https://source.android.com/ 
/*
 * Copyright (C) 2006 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.graphics.drawable;

import android.annotation.NonNull;
import android.annotation.Nullable;
import android.content.pm.ActivityInfo.Config;
import android.content.res.ColorStateList;
import android.content.res.Resources;
import android.content.res.Resources.Theme;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.ColorFilter;
import android.graphics.Outline;
import android.graphics.PixelFormat;
import android.graphics.PorterDuff.Mode;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.LayoutDirection;
import android.util.Log;
import android.view.Gravity;
import android.view.View;

import com.android.internal.R;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import java.io.IOException;


A Drawable that manages an array of other Drawables. These are drawn in array
order, so the element with the largest index will be drawn on top.


It can be defined in an XML file with the <layer-list> element.
Each Drawable in the layer is defined in a nested <item>.


For more information, see the guide to
Drawable Resources.

@attrref android.R.styleable#LayerDrawable_paddingMode
@attrref android.R.styleable#LayerDrawableItem_left
@attrref android.R.styleable#LayerDrawableItem_top
@attrref android.R.styleable#LayerDrawableItem_right
@attrref android.R.styleable#LayerDrawableItem_bottom
@attrref android.R.styleable#LayerDrawableItem_start
@attrref android.R.styleable#LayerDrawableItem_end
@attrref android.R.styleable#LayerDrawableItem_width
@attrref android.R.styleable#LayerDrawableItem_height
@attrref android.R.styleable#LayerDrawableItem_gravity
@attrref android.R.styleable#LayerDrawableItem_drawable
@attrref android.R.styleable#LayerDrawableItem_id
/**
 * A Drawable that manages an array of other Drawables. These are drawn in array
 * order, so the element with the largest index will be drawn on top.
 * <p>
 * It can be defined in an XML file with the <code>&lt;layer-list></code> element.
 * Each Drawable in the layer is defined in a nested <code>&lt;item></code>.
 * <p>
 * For more information, see the guide to
 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>.
 *
 * @attr ref android.R.styleable#LayerDrawable_paddingMode
 * @attr ref android.R.styleable#LayerDrawableItem_left
 * @attr ref android.R.styleable#LayerDrawableItem_top
 * @attr ref android.R.styleable#LayerDrawableItem_right
 * @attr ref android.R.styleable#LayerDrawableItem_bottom
 * @attr ref android.R.styleable#LayerDrawableItem_start
 * @attr ref android.R.styleable#LayerDrawableItem_end
 * @attr ref android.R.styleable#LayerDrawableItem_width
 * @attr ref android.R.styleable#LayerDrawableItem_height
 * @attr ref android.R.styleable#LayerDrawableItem_gravity
 * @attr ref android.R.styleable#LayerDrawableItem_drawable
 * @attr ref android.R.styleable#LayerDrawableItem_id
*/
public class LayerDrawable extends Drawable implements Drawable.Callback {
    private static final String LOG_TAG = "LayerDrawable";

    
Padding mode used to nest each layer inside the padding of the previous
layer.

See Also:
  • setPaddingMode(int)
/**
     * Padding mode used to nest each layer inside the padding of the previous
     * layer.
     *
     * @see #setPaddingMode(int)
     */
    public static final int PADDING_MODE_NEST = 0;

    
Padding mode used to stack each layer directly atop the previous layer.

See Also:
  • setPaddingMode(int)
/**
     * Padding mode used to stack each layer directly atop the previous layer.
     *
     * @see #setPaddingMode(int)
     */
    public static final int PADDING_MODE_STACK = 1;

    
Value used for undefined start and end insets.

See Also:
/**
     * Value used for undefined start and end insets.
     *
     * @see #getLayerInsetStart(int)
     * @see #getLayerInsetEnd(int)
     */
    public static final int INSET_UNDEFINED = Integer.MIN_VALUE;

    @NonNull
    LayerState mLayerState;

    private int[] mPaddingL;
    private int[] mPaddingT;
    private int[] mPaddingR;
    private int[] mPaddingB;

    private final Rect mTmpRect = new Rect();
    private final Rect mTmpOutRect = new Rect();
    private final Rect mTmpContainer = new Rect();
    private Rect mHotspotBounds;
    private boolean mMutated;

    private boolean mSuspendChildInvalidation;
    private boolean mChildRequestedInvalidation;

    
Creates a new layer drawable with the list of specified layers.

Params:
  • layers – a list of drawables to use as layers in this new drawable,
              must be non-null
/**
     * Creates a new layer drawable with the list of specified layers.
     *
     * @param layers a list of drawables to use as layers in this new drawable,
     *               must be non-null
     */
    public LayerDrawable(@NonNull Drawable[] layers) {
        this(layers, null);
    }

    
Creates a new layer drawable with the specified list of layers and the
specified constant state.

Params:
  • layers – The list of layers to add to this drawable.
  • state – The constant drawable state.
/**
     * Creates a new layer drawable with the specified list of layers and the
     * specified constant state.
     *
     * @param layers The list of layers to add to this drawable.
     * @param state The constant drawable state.
     */
    LayerDrawable(@NonNull Drawable[] layers, @Nullable LayerState state) {
        this(state, null);

        if (layers == null) {
            throw new IllegalArgumentException("layers must be non-null");
        }

        final int length = layers.length;
        final ChildDrawable[] r = new ChildDrawable[length];
        for (int i = 0; i < length; i++) {
            r[i] = new ChildDrawable(mLayerState.mDensity);
            r[i].mDrawable = layers[i];
            layers[i].setCallback(this);
            mLayerState.mChildrenChangingConfigurations |= layers[i].getChangingConfigurations();
        }
        mLayerState.mNumChildren = length;
        mLayerState.mChildren = r;

        ensurePadding();
        refreshPadding();
    }

    LayerDrawable() {
        this((LayerState) null, null);
    }

    
The one constructor to rule them all. This is called by all public
constructors to set the state and initialize local properties.

/**
     * The one constructor to rule them all. This is called by all public
     * constructors to set the state and initialize local properties.
     */
    LayerDrawable(@Nullable LayerState state, @Nullable Resources res) {
        mLayerState = createConstantState(state, res);
        if (mLayerState.mNumChildren > 0) {
            ensurePadding();
            refreshPadding();
        }
    }

    LayerState createConstantState(@Nullable LayerState state, @Nullable Resources res) {
        return new LayerState(state, this, res);
    }

    @Override
    public void inflate(@NonNull Resources r, @NonNull XmlPullParser parser,
            @NonNull AttributeSet attrs, @Nullable Theme theme)
            throws XmlPullParserException, IOException {
        super.inflate(r, parser, attrs, theme);

        // The density may have changed since the last update. This will
        // apply scaling to any existing constant state properties.
        final LayerState state = mLayerState;
        final int density = Drawable.resolveDensity(r, 0);
        state.setDensity(density);

        final TypedArray a = obtainAttributes(r, theme, attrs, R.styleable.LayerDrawable);
        updateStateFromTypedArray(a);
        a.recycle();

        final ChildDrawable[] array = state.mChildren;
        final int N = state.mNumChildren;
        for (int i = 0; i < N; i++) {
            final ChildDrawable layer = array[i];
            layer.setDensity(density);
        }

        inflateLayers(r, parser, attrs, theme);

        ensurePadding();
        refreshPadding();
    }

    @Override
    public void applyTheme(@NonNull Theme t) {
        super.applyTheme(t);

        final LayerState state = mLayerState;
        final int density = Drawable.resolveDensity(t.getResources(), 0);
        state.setDensity(density);

        if (state.mThemeAttrs != null) {
            final TypedArray a = t.resolveAttributes(
                    state.mThemeAttrs, R.styleable.LayerDrawable);
            updateStateFromTypedArray(a);
            a.recycle();
        }

        final ChildDrawable[] array = state.mChildren;
        final int N = state.mNumChildren;
        for (int i = 0; i < N; i++) {
            final ChildDrawable layer = array[i];
            layer.setDensity(density);

            if (layer.mThemeAttrs != null) {
                final TypedArray a = t.resolveAttributes(
                        layer.mThemeAttrs, R.styleable.LayerDrawableItem);
                updateLayerFromTypedArray(layer, a);
                a.recycle();
            }

            final Drawable d = layer.mDrawable;
            if (d != null && d.canApplyTheme()) {
                d.applyTheme(t);

                // Update cached mask of child changing configurations.
                state.mChildrenChangingConfigurations |= d.getChangingConfigurations();
            }
        }
    }

    
Inflates child layers using the specified parser.

