not whether the
     *         value was persisted, since we may not necessarily commit if there
     *         will be a batch commit later.)
     * @see #getPersistedString(String)
     */
    protected boolean persistString(String value) {
        if (!shouldPersist()) {
            return false;
        }

        // Shouldn't store null
        if (TextUtils.equals(value, getPersistedString(null))) {
            // It's already there, so the same as persisting
            return true;
        }

        PreferenceDataStore dataStore = getPreferenceDataStore();
        if (dataStore != null) {
            dataStore.putString(mKey, value);
        } else {
            SharedPreferences.Editor editor = mPreferenceManager.getEditor();
            editor.putString(mKey, value);
            tryCommit(editor);
        }
        return true;
    }

    
Attempts to get a persisted String if this Preference is persistent.

Params:
  • defaultReturnValue – The default value to return if either this
           Preference is not persistent or this Preference is not present.
See Also:
Returns:The value from the data store or the default return
        value.
/**
     * Attempts to get a persisted String if this Preference is persistent.
     *
     * @param defaultReturnValue The default value to return if either this
     *            Preference is not persistent or this Preference is not present.
     * @return The value from the data store or the default return
     *         value.
     * @see #persistString(String)
     */
    protected String getPersistedString(String defaultReturnValue) {
        if (!shouldPersist()) {
            return defaultReturnValue;
        }

        PreferenceDataStore dataStore = getPreferenceDataStore();
        if (dataStore != null) {
            return dataStore.getString(mKey, defaultReturnValue);
        }

        return mPreferenceManager.getSharedPreferences().getString(mKey, defaultReturnValue);
    }

    
Attempts to persist a set of Strings if this Preference is persistent.

Params:
  • values – The values to persist.
See Also:
Returns:True if this Preference is persistent. (This is not whether the
        value was persisted, since we may not necessarily commit if there
        will be a batch commit later.)
/**
     * Attempts to persist a set of Strings if this Preference is persistent.
     *
     * @param values The values to persist.
     * @return True if this Preference is persistent. (This is not whether the
     *         value was persisted, since we may not necessarily commit if there
     *         will be a batch commit later.)
     * @see #getPersistedStringSet(Set)
     */
    public boolean persistStringSet(Set<String>  values) {
        if (!shouldPersist()) {
            return false;
        }

        // Shouldn't store null
        if (values.equals(getPersistedStringSet(null))) {
            // It's already there, so the same as persisting
            return true;
        }

        PreferenceDataStore dataStore = getPreferenceDataStore();
        if (dataStore != null) {
            dataStore.putStringSet(mKey, values);
        } else {
            SharedPreferences.Editor editor = mPreferenceManager.getEditor();
            editor.putStringSet(mKey, values);
            tryCommit(editor);
        }
        return true;
    }

    
Attempts to get a persisted set of Strings if this Preference is persistent.

Params:
  • defaultReturnValue – The default value to return if either this
           Preference is not persistent or this Preference is not present.
See Also:
Returns:The value from the data store or the default return
        value.
/**
     * Attempts to get a persisted set of Strings if this Preference is persistent.
     *
     * @param defaultReturnValue The default value to return if either this
     *            Preference is not persistent or this Preference is not present.
     * @return The value from the data store or the default return
     *         value.
     * @see #persistStringSet(Set)
     */
    public Set<String> getPersistedStringSet(Set<String> defaultReturnValue) {
        if (!shouldPersist()) {
            return defaultReturnValue;
        }

        PreferenceDataStore dataStore = getPreferenceDataStore();
        if (dataStore != null) {
            return dataStore.getStringSet(mKey, defaultReturnValue);
        }

        return mPreferenceManager.getSharedPreferences().getStringSet(mKey, defaultReturnValue);
    }

    
Attempts to persist an int if this Preference is persistent.

Params:
  • value – The value to persist.
See Also:
Returns:True if this Preference is persistent. (This is not whether the
        value was persisted, since we may not necessarily commit if there
        will be a batch commit later.)
/**
     * Attempts to persist an int if this Preference is persistent.
     *
     * @param value The value to persist.
     * @return True if this Preference is persistent. (This is not whether the
     *         value was persisted, since we may not necessarily commit if there
     *         will be a batch commit later.)
     * @see #persistString(String)
     * @see #getPersistedInt(int)
     */
    protected boolean persistInt(int value) {
        if (!shouldPersist()) {
            return false;
        }

        if (value == getPersistedInt(~value)) {
            // It's already there, so the same as persisting
            return true;
        }

        PreferenceDataStore dataStore = getPreferenceDataStore();
        if (dataStore != null) {
            dataStore.putInt(mKey, value);
        } else {
            SharedPreferences.Editor editor = mPreferenceManager.getEditor();
            editor.putInt(mKey, value);
            tryCommit(editor);
        }
        return true;
    }

    
Attempts to get a persisted int if this Preference is persistent.