/**
     * Inflates child layers using the specified parser.
     */
    private void inflateLayers(@NonNull Resources r, @NonNull XmlPullParser parser,
            @NonNull AttributeSet attrs, @Nullable Theme theme)
            throws XmlPullParserException, IOException {
        final LayerState state = mLayerState;

        final int innerDepth = parser.getDepth() + 1;
        int type;
        int depth;
        while ((type = parser.next()) != XmlPullParser.END_DOCUMENT
                && ((depth = parser.getDepth()) >= innerDepth || type != XmlPullParser.END_TAG)) {
            if (type != XmlPullParser.START_TAG) {
                continue;
            }

            if (depth > innerDepth || !parser.getName().equals("item")) {
                continue;
            }

            final ChildDrawable layer = new ChildDrawable(state.mDensity);
            final TypedArray a = obtainAttributes(r, theme, attrs, R.styleable.LayerDrawableItem);
            updateLayerFromTypedArray(layer, a);
            a.recycle();

            // If the layer doesn't have a drawable or unresolved theme
            // attribute for a drawable, attempt to parse one from the child
            // element. If multiple child elements exist, we'll only use the
            // first one.
            if (layer.mDrawable == null && (layer.mThemeAttrs == null ||
                    layer.mThemeAttrs[R.styleable.LayerDrawableItem_drawable] == 0)) {
                while ((type = parser.next()) == XmlPullParser.TEXT) {
                }
                if (type != XmlPullParser.START_TAG) {
                    throw new XmlPullParserException(parser.getPositionDescription()
                            + ": <item> tag requires a 'drawable' attribute or "
                            + "child tag defining a drawable");
                }

                // We found a child drawable. Take ownership.
                layer.mDrawable = Drawable.createFromXmlInner(r, parser, attrs, theme);
                layer.mDrawable.setCallback(this);
                state.mChildrenChangingConfigurations |=
                        layer.mDrawable.getChangingConfigurations();
            }

            addLayer(layer);
        }
    }

    
Initializes the constant state from the values in the typed array.

/**
     * Initializes the constant state from the values in the typed array.
     */
    private void updateStateFromTypedArray(@NonNull TypedArray a) {
        final LayerState state = mLayerState;

        // Account for any configuration changes.
        state.mChangingConfigurations |= a.getChangingConfigurations();

        // Extract the theme attributes, if any.
        state.mThemeAttrs = a.extractThemeAttrs();

        final int N = a.getIndexCount();
        for (int i = 0; i < N; i++) {
            final int attr = a.getIndex(i);
            switch (attr) {
                case R.styleable.LayerDrawable_opacity:
                    state.mOpacityOverride = a.getInt(attr, state.mOpacityOverride);
                    break;
                case R.styleable.LayerDrawable_paddingTop:
                    state.mPaddingTop = a.getDimensionPixelOffset(attr, state.mPaddingTop);
                    break;
                case R.styleable.LayerDrawable_paddingBottom:
                    state.mPaddingBottom = a.getDimensionPixelOffset(attr, state.mPaddingBottom);
                    break;
                case R.styleable.LayerDrawable_paddingLeft:
                    state.mPaddingLeft = a.getDimensionPixelOffset(attr, state.mPaddingLeft);
                    break;
                case R.styleable.LayerDrawable_paddingRight:
                    state.mPaddingRight = a.getDimensionPixelOffset(attr, state.mPaddingRight);
                    break;
                case R.styleable.LayerDrawable_paddingStart:
                    state.mPaddingStart = a.getDimensionPixelOffset(attr, state.mPaddingStart);
                    break;
                case R.styleable.LayerDrawable_paddingEnd:
                    state.mPaddingEnd = a.getDimensionPixelOffset(attr, state.mPaddingEnd);
                    break;
                case R.styleable.LayerDrawable_autoMirrored:
                    state.mAutoMirrored = a.getBoolean(attr, state.mAutoMirrored);
                    break;
                case R.styleable.LayerDrawable_paddingMode:
                    state.mPaddingMode = a.getInteger(attr, state.mPaddingMode);
                    break;
            }
        }
    }

    private void updateLayerFromTypedArray(@NonNull ChildDrawable layer, @NonNull TypedArray a) {
        final LayerState state = mLayerState;

        // Account for any configuration changes.
        state.mChildrenChangingConfigurations |= a.getChangingConfigurations();

        // Extract the theme attributes, if any.
        layer.mThemeAttrs = a.extractThemeAttrs();

        final int N = a.getIndexCount();
        for (int i = 0; i < N; i++) {
            final int attr = a.getIndex(i);
            switch (attr) {
                case R.styleable.LayerDrawableItem_left:
                    layer.mInsetL = a.getDimensionPixelOffset(attr, layer.mInsetL);
                    break;
                case R.styleable.LayerDrawableItem_top:
                    layer.mInsetT = a.getDimensionPixelOffset(attr, layer.mInsetT);
                    break;
                case R.styleable.LayerDrawableItem_right:
                    layer.mInsetR = a.getDimensionPixelOffset(attr, layer.mInsetR);
                    break;
                case R.styleable.LayerDrawableItem_bottom:
                    layer.mInsetB = a.getDimensionPixelOffset(attr, layer.mInsetB);
                    break;
                case R.styleable.LayerDrawableItem_start:
                    layer.mInsetS = a.getDimensionPixelOffset(attr, layer.mInsetS);
                    break;
                case R.styleable.LayerDrawableItem_end:
                    layer.mInsetE = a.getDimensionPixelOffset(attr, layer.mInsetE);
                    break;
                case R.styleable.LayerDrawableItem_width:
                    layer.mWidth = a.getDimensionPixelSize(attr, layer.mWidth);
                    break;
                case R.styleable.LayerDrawableItem_height:
                    layer.mHeight = a.getDimensionPixelSize(attr, layer.mHeight);
                    break;
                case R.styleable.LayerDrawableItem_gravity:
                    layer.mGravity = a.getInteger(attr, layer.mGravity);
                    break;
                case R.styleable.LayerDrawableItem_id:
                    layer.mId = a.getResourceId(attr, layer.mId);
                    break;
            }
        }

        final Drawable dr = a.getDrawable(R.styleable.LayerDrawableItem_drawable);
        if (dr != null) {
            if (layer.mDrawable != null) {
                // It's possible that a drawable was already set, in which case
                // we should clear the callback. We may have also integrated the
                // drawable's changing configurations, but we don't have enough
                // information to revert that change.
                layer.mDrawable.setCallback(null);
            }

            // Take ownership of the new drawable.
            layer.mDrawable = dr;
            layer.mDrawable.setCallback(this);
            state.mChildrenChangingConfigurations |=
                    layer.mDrawable.getChangingConfigurations();
        }
    }

    @Override
    public boolean canApplyTheme() {
        return mLayerState.canApplyTheme() || super.canApplyTheme();
    }

    
@hide
/**
     * @hide
     */
    @Override
    public boolean isProjected() {
        if (super.isProjected()) {
            return true;
        }

        final ChildDrawable[] layers = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            if (layers[i].mDrawable.isProjected()) {
                return true;
            }
        }

        return false;
    }

    
Adds a new layer at the end of list of layers and returns its index.

Params:
  • layer – The layer to add.
Returns:The index of the layer.
/**
     * Adds a new layer at the end of list of layers and returns its index.
     *
     * @param layer The layer to add.
     * @return The index of the layer.
     */
    int addLayer(@NonNull ChildDrawable layer) {
        final LayerState st = mLayerState;
        final int N = st.mChildren != null ? st.mChildren.length : 0;
        final int i = st.mNumChildren;
        if (i >= N) {
            final ChildDrawable[] nu = new ChildDrawable[N + 10];
            if (i > 0) {
                System.arraycopy(st.mChildren, 0, nu, 0, i);
            }

            st.mChildren = nu;
        }

        st.mChildren[i] = layer;
        st.mNumChildren++;
        st.invalidateCache();
        return i;
    }

    
Add a new layer to this drawable. The new layer is identified by an id.

Params:
  • dr – The drawable to add as a layer.
  • themeAttrs – Theme attributes extracted from the layer.
  • id – The id of the new layer.
  • left – The left padding of the new layer.
  • top – The top padding of the new layer.
  • right – The right padding of the new layer.
  • bottom – The bottom padding of the new layer.
/**
     * Add a new layer to this drawable. The new layer is identified by an id.
     *
     * @param dr The drawable to add as a layer.
     * @param themeAttrs Theme attributes extracted from the layer.
     * @param id The id of the new layer.
     * @param left The left padding of the new layer.
     * @param top The top padding of the new layer.
     * @param right The right padding of the new layer.
     * @param bottom The bottom padding of the new layer.
     */
    ChildDrawable addLayer(Drawable dr, int[] themeAttrs, int id,
            int left, int top, int right, int bottom) {
        final ChildDrawable childDrawable = createLayer(dr);
        childDrawable.mId = id;
        childDrawable.mThemeAttrs = themeAttrs;
        childDrawable.mDrawable.setAutoMirrored(isAutoMirrored());
        childDrawable.mInsetL = left;
        childDrawable.mInsetT = top;
        childDrawable.mInsetR = right;
        childDrawable.mInsetB = bottom;

        addLayer(childDrawable);

        mLayerState.mChildrenChangingConfigurations |= dr.getChangingConfigurations();
        dr.setCallback(this);

        return childDrawable;
    }

    private ChildDrawable createLayer(Drawable dr) {
        final ChildDrawable layer = new ChildDrawable(mLayerState.mDensity);
        layer.mDrawable = dr;
        return layer;
    }

    
Adds a new layer containing the specified drawable to the end of the layer list and returns its index. 
Params:
  • dr – The drawable to add as a new layer.
Returns:The index of the new layer.
/**
     * Adds a new layer containing the specified {@code drawable} to the end of
     * the layer list and returns its index.
     *
     * @param dr The drawable to add as a new layer.
     * @return The index of the new layer.
     */
    public int addLayer(Drawable dr) {
        final ChildDrawable layer = createLayer(dr);
        final int index = addLayer(layer);
        ensurePadding();
        refreshChildPadding(index, layer);
        return index;
    }

    
Looks for a layer with the given ID and returns its Drawable. 
 If multiple layers are found for the given ID, returns the Drawable for the matching layer at the highest index. 
Params:
  • id – The layer ID to search for.
Returns:The Drawable for the highest-indexed layer that has the given ID, or null if not found.
/**
     * Looks for a layer with the given ID and returns its {@link Drawable}.
     * <p>
     * If multiple layers are found for the given ID, returns the
     * {@link Drawable} for the matching layer at the highest index.
     *
     * @param id The layer ID to search for.
     * @return The {@link Drawable} for the highest-indexed layer that has the
     *         given ID, or null if not found.
     */
    public Drawable findDrawableByLayerId(int id) {
        final ChildDrawable[] layers = mLayerState.mChildren;
        for (int i = mLayerState.mNumChildren - 1; i >= 0; i--) {
            if (layers[i].mId == id) {
                return layers[i].mDrawable;
            }
        }

        return null;
    }

    
Sets the ID of a layer.

Params:
  • index – The index of the layer to modify, must be in the range 0...getNumberOfLayers()-1.
  • id – The id to assign to the layer.
See Also:
@attrref android.R.styleable#LayerDrawableItem_id
/**
     * Sets the ID of a layer.
     *
     * @param index The index of the layer to modify, must be in the range
     *              {@code 0...getNumberOfLayers()-1}.
     * @param id The id to assign to the layer.
     *
     * @see #getId(int)
     * @attr ref android.R.styleable#LayerDrawableItem_id
     */
    public void setId(int index, int id) {
        mLayerState.mChildren[index].mId = id;
    }

    
Returns the ID of the specified layer.

Params:
  • index – The index of the layer, must be in the range 0...getNumberOfLayers()-1.
See Also:
Returns:The id of the layer or View.NO_ID if the layer has no id.
@attrref android.R.styleable#LayerDrawableItem_id
/**
     * Returns the ID of the specified layer.
     *
     * @param index The index of the layer, must be in the range
     *              {@code 0...getNumberOfLayers()-1}.
     * @return The id of the layer or {@link android.view.View#NO_ID} if the
     *         layer has no id.
     *
     * @see #setId(int, int)
     * @attr ref android.R.styleable#LayerDrawableItem_id
     */
    public int getId(int index) {
        if (index >= mLayerState.mNumChildren) {
            throw new IndexOutOfBoundsException();
        }
        return mLayerState.mChildren[index].mId;
    }

    
Returns the number of layers contained within this layer drawable.

Returns:The number of layers.
/**
     * Returns the number of layers contained within this layer drawable.
     *
     * @return The number of layers.
     */
    public int getNumberOfLayers() {
        return mLayerState.mNumChildren;
    }

    
Replaces the Drawable for the layer with the given id. 
Params:
  • id – The layer ID to search for.
  • drawable – The replacement Drawable.
Returns:Whether the Drawable was replaced (could return false if the id was not found).
/**
     * Replaces the {@link Drawable} for the layer with the given id.
     *
     * @param id The layer ID to search for.
     * @param drawable The replacement {@link Drawable}.
     * @return Whether the {@link Drawable} was replaced (could return false if
     *         the id was not found).
     */
    public boolean setDrawableByLayerId(int id, Drawable drawable) {
        final int index = findIndexByLayerId(id);
        if (index < 0) {
            return false;
        }

        setDrawable(index, drawable);
        return true;
    }

    
Returns the layer with the specified id. 

If multiple layers have the same ID, returns the layer with the lowest
index.

Params:
  • id – The ID of the layer to return.
Returns:The index of the layer with the specified ID.
/**
     * Returns the layer with the specified {@code id}.
     * <p>
     * If multiple layers have the same ID, returns the layer with the lowest
     * index.
     *
     * @param id The ID of the layer to return.
     * @return The index of the layer with the specified ID.
     */
    public int findIndexByLayerId(int id) {
        final ChildDrawable[] layers = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final ChildDrawable childDrawable = layers[i];
            if (childDrawable.mId == id) {
                return i;
            }
        }

        return -1;
    }

    
Sets the drawable for the layer at the specified index.

Params:
  • index – The index of the layer to modify, must be in the range 0...getNumberOfLayers()-1.
  • drawable – The drawable to set for the layer.
See Also:
@attrref android.R.styleable#LayerDrawableItem_drawable
/**
     * Sets the drawable for the layer at the specified index.
     *
     * @param index The index of the layer to modify, must be in the range
     *              {@code 0...getNumberOfLayers()-1}.
     * @param drawable The drawable to set for the layer.
     *
     * @see #getDrawable(int)
     * @attr ref android.R.styleable#LayerDrawableItem_drawable
     */
    public void setDrawable(int index, Drawable drawable) {
        if (index >= mLayerState.mNumChildren) {
            throw new IndexOutOfBoundsException();
        }

        final ChildDrawable[] layers = mLayerState.mChildren;
        final ChildDrawable childDrawable = layers[index];
        if (childDrawable.mDrawable != null) {
            if (drawable != null) {
                final Rect bounds = childDrawable.mDrawable.getBounds();
                drawable.setBounds(bounds);
            }

            childDrawable.mDrawable.setCallback(null);
        }

        if (drawable != null) {
            drawable.setCallback(this);
        }

        childDrawable.mDrawable = drawable;
        mLayerState.invalidateCache();

        refreshChildPadding(index, childDrawable);
    }

    
Returns the drawable for the layer at the specified index.