Params:
  • defaultReturnValue – The default value to return if either this
           Preference is not persistent or this Preference is not present.
See Also:
Returns:The value from the data store or the default return
        value.
/**
     * Attempts to get a persisted int if this Preference is persistent.
     *
     * @param defaultReturnValue The default value to return if either this
     *            Preference is not persistent or this Preference is not present.
     * @return The value from the data store or the default return
     *         value.
     * @see #getPersistedString(String)
     * @see #persistInt(int)
     */
    protected int getPersistedInt(int defaultReturnValue) {
        if (!shouldPersist()) {
            return defaultReturnValue;
        }

        PreferenceDataStore dataStore = getPreferenceDataStore();
        if (dataStore != null) {
            return dataStore.getInt(mKey, defaultReturnValue);
        }

        return mPreferenceManager.getSharedPreferences().getInt(mKey, defaultReturnValue);
    }

    
Attempts to persist a long if this Preference is persistent.

Params:
  • value – The value to persist.
See Also:
Returns:True if this Preference is persistent. (This is not whether the
        value was persisted, since we may not necessarily commit if there
        will be a batch commit later.)
/**
     * Attempts to persist a long if this Preference is persistent.
     *
     * @param value The value to persist.
     * @return True if this Preference is persistent. (This is not whether the
     *         value was persisted, since we may not necessarily commit if there
     *         will be a batch commit later.)
     * @see #persistString(String)
     * @see #getPersistedFloat(float)
     */
    protected boolean persistFloat(float value) {
        if (!shouldPersist()) {
            return false;
        }

        if (value == getPersistedFloat(Float.NaN)) {
            // It's already there, so the same as persisting
            return true;
        }

        PreferenceDataStore dataStore = getPreferenceDataStore();
        if (dataStore != null) {
            dataStore.putFloat(mKey, value);
        } else {
            SharedPreferences.Editor editor = mPreferenceManager.getEditor();
            editor.putFloat(mKey, value);
            tryCommit(editor);
        }
        return true;
    }

    
Attempts to get a persisted float if this Preference is persistent.

Params:
  • defaultReturnValue – The default value to return if either this
           Preference is not persistent or this Preference is not present.
See Also:
Returns:The value from the data store or the default return
        value.
/**
     * Attempts to get a persisted float if this Preference is persistent.
     *
     * @param defaultReturnValue The default value to return if either this
     *            Preference is not persistent or this Preference is not present.
     * @return The value from the data store or the default return
     *         value.
     * @see #getPersistedString(String)
     * @see #persistFloat(float)
     */
    protected float getPersistedFloat(float defaultReturnValue) {
        if (!shouldPersist()) {
            return defaultReturnValue;
        }

        PreferenceDataStore dataStore = getPreferenceDataStore();
        if (dataStore != null) {
            return dataStore.getFloat(mKey, defaultReturnValue);
        }

        return mPreferenceManager.getSharedPreferences().getFloat(mKey, defaultReturnValue);
    }

    
Attempts to persist a long if this Preference is persistent.

Params:
  • value – The value to persist.
See Also:
Returns:True if this Preference is persistent. (This is not whether the
        value was persisted, since we may not necessarily commit if there
        will be a batch commit later.)
/**
     * Attempts to persist a long if this Preference is persistent.
     *
     * @param value The value to persist.
     * @return True if this Preference is persistent. (This is not whether the
     *         value was persisted, since we may not necessarily commit if there
     *         will be a batch commit later.)
     * @see #persistString(String)
     * @see #getPersistedLong(long)
     */
    protected boolean persistLong(long value) {
        if (!shouldPersist()) {
            return false;
        }

        if (value == getPersistedLong(~value)) {
            // It's already there, so the same as persisting
            return true;
        }

        PreferenceDataStore dataStore = getPreferenceDataStore();
        if (dataStore != null) {
            dataStore.putLong(mKey, value);
        } else {
            SharedPreferences.Editor editor = mPreferenceManager.getEditor();
            editor.putLong(mKey, value);
            tryCommit(editor);
        }
        return true;
    }

    
Attempts to get a persisted long if this Preference is persistent.