Params:
  • index – The index of the layer, must be in the range 0...getNumberOfLayers()-1.
See Also:
Returns:The Drawable at the specified layer index.
@attrref android.R.styleable#LayerDrawableItem_drawable
/**
     * Returns the drawable for the layer at the specified index.
     *
     * @param index The index of the layer, must be in the range
     *              {@code 0...getNumberOfLayers()-1}.
     * @return The {@link Drawable} at the specified layer index.
     *
     * @see #setDrawable(int, Drawable)
     * @attr ref android.R.styleable#LayerDrawableItem_drawable
     */
    public Drawable getDrawable(int index) {
        if (index >= mLayerState.mNumChildren) {
            throw new IndexOutOfBoundsException();
        }
        return mLayerState.mChildren[index].mDrawable;
    }

    
Sets an explicit size for the specified layer.


Note: Setting an explicit layer size changes the default layer gravity behavior. See setLayerGravity(int, int) for more information. 
Params:
  • index – the index of the layer to adjust
  • w – width in pixels, or -1 to use the intrinsic width
  • h – height in pixels, or -1 to use the intrinsic height
See Also:
@attrref android.R.styleable#LayerDrawableItem_width
@attrref android.R.styleable#LayerDrawableItem_height
/**
     * Sets an explicit size for the specified layer.
     * <p>
     * <strong>Note:</strong> Setting an explicit layer size changes the
     * default layer gravity behavior. See {@link #setLayerGravity(int, int)}
     * for more information.
     *
     * @param index the index of the layer to adjust
     * @param w width in pixels, or -1 to use the intrinsic width
     * @param h height in pixels, or -1 to use the intrinsic height
     * @see #getLayerWidth(int)
     * @see #getLayerHeight(int)
     * @attr ref android.R.styleable#LayerDrawableItem_width
     * @attr ref android.R.styleable#LayerDrawableItem_height
     */
    public void setLayerSize(int index, int w, int h) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        childDrawable.mWidth = w;
        childDrawable.mHeight = h;
    }

    
Params:
  • index – the index of the layer to adjust
  • w – width in pixels, or -1 to use the intrinsic width
@attrref android.R.styleable#LayerDrawableItem_width
/**
     * @param index the index of the layer to adjust
     * @param w width in pixels, or -1 to use the intrinsic width
     * @attr ref android.R.styleable#LayerDrawableItem_width
     */
    public void setLayerWidth(int index, int w) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        childDrawable.mWidth = w;
    }

    
Params:
  • index – the index of the drawable to adjust
See Also:
Returns:the explicit width of the layer, or -1 if not specified
@attrref android.R.styleable#LayerDrawableItem_width
/**
     * @param index the index of the drawable to adjust
     * @return the explicit width of the layer, or -1 if not specified
     * @see #setLayerSize(int, int, int)
     * @attr ref android.R.styleable#LayerDrawableItem_width
     */
    public int getLayerWidth(int index) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        return childDrawable.mWidth;
    }

    
Params:
  • index – the index of the layer to adjust
  • h – height in pixels, or -1 to use the intrinsic height
@attrref android.R.styleable#LayerDrawableItem_height
/**
     * @param index the index of the layer to adjust
     * @param h height in pixels, or -1 to use the intrinsic height
     * @attr ref android.R.styleable#LayerDrawableItem_height
     */
    public void setLayerHeight(int index, int h) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        childDrawable.mHeight = h;
    }

    
Params:
  • index – the index of the drawable to adjust
See Also:
Returns:the explicit height of the layer, or -1 if not specified
@attrref android.R.styleable#LayerDrawableItem_height
/**
     * @param index the index of the drawable to adjust
     * @return the explicit height of the layer, or -1 if not specified
     * @see #setLayerSize(int, int, int)
     * @attr ref android.R.styleable#LayerDrawableItem_height
     */
    public int getLayerHeight(int index) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        return childDrawable.mHeight;
    }

    
Sets the gravity used to position or stretch the specified layer within its container. Gravity is applied after any layer insets (see setLayerInset(int, int, int, int, int)) or padding (see setPaddingMode(int)). 
 If gravity is specified as Gravity.NO_GRAVITY, the default behavior depends on whether an explicit width or height has been set (see setLayerSize(int, int, int)), If a dimension is not set, gravity in that direction defaults to Gravity.FILL_HORIZONTAL or Gravity.FILL_VERTICAL; otherwise, gravity in that direction defaults to Gravity.LEFT or Gravity.TOP. 
Params:
  • index – the index of the drawable to adjust
  • gravity – the gravity to set for the layer
See Also:
@attrref android.R.styleable#LayerDrawableItem_gravity
/**
     * Sets the gravity used to position or stretch the specified layer within
     * its container. Gravity is applied after any layer insets (see
     * {@link #setLayerInset(int, int, int, int, int)}) or padding (see
     * {@link #setPaddingMode(int)}).
     * <p>
     * If gravity is specified as {@link Gravity#NO_GRAVITY}, the default
     * behavior depends on whether an explicit width or height has been set
     * (see {@link #setLayerSize(int, int, int)}), If a dimension is not set,
     * gravity in that direction defaults to {@link Gravity#FILL_HORIZONTAL} or
     * {@link Gravity#FILL_VERTICAL}; otherwise, gravity in that direction
     * defaults to {@link Gravity#LEFT} or {@link Gravity#TOP}.
     *
     * @param index the index of the drawable to adjust
     * @param gravity the gravity to set for the layer
     *
     * @see #getLayerGravity(int)
     * @attr ref android.R.styleable#LayerDrawableItem_gravity
     */
    public void setLayerGravity(int index, int gravity) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        childDrawable.mGravity = gravity;
    }

    
Params:
  • index – the index of the layer
See Also:
Returns:the gravity used to position or stretch the specified layer
        within its container
@attrref android.R.styleable#LayerDrawableItem_gravity
/**
     * @param index the index of the layer
     * @return the gravity used to position or stretch the specified layer
     *         within its container
     *
     * @see #setLayerGravity(int, int)
     * @attr ref android.R.styleable#LayerDrawableItem_gravity
     */
    public int getLayerGravity(int index) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        return childDrawable.mGravity;
    }

    
Specifies the insets in pixels for the drawable at the specified index.

Params:
  • index – the index of the drawable to adjust
  • l – number of pixels to add to the left bound
  • t – number of pixels to add to the top bound
  • r – number of pixels to subtract from the right bound
  • b – number of pixels to subtract from the bottom bound
@attrref android.R.styleable#LayerDrawableItem_left
@attrref android.R.styleable#LayerDrawableItem_top
@attrref android.R.styleable#LayerDrawableItem_right
@attrref android.R.styleable#LayerDrawableItem_bottom
/**
     * Specifies the insets in pixels for the drawable at the specified index.
     *
     * @param index the index of the drawable to adjust
     * @param l number of pixels to add to the left bound
     * @param t number of pixels to add to the top bound
     * @param r number of pixels to subtract from the right bound
     * @param b number of pixels to subtract from the bottom bound
     *
     * @attr ref android.R.styleable#LayerDrawableItem_left
     * @attr ref android.R.styleable#LayerDrawableItem_top
     * @attr ref android.R.styleable#LayerDrawableItem_right
     * @attr ref android.R.styleable#LayerDrawableItem_bottom
     */
    public void setLayerInset(int index, int l, int t, int r, int b) {
        setLayerInsetInternal(index, l, t, r, b, INSET_UNDEFINED, INSET_UNDEFINED);
    }

    
Specifies the relative insets in pixels for the drawable at the
specified index.

Params:
  • index – the index of the layer to adjust
  • s – number of pixels to inset from the start bound
  • t – number of pixels to inset from the top bound
  • e – number of pixels to inset from the end bound
  • b – number of pixels to inset from the bottom bound
@attrref android.R.styleable#LayerDrawableItem_start
@attrref android.R.styleable#LayerDrawableItem_top
@attrref android.R.styleable#LayerDrawableItem_end
@attrref android.R.styleable#LayerDrawableItem_bottom
/**
     * Specifies the relative insets in pixels for the drawable at the
     * specified index.
     *
     * @param index the index of the layer to adjust
     * @param s number of pixels to inset from the start bound
     * @param t number of pixels to inset from the top bound
     * @param e number of pixels to inset from the end bound
     * @param b number of pixels to inset from the bottom bound
     *
     * @attr ref android.R.styleable#LayerDrawableItem_start
     * @attr ref android.R.styleable#LayerDrawableItem_top
     * @attr ref android.R.styleable#LayerDrawableItem_end
     * @attr ref android.R.styleable#LayerDrawableItem_bottom
     */
    public void setLayerInsetRelative(int index, int s, int t, int e, int b) {
        setLayerInsetInternal(index, 0, t, 0, b, s, e);
    }

    
Params:
  • index – the index of the layer to adjust
  • l – number of pixels to inset from the left bound
@attrref android.R.styleable#LayerDrawableItem_left
/**
     * @param index the index of the layer to adjust
     * @param l number of pixels to inset from the left bound
     * @attr ref android.R.styleable#LayerDrawableItem_left
     */
    public void setLayerInsetLeft(int index, int l) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        childDrawable.mInsetL = l;
    }

    
Params:
  • index – the index of the layer
Returns:number of pixels to inset from the left bound
@attrref android.R.styleable#LayerDrawableItem_left
/**
     * @param index the index of the layer
     * @return number of pixels to inset from the left bound
     * @attr ref android.R.styleable#LayerDrawableItem_left
     */
    public int getLayerInsetLeft(int index) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        return childDrawable.mInsetL;
    }

    
Params:
  • index – the index of the layer to adjust
  • r – number of pixels to inset from the right bound
@attrref android.R.styleable#LayerDrawableItem_right
/**
     * @param index the index of the layer to adjust
     * @param r number of pixels to inset from the right bound
     * @attr ref android.R.styleable#LayerDrawableItem_right
     */
    public void setLayerInsetRight(int index, int r) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        childDrawable.mInsetR = r;
    }

    
Params:
  • index – the index of the layer
Returns:number of pixels to inset from the right bound
@attrref android.R.styleable#LayerDrawableItem_right
/**
     * @param index the index of the layer
     * @return number of pixels to inset from the right bound
     * @attr ref android.R.styleable#LayerDrawableItem_right
     */
    public int getLayerInsetRight(int index) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        return childDrawable.mInsetR;
    }

    
Params:
  • index – the index of the layer to adjust
  • t – number of pixels to inset from the top bound
@attrref android.R.styleable#LayerDrawableItem_top
/**
     * @param index the index of the layer to adjust
     * @param t number of pixels to inset from the top bound
     * @attr ref android.R.styleable#LayerDrawableItem_top
     */
    public void setLayerInsetTop(int index, int t) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        childDrawable.mInsetT = t;
    }

    
Params:
  • index – the index of the layer
Returns:number of pixels to inset from the top bound
@attrref android.R.styleable#LayerDrawableItem_top
/**
     * @param index the index of the layer
     * @return number of pixels to inset from the top bound
     * @attr ref android.R.styleable#LayerDrawableItem_top
     */
    public int getLayerInsetTop(int index) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        return childDrawable.mInsetT;
    }

    
Params:
  • index – the index of the layer to adjust
  • b – number of pixels to inset from the bottom bound
@attrref android.R.styleable#LayerDrawableItem_bottom
/**
     * @param index the index of the layer to adjust
     * @param b number of pixels to inset from the bottom bound
     * @attr ref android.R.styleable#LayerDrawableItem_bottom
     */
    public void setLayerInsetBottom(int index, int b) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        childDrawable.mInsetB = b;
    }

    
Params:
  • index – the index of the layer
Returns:number of pixels to inset from the bottom bound
@attrref android.R.styleable#LayerDrawableItem_bottom
/**
     * @param index the index of the layer
     * @return number of pixels to inset from the bottom bound
     * @attr ref android.R.styleable#LayerDrawableItem_bottom
     */
    public int getLayerInsetBottom(int index) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        return childDrawable.mInsetB;
    }

    
Params:
  • index – the index of the layer to adjust
  • s – number of pixels to inset from the start bound
@attrref android.R.styleable#LayerDrawableItem_start
/**
     * @param index the index of the layer to adjust
     * @param s number of pixels to inset from the start bound
     * @attr ref android.R.styleable#LayerDrawableItem_start
     */
    public void setLayerInsetStart(int index, int s) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        childDrawable.mInsetS = s;
    }

    
Params:
  • index – the index of the layer
Returns:the number of pixels to inset from the start bound, or INSET_UNDEFINED if not specified
@attrref android.R.styleable#LayerDrawableItem_start
/**
     * @param index the index of the layer
     * @return the number of pixels to inset from the start bound, or
     *         {@link #INSET_UNDEFINED} if not specified
     * @attr ref android.R.styleable#LayerDrawableItem_start
     */
    public int getLayerInsetStart(int index) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        return childDrawable.mInsetS;
    }

    
Params:
  • index – the index of the layer to adjust
  • e – number of pixels to inset from the end bound, or INSET_UNDEFINED if not specified
@attrref android.R.styleable#LayerDrawableItem_end
/**
     * @param index the index of the layer to adjust
     * @param e number of pixels to inset from the end bound, or
     *         {@link #INSET_UNDEFINED} if not specified
     * @attr ref android.R.styleable#LayerDrawableItem_end
     */
    public void setLayerInsetEnd(int index, int e) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        childDrawable.mInsetE = e;
    }

    
Params:
  • index – the index of the layer
Returns:number of pixels to inset from the end bound
@attrref android.R.styleable#LayerDrawableItem_end
/**
     * @param index the index of the layer
     * @return number of pixels to inset from the end bound
     * @attr ref android.R.styleable#LayerDrawableItem_end
     */
    public int getLayerInsetEnd(int index) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        return childDrawable.mInsetE;
    }

    private void setLayerInsetInternal(int index, int l, int t, int r, int b, int s, int e) {
        final ChildDrawable childDrawable = mLayerState.mChildren[index];
        childDrawable.mInsetL = l;
        childDrawable.mInsetT = t;
        childDrawable.mInsetR = r;
        childDrawable.mInsetB = b;
        childDrawable.mInsetS = s;
        childDrawable.mInsetE = e;
    }

    
Specifies how layer padding should affect the bounds of subsequent layers. The default value is PADDING_MODE_NEST. 
Params:
  • mode – padding mode, one of:
           
See Also:
@attrref android.R.styleable#LayerDrawable_paddingMode
/**
     * Specifies how layer padding should affect the bounds of subsequent
     * layers. The default value is {@link #PADDING_MODE_NEST}.
     *
     * @param mode padding mode, one of:
     *            <ul>
     *            <li>{@link #PADDING_MODE_NEST} to nest each layer inside the
     *            padding of the previous layer
     *            <li>{@link #PADDING_MODE_STACK} to stack each layer directly
     *            atop the previous layer
     *            </ul>
     *
     * @see #getPaddingMode()
     * @attr ref android.R.styleable#LayerDrawable_paddingMode
     */
    public void setPaddingMode(int mode) {
        if (mLayerState.mPaddingMode != mode) {
            mLayerState.mPaddingMode = mode;
        }
    }

    
See Also:
Returns:the current padding mode
@attrref android.R.styleable#LayerDrawable_paddingMode
/**
     * @return the current padding mode
     *
     * @see #setPaddingMode(int)
     * @attr ref android.R.styleable#LayerDrawable_paddingMode
     */
    public int getPaddingMode() {
      return mLayerState.mPaddingMode;
    }

    
Temporarily suspends child invalidation.