Params:
  • defaultReturnValue – The default value to return if either this
           Preference is not persistent or this Preference is not present.
See Also:
Returns:The value from the data store or the default return
        value.
/**
     * Attempts to get a persisted long if this Preference is persistent.
     *
     * @param defaultReturnValue The default value to return if either this
     *            Preference is not persistent or this Preference is not present.
     * @return The value from the data store or the default return
     *         value.
     * @see #getPersistedString(String)
     * @see #persistLong(long)
     */
    protected long getPersistedLong(long defaultReturnValue) {
        if (!shouldPersist()) {
            return defaultReturnValue;
        }

        PreferenceDataStore dataStore = getPreferenceDataStore();
        if (dataStore != null) {
            return dataStore.getLong(mKey, defaultReturnValue);
        }

        return mPreferenceManager.getSharedPreferences().getLong(mKey, defaultReturnValue);
    }

    
Attempts to persist a boolean if this Preference is persistent.

Params:
  • value – The value to persist.
See Also:
Returns:True if this Preference is persistent. (This is not whether the
        value was persisted, since we may not necessarily commit if there
        will be a batch commit later.)
/**
     * Attempts to persist a boolean if this Preference is persistent.
     *
     * @param value The value to persist.
     * @return True if this Preference is persistent. (This is not whether the
     *         value was persisted, since we may not necessarily commit if there
     *         will be a batch commit later.)
     * @see #persistString(String)
     * @see #getPersistedBoolean(boolean)
     */
    protected boolean persistBoolean(boolean value) {
        if (!shouldPersist()) {
            return false;
        }

        if (value == getPersistedBoolean(!value)) {
            // It's already there, so the same as persisting
            return true;
        }

        PreferenceDataStore dataStore = getPreferenceDataStore();
        if (dataStore != null) {
            dataStore.putBoolean(mKey, value);
        } else {
            SharedPreferences.Editor editor = mPreferenceManager.getEditor();
            editor.putBoolean(mKey, value);
            tryCommit(editor);
        }
        return true;
    }

    
Attempts to get a persisted boolean if this Preference is persistent.

Params:
  • defaultReturnValue – The default value to return if either this
           Preference is not persistent or this Preference is not present.
See Also:
Returns:The value from the data store or the default return
        value.
/**
     * Attempts to get a persisted boolean if this Preference is persistent.
     *
     * @param defaultReturnValue The default value to return if either this
     *            Preference is not persistent or this Preference is not present.
     * @return The value from the data store or the default return
     *         value.
     * @see #getPersistedString(String)
     * @see #persistBoolean(boolean)
     */
    protected boolean getPersistedBoolean(boolean defaultReturnValue) {
        if (!shouldPersist()) {
            return defaultReturnValue;
        }

        PreferenceDataStore dataStore = getPreferenceDataStore();
        if (dataStore != null) {
            return dataStore.getBoolean(mKey, defaultReturnValue);
        }

        return mPreferenceManager.getSharedPreferences().getBoolean(mKey, defaultReturnValue);
    }

    @Override
    public String toString() {
        return getFilterableStringBuilder().toString();
    }

    
Returns the text that will be used to filter this Preference depending on
user input.


If overridding and calling through to the superclass, make sure to prepend
your additions with a space.

Returns:Text as a StringBuilder that will be used to filter this preference. By default, this is the title and summary (concatenated with a space).
/**
     * Returns the text that will be used to filter this Preference depending on
     * user input.
     * <p>
     * If overridding and calling through to the superclass, make sure to prepend
     * your additions with a space.
     *
     * @return Text as a {@link StringBuilder} that will be used to filter this
     *         preference. By default, this is the title and summary
     *         (concatenated with a space).
     */
    StringBuilder getFilterableStringBuilder() {
        StringBuilder sb = new StringBuilder();
        CharSequence title = getTitle();
        if (!TextUtils.isEmpty(title)) {
            sb.append(title).append(' ');
        }
        CharSequence summary = getSummary();
        if (!TextUtils.isEmpty(summary)) {
            sb.append(summary).append(' ');
        }
        if (sb.length() > 0) {
            // Drop the last space
            sb.setLength(sb.length() - 1);
        }
        return sb;
    }

    
Store this Preference hierarchy's frozen state into the given container.