See Also:
  • resumeChildInvalidation()
/**
     * Temporarily suspends child invalidation.
     *
     * @see #resumeChildInvalidation()
     */
    private void suspendChildInvalidation() {
        mSuspendChildInvalidation = true;
    }

    
Resumes child invalidation after suspension, immediately performing an
invalidation if one was requested by a child during suspension.

See Also:
  • suspendChildInvalidation()
/**
     * Resumes child invalidation after suspension, immediately performing an
     * invalidation if one was requested by a child during suspension.
     *
     * @see #suspendChildInvalidation()
     */
    private void resumeChildInvalidation() {
        mSuspendChildInvalidation = false;

        if (mChildRequestedInvalidation) {
            mChildRequestedInvalidation = false;
            invalidateSelf();
        }
    }

    @Override
    public void invalidateDrawable(@NonNull Drawable who) {
        if (mSuspendChildInvalidation) {
            mChildRequestedInvalidation = true;
        } else {
            // This may have been called as the result of a tint changing, in
            // which case we may need to refresh the cached statefulness or
            // opacity.
            mLayerState.invalidateCache();

            invalidateSelf();
        }
    }

    @Override
    public void scheduleDrawable(@NonNull Drawable who, @NonNull Runnable what, long when) {
        scheduleSelf(what, when);
    }

    @Override
    public void unscheduleDrawable(@NonNull Drawable who, @NonNull Runnable what) {
        unscheduleSelf(what);
    }

    @Override
    public void draw(Canvas canvas) {
        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final Drawable dr = array[i].mDrawable;
            if (dr != null) {
                dr.draw(canvas);
            }
        }
    }

    @Override
    public @Config int getChangingConfigurations() {
        return super.getChangingConfigurations() | mLayerState.getChangingConfigurations();
    }

    @Override
    public boolean getPadding(Rect padding) {
        final LayerState layerState = mLayerState;
        if (layerState.mPaddingMode == PADDING_MODE_NEST) {
            computeNestedPadding(padding);
        } else {
            computeStackedPadding(padding);
        }

        final int paddingT = layerState.mPaddingTop;
        final int paddingB = layerState.mPaddingBottom;

        // Resolve padding for RTL. Relative padding overrides absolute
        // padding.
        final boolean isLayoutRtl = getLayoutDirection() == LayoutDirection.RTL;
        final int paddingRtlL = isLayoutRtl ? layerState.mPaddingEnd : layerState.mPaddingStart;
        final int paddingRtlR = isLayoutRtl ? layerState.mPaddingStart : layerState.mPaddingEnd;
        final int paddingL = paddingRtlL >= 0 ? paddingRtlL : layerState.mPaddingLeft;
        final int paddingR = paddingRtlR >= 0 ? paddingRtlR : layerState.mPaddingRight;

        // If padding was explicitly specified (e.g. not -1) then override the
        // computed padding in that dimension.
        if (paddingL >= 0) {
            padding.left = paddingL;
        }

        if (paddingT >= 0) {
            padding.top = paddingT;
        }

        if (paddingR >= 0) {
            padding.right = paddingR;
        }

        if (paddingB >= 0) {
            padding.bottom = paddingB;
        }

        return padding.left != 0 || padding.top != 0 || padding.right != 0 || padding.bottom != 0;
    }

    
Sets the absolute padding.

 If padding in a dimension is specified as -1, the resolved padding will use the value computed according to the padding mode (see setPaddingMode(int)). 
 Calling this method clears any relative padding values previously set using setPaddingRelative(int, int, int, int). 
Params:
  • left – the left padding in pixels, or -1 to use computed padding
  • top – the top padding in pixels, or -1 to use computed padding
  • right – the right padding in pixels, or -1 to use computed padding
  • bottom – the bottom padding in pixels, or -1 to use computed
              padding
See Also:
@attrref android.R.styleable#LayerDrawable_paddingLeft
@attrref android.R.styleable#LayerDrawable_paddingTop
@attrref android.R.styleable#LayerDrawable_paddingRight
@attrref android.R.styleable#LayerDrawable_paddingBottom
/**
     * Sets the absolute padding.
     * <p>
     * If padding in a dimension is specified as {@code -1}, the resolved
     * padding will use the value computed according to the padding mode (see
     * {@link #setPaddingMode(int)}).
     * <p>
     * Calling this method clears any relative padding values previously set
     * using {@link #setPaddingRelative(int, int, int, int)}.
     *
     * @param left the left padding in pixels, or -1 to use computed padding
     * @param top the top padding in pixels, or -1 to use computed padding
     * @param right the right padding in pixels, or -1 to use computed padding
     * @param bottom the bottom padding in pixels, or -1 to use computed
     *               padding
     * @attr ref android.R.styleable#LayerDrawable_paddingLeft
     * @attr ref android.R.styleable#LayerDrawable_paddingTop
     * @attr ref android.R.styleable#LayerDrawable_paddingRight
     * @attr ref android.R.styleable#LayerDrawable_paddingBottom
     * @see #setPaddingRelative(int, int, int, int)
     */
    public void setPadding(int left, int top, int right, int bottom) {
        final LayerState layerState = mLayerState;
        layerState.mPaddingLeft = left;
        layerState.mPaddingTop = top;
        layerState.mPaddingRight = right;
        layerState.mPaddingBottom = bottom;

        // Clear relative padding values.
        layerState.mPaddingStart = -1;
        layerState.mPaddingEnd = -1;
    }

    
Sets the relative padding.

 If padding in a dimension is specified as -1, the resolved padding will use the value computed according to the padding mode (see setPaddingMode(int)). 
 Calling this method clears any absolute padding values previously set using setPadding(int, int, int, int). 
Params:
  • start – the start padding in pixels, or -1 to use computed padding
  • top – the top padding in pixels, or -1 to use computed padding
  • end – the end padding in pixels, or -1 to use computed padding
  • bottom – the bottom padding in pixels, or -1 to use computed
              padding
See Also:
@attrref android.R.styleable#LayerDrawable_paddingStart
@attrref android.R.styleable#LayerDrawable_paddingTop
@attrref android.R.styleable#LayerDrawable_paddingEnd
@attrref android.R.styleable#LayerDrawable_paddingBottom
/**
     * Sets the relative padding.
     * <p>
     * If padding in a dimension is specified as {@code -1}, the resolved
     * padding will use the value computed according to the padding mode (see
     * {@link #setPaddingMode(int)}).
     * <p>
     * Calling this method clears any absolute padding values previously set
     * using {@link #setPadding(int, int, int, int)}.
     *
     * @param start the start padding in pixels, or -1 to use computed padding
     * @param top the top padding in pixels, or -1 to use computed padding
     * @param end the end padding in pixels, or -1 to use computed padding
     * @param bottom the bottom padding in pixels, or -1 to use computed
     *               padding
     * @attr ref android.R.styleable#LayerDrawable_paddingStart
     * @attr ref android.R.styleable#LayerDrawable_paddingTop
     * @attr ref android.R.styleable#LayerDrawable_paddingEnd
     * @attr ref android.R.styleable#LayerDrawable_paddingBottom
     * @see #setPadding(int, int, int, int)
     */
    public void setPaddingRelative(int start, int top, int end, int bottom) {
        final LayerState layerState = mLayerState;
        layerState.mPaddingStart = start;
        layerState.mPaddingTop = top;
        layerState.mPaddingEnd = end;
        layerState.mPaddingBottom = bottom;

        // Clear absolute padding values.
        layerState.mPaddingLeft = -1;
        layerState.mPaddingRight = -1;
    }

    
Returns the left padding in pixels.

 A return value of -1 means there is no explicit padding set for this dimension. As a result, the value for this dimension returned by getPadding(Rect) will be computed from the child layers according to the padding mode (see getPaddingMode(). 
See Also:
Returns:the left padding in pixels, or -1 if not explicitly specified
/**
     * Returns the left padding in pixels.
     * <p>
     * A return value of {@code -1} means there is no explicit padding set for
     * this dimension. As a result, the value for this dimension returned by
     * {@link #getPadding(Rect)} will be computed from the child layers
     * according to the padding mode (see {@link #getPaddingMode()}.
     *
     * @return the left padding in pixels, or -1 if not explicitly specified
     * @see #setPadding(int, int, int, int)
     * @see #getPadding(Rect)
     */
    public int getLeftPadding() {
        return mLayerState.mPaddingLeft;
    }

    
Returns the right padding in pixels.

 A return value of -1 means there is no explicit padding set for this dimension. As a result, the value for this dimension returned by getPadding(Rect) will be computed from the child layers according to the padding mode (see getPaddingMode(). 
See Also:
Returns:the right padding in pixels, or -1 if not explicitly specified
/**
     * Returns the right padding in pixels.
     * <p>
     * A return value of {@code -1} means there is no explicit padding set for
     * this dimension. As a result, the value for this dimension returned by
     * {@link #getPadding(Rect)} will be computed from the child layers
     * according to the padding mode (see {@link #getPaddingMode()}.
     *
     * @return the right padding in pixels, or -1 if not explicitly specified
     * @see #setPadding(int, int, int, int)
     * @see #getPadding(Rect)
     */
    public int getRightPadding() {
        return mLayerState.mPaddingRight;
    }

    
Returns the start padding in pixels.

 A return value of -1 means there is no explicit padding set for this dimension. As a result, the value for this dimension returned by getPadding(Rect) will be computed from the child layers according to the padding mode (see getPaddingMode(). 
See Also:
Returns:the start padding in pixels, or -1 if not explicitly specified
/**
     * Returns the start padding in pixels.
     * <p>
     * A return value of {@code -1} means there is no explicit padding set for
     * this dimension. As a result, the value for this dimension returned by
     * {@link #getPadding(Rect)} will be computed from the child layers
     * according to the padding mode (see {@link #getPaddingMode()}.
     *
     * @return the start padding in pixels, or -1 if not explicitly specified
     * @see #setPaddingRelative(int, int, int, int)
     * @see #getPadding(Rect)
     */
    public int getStartPadding() {
        return mLayerState.mPaddingStart;
    }

    
Returns the end padding in pixels.

 A return value of -1 means there is no explicit padding set for this dimension. As a result, the value for this dimension returned by getPadding(Rect) will be computed from the child layers according to the padding mode (see getPaddingMode(). 
See Also:
Returns:the end padding in pixels, or -1 if not explicitly specified
/**
     * Returns the end padding in pixels.
     * <p>
     * A return value of {@code -1} means there is no explicit padding set for
     * this dimension. As a result, the value for this dimension returned by
     * {@link #getPadding(Rect)} will be computed from the child layers
     * according to the padding mode (see {@link #getPaddingMode()}.
     *
     * @return the end padding in pixels, or -1 if not explicitly specified
     * @see #setPaddingRelative(int, int, int, int)
     * @see #getPadding(Rect)
     */
    public int getEndPadding() {
        return mLayerState.mPaddingEnd;
    }

    
Returns the top padding in pixels.

 A return value of -1 means there is no explicit padding set for this dimension. As a result, the value for this dimension returned by getPadding(Rect) will be computed from the child layers according to the padding mode (see getPaddingMode(). 
See Also:
Returns:the top padding in pixels, or -1 if not explicitly specified
/**
     * Returns the top padding in pixels.
     * <p>
     * A return value of {@code -1} means there is no explicit padding set for
     * this dimension. As a result, the value for this dimension returned by
     * {@link #getPadding(Rect)} will be computed from the child layers
     * according to the padding mode (see {@link #getPaddingMode()}.
     *
     * @return the top padding in pixels, or -1 if not explicitly specified
     * @see #setPadding(int, int, int, int)
     * @see #setPaddingRelative(int, int, int, int)
     * @see #getPadding(Rect)
     */
    public int getTopPadding() {
        return mLayerState.mPaddingTop;
    }

    
Returns the bottom padding in pixels.

 A return value of -1 means there is no explicit padding set for this dimension. As a result, the value for this dimension returned by getPadding(Rect) will be computed from the child layers according to the padding mode (see getPaddingMode(). 
See Also:
Returns:the bottom padding in pixels, or -1 if not explicitly specified
/**
     * Returns the bottom padding in pixels.
     * <p>
     * A return value of {@code -1} means there is no explicit padding set for
     * this dimension. As a result, the value for this dimension returned by
     * {@link #getPadding(Rect)} will be computed from the child layers
     * according to the padding mode (see {@link #getPaddingMode()}.
     *
     * @return the bottom padding in pixels, or -1 if not explicitly specified
     * @see #setPadding(int, int, int, int)
     * @see #setPaddingRelative(int, int, int, int)
     * @see #getPadding(Rect)
     */
    public int getBottomPadding() {
        return mLayerState.mPaddingBottom;
    }

    private void computeNestedPadding(Rect padding) {
        padding.left = 0;
        padding.top = 0;
        padding.right = 0;
        padding.bottom = 0;

        // Add all the padding.
        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            refreshChildPadding(i, array[i]);

            padding.left += mPaddingL[i];
            padding.top += mPaddingT[i];
            padding.right += mPaddingR[i];
            padding.bottom += mPaddingB[i];
        }
    }

    private void computeStackedPadding(Rect padding) {
        padding.left = 0;
        padding.top = 0;
        padding.right = 0;
        padding.bottom = 0;

        // Take the max padding.
        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            refreshChildPadding(i, array[i]);

            padding.left = Math.max(padding.left, mPaddingL[i]);
            padding.top = Math.max(padding.top, mPaddingT[i]);
            padding.right = Math.max(padding.right, mPaddingR[i]);
            padding.bottom = Math.max(padding.bottom, mPaddingB[i]);
        }
    }

    
Populates outline with the first available (non-empty) layer outline.

Params:
  • outline – Outline in which to place the first available layer outline
/**
     * Populates <code>outline</code> with the first available (non-empty) layer outline.
     *
     * @param outline Outline in which to place the first available layer outline
     */
    @Override
    public void getOutline(@NonNull Outline outline) {
        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final Drawable dr = array[i].mDrawable;
            if (dr != null) {
                dr.getOutline(outline);
                if (!outline.isEmpty()) {
                    return;
                }
            }
        }
    }

    @Override
    public void setHotspot(float x, float y) {
        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final Drawable dr = array[i].mDrawable;
            if (dr != null) {
                dr.setHotspot(x, y);
            }
        }
    }

    @Override
    public void setHotspotBounds(int left, int top, int right, int bottom) {
        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final Drawable dr = array[i].mDrawable;
            if (dr != null) {
                dr.setHotspotBounds(left, top, right, bottom);
            }
        }

        if (mHotspotBounds == null) {
            mHotspotBounds = new Rect(left, top, right, bottom);
        } else {
            mHotspotBounds.set(left, top, right, bottom);
        }
    }

    @Override
    public void getHotspotBounds(Rect outRect) {
        if (mHotspotBounds != null) {
            outRect.set(mHotspotBounds);
        } else {
            super.getHotspotBounds(outRect);
        }
    }

    @Override
    public boolean setVisible(boolean visible, boolean restart) {
        final boolean changed = super.setVisible(visible, restart);
        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final Drawable dr = array[i].mDrawable;
            if (dr != null) {
                dr.setVisible(visible, restart);
            }
        }

        return changed;
    }

    @Override
    public void setDither(boolean dither) {
        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final Drawable dr = array[i].mDrawable;
            if (dr != null) {
                dr.setDither(dither);
            }
        }
    }