Params:
  • container – The Bundle in which to save the instance of this Preference.
See Also:
/**
     * Store this Preference hierarchy's frozen state into the given container.
     *
     * @param container The Bundle in which to save the instance of this Preference.
     *
     * @see #restoreHierarchyState
     * @see #onSaveInstanceState
     */
    public void saveHierarchyState(Bundle container) {
        dispatchSaveInstanceState(container);
    }

    
Called by saveHierarchyState to store the instance for this Preference and its children. May be overridden to modify how the save happens for children. For example, some Preference objects may want to not store an instance for their children. 
Params:
  • container – The Bundle in which to save the instance of this Preference.
See Also:
/**
     * Called by {@link #saveHierarchyState} to store the instance for this Preference and its
     * children. May be overridden to modify how the save happens for children. For example, some
     * Preference objects may want to not store an instance for their children.
     *
     * @param container The Bundle in which to save the instance of this Preference.
     *
     * @see #saveHierarchyState
     * @see #onSaveInstanceState
     */
    void dispatchSaveInstanceState(Bundle container) {
        if (hasKey()) {
            mBaseMethodCalled = false;
            Parcelable state = onSaveInstanceState();
            if (!mBaseMethodCalled) {
                throw new IllegalStateException(
                        "Derived class did not call super.onSaveInstanceState()");
            }
            if (state != null) {
                container.putParcelable(mKey, state);
            }
        }
    }

    
Hook allowing a Preference to generate a representation of its internal
state that can later be used to create a new instance with that same
state. This state should only contain information that is not persistent
or can be reconstructed later.

See Also:
Returns:A Parcelable object containing the current dynamic state of this Preference, or null if there is nothing interesting to save. The default implementation returns null.
/**
     * Hook allowing a Preference to generate a representation of its internal
     * state that can later be used to create a new instance with that same
     * state. This state should only contain information that is not persistent
     * or can be reconstructed later.
     *
     * @return A Parcelable object containing the current dynamic state of this Preference, or
     *         {@code null} if there is nothing interesting to save. The default implementation
     *         returns {@code null}.
     * @see #onRestoreInstanceState
     * @see #saveHierarchyState
     */
    protected Parcelable onSaveInstanceState() {
        mBaseMethodCalled = true;
        return BaseSavedState.EMPTY_STATE;
    }

    
Restore this Preference hierarchy's previously saved state from the given container.

Params:
  • container – The Bundle that holds the previously saved state.
See Also:
/**
     * Restore this Preference hierarchy's previously saved state from the given container.
     *
     * @param container The Bundle that holds the previously saved state.
     *
     * @see #saveHierarchyState
     * @see #onRestoreInstanceState
     */
    public void restoreHierarchyState(Bundle container) {
        dispatchRestoreInstanceState(container);
    }

    
Called by restoreHierarchyState to retrieve the saved state for this Preference and its children. May be overridden to modify how restoring happens to the children of a Preference. For example, some Preference objects may not want to save state for their children. 
Params:
  • container – The Bundle that holds the previously saved state.
See Also:
/**
     * Called by {@link #restoreHierarchyState} to retrieve the saved state for this
     * Preference and its children. May be overridden to modify how restoring
     * happens to the children of a Preference. For example, some Preference objects may
     * not want to save state for their children.
     *
     * @param container The Bundle that holds the previously saved state.
     * @see #restoreHierarchyState
     * @see #onRestoreInstanceState
     */
    void dispatchRestoreInstanceState(Bundle container) {
        if (hasKey()) {
            Parcelable state = container.getParcelable(mKey);
            if (state != null) {
                mBaseMethodCalled = false;
                onRestoreInstanceState(state);
                if (!mBaseMethodCalled) {
                    throw new IllegalStateException(
                            "Derived class did not call super.onRestoreInstanceState()");
                }
            }
        }
    }

    
Hook allowing a Preference to re-apply a representation of its internal state that had previously been generated by onSaveInstanceState. This function will never be called with a null state. 
Params:
See Also:
/**
     * Hook allowing a Preference to re-apply a representation of its internal state that had
     * previously been generated by {@link #onSaveInstanceState}. This function will never be called
     * with a {@code null} state.
     *
     * @param state The saved state that had previously been returned by
     *            {@link #onSaveInstanceState}.
     * @see #onSaveInstanceState
     * @see #restoreHierarchyState
     */
    protected void onRestoreInstanceState(Parcelable state) {
        mBaseMethodCalled = true;
        if (state != BaseSavedState.EMPTY_STATE && state != null) {
            throw new IllegalArgumentException("Wrong state class -- expecting Preference State");
        }
    }

    
A base class for managing the instance state of a Preference. 
/**
     * A base class for managing the instance state of a {@link Preference}.
     */
    public static class BaseSavedState extends AbsSavedState {
        public BaseSavedState(Parcel source) {
            super(source);
        }

        public BaseSavedState(Parcelable superState) {
            super(superState);
        }

        public static final Parcelable.Creator<BaseSavedState> CREATOR =
                new Parcelable.Creator<BaseSavedState>() {
                    public BaseSavedState createFromParcel(Parcel in) {
                        return new BaseSavedState(in);
                    }

                    public BaseSavedState[] newArray(int size) {
                        return new BaseSavedState[size];
                    }
                };
    }

}