    @Override
    public void setAlpha(int alpha) {
        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final Drawable dr = array[i].mDrawable;
            if (dr != null) {
                dr.setAlpha(alpha);
            }
        }
    }

    @Override
    public int getAlpha() {
        final Drawable dr = getFirstNonNullDrawable();
        if (dr != null) {
            return dr.getAlpha();
        } else {
            return super.getAlpha();
        }
    }

    @Override
    public void setColorFilter(ColorFilter colorFilter) {
        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final Drawable dr = array[i].mDrawable;
            if (dr != null) {
                dr.setColorFilter(colorFilter);
            }
        }
    }

    @Override
    public void setTintList(ColorStateList tint) {
        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final Drawable dr = array[i].mDrawable;
            if (dr != null) {
                dr.setTintList(tint);
            }
        }
    }

    @Override
    public void setTintMode(Mode tintMode) {
        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final Drawable dr = array[i].mDrawable;
            if (dr != null) {
                dr.setTintMode(tintMode);
            }
        }
    }

    private Drawable getFirstNonNullDrawable() {
        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final Drawable dr = array[i].mDrawable;
            if (dr != null) {
                return dr;
            }
        }
        return null;
    }

    
Sets the opacity of this drawable directly instead of collecting the
states from the layers.

Params:
See Also:
/**
     * Sets the opacity of this drawable directly instead of collecting the
     * states from the layers.
     *
     * @param opacity The opacity to use, or {@link PixelFormat#UNKNOWN
     *            PixelFormat.UNKNOWN} for the default behavior
     * @see PixelFormat#UNKNOWN
     * @see PixelFormat#TRANSLUCENT
     * @see PixelFormat#TRANSPARENT
     * @see PixelFormat#OPAQUE
     */
    public void setOpacity(int opacity) {
        mLayerState.mOpacityOverride = opacity;
    }

    @Override
    public int getOpacity() {
        if (mLayerState.mOpacityOverride != PixelFormat.UNKNOWN) {
            return mLayerState.mOpacityOverride;
        }
        return mLayerState.getOpacity();
    }

    @Override
    public void setAutoMirrored(boolean mirrored) {
        mLayerState.mAutoMirrored = mirrored;

        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final Drawable dr = array[i].mDrawable;
            if (dr != null) {
                dr.setAutoMirrored(mirrored);
            }
        }
    }

    @Override
    public boolean isAutoMirrored() {
        return mLayerState.mAutoMirrored;
    }

    @Override
    public void jumpToCurrentState() {
        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final Drawable dr = array[i].mDrawable;
            if (dr != null) {
                dr.jumpToCurrentState();
            }
        }
    }

    @Override
    public boolean isStateful() {
        return mLayerState.isStateful();
    }

    
@hide
/** @hide */
    @Override
    public boolean hasFocusStateSpecified() {
        return mLayerState.hasFocusStateSpecified();
    }

    @Override
    protected boolean onStateChange(int[] state) {
        boolean changed = false;

        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final Drawable dr = array[i].mDrawable;
            if (dr != null && dr.isStateful() && dr.setState(state)) {
                refreshChildPadding(i, array[i]);
                changed = true;
            }
        }

        if (changed) {
            updateLayerBounds(getBounds());
        }

        return changed;
    }

    @Override
    protected boolean onLevelChange(int level) {
        boolean changed = false;

        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final Drawable dr = array[i].mDrawable;
            if (dr != null && dr.setLevel(level)) {
                refreshChildPadding(i, array[i]);
                changed = true;
            }
        }

        if (changed) {
            updateLayerBounds(getBounds());
        }

        return changed;
    }

    @Override
    protected void onBoundsChange(Rect bounds) {
        updateLayerBounds(bounds);
    }

    private void updateLayerBounds(Rect bounds) {
        try {
            suspendChildInvalidation();
            updateLayerBoundsInternal(bounds);
        } finally {
            resumeChildInvalidation();
        }
    }

    private void updateLayerBoundsInternal(Rect bounds) {
        int paddingL = 0;
        int paddingT = 0;
        int paddingR = 0;
        int paddingB = 0;

        final Rect outRect = mTmpOutRect;
        final int layoutDirection = getLayoutDirection();
        final boolean isLayoutRtl = layoutDirection == LayoutDirection.RTL;
        final boolean isPaddingNested = mLayerState.mPaddingMode == PADDING_MODE_NEST;
        final ChildDrawable[] array = mLayerState.mChildren;

        for (int i = 0, count = mLayerState.mNumChildren; i < count; i++) {
            final ChildDrawable r = array[i];
            final Drawable d = r.mDrawable;
            if (d == null) {
                continue;
            }

            final int insetT = r.mInsetT;
            final int insetB = r.mInsetB;

            // Resolve insets for RTL. Relative insets override absolute
            // insets.
            final int insetRtlL = isLayoutRtl ? r.mInsetE : r.mInsetS;
            final int insetRtlR = isLayoutRtl ? r.mInsetS : r.mInsetE;
            final int insetL = insetRtlL == INSET_UNDEFINED ? r.mInsetL : insetRtlL;
            final int insetR = insetRtlR == INSET_UNDEFINED ? r.mInsetR : insetRtlR;

            // Establish containing region based on aggregate padding and
            // requested insets for the current layer.
            final Rect container = mTmpContainer;
            container.set(bounds.left + insetL + paddingL, bounds.top + insetT + paddingT,
                    bounds.right - insetR - paddingR, bounds.bottom - insetB - paddingB);

            // Compute a reasonable default gravity based on the intrinsic and
            // explicit dimensions, if specified.
            final int intrinsicW = d.getIntrinsicWidth();
            final int intrinsicH = d.getIntrinsicHeight();
            final int layerW = r.mWidth;
            final int layerH = r.mHeight;
            final int gravity = resolveGravity(r.mGravity, layerW, layerH, intrinsicW, intrinsicH);

            // Explicit dimensions override intrinsic dimensions.
            final int resolvedW = layerW < 0 ? intrinsicW : layerW;
            final int resolvedH = layerH < 0 ? intrinsicH : layerH;
            Gravity.apply(gravity, resolvedW, resolvedH, container, outRect, layoutDirection);
            d.setBounds(outRect);

            if (isPaddingNested) {
                paddingL += mPaddingL[i];
                paddingR += mPaddingR[i];
                paddingT += mPaddingT[i];
                paddingB += mPaddingB[i];
            }
        }
    }

    
Resolves layer gravity given explicit gravity and dimensions.


If the client hasn't specified a gravity but has specified an explicit
dimension, defaults to START or TOP. Otherwise, defaults to FILL to
preserve legacy behavior.

Params:
  • gravity – layer gravity
  • width – width of the layer if set, -1 otherwise
  • height – height of the layer if set, -1 otherwise
Returns:the default gravity for the layer
/**
     * Resolves layer gravity given explicit gravity and dimensions.
     * <p>
     * If the client hasn't specified a gravity but has specified an explicit
     * dimension, defaults to START or TOP. Otherwise, defaults to FILL to
     * preserve legacy behavior.
     *
     * @param gravity layer gravity
     * @param width width of the layer if set, -1 otherwise
     * @param height height of the layer if set, -1 otherwise
     * @return the default gravity for the layer
     */
    private static int resolveGravity(int gravity, int width, int height,
            int intrinsicWidth, int intrinsicHeight) {
        if (!Gravity.isHorizontal(gravity)) {
            if (width < 0) {
                gravity |= Gravity.FILL_HORIZONTAL;
            } else {
                gravity |= Gravity.START;
            }
        }

        if (!Gravity.isVertical(gravity)) {
            if (height < 0) {
                gravity |= Gravity.FILL_VERTICAL;
            } else {
                gravity |= Gravity.TOP;
            }
        }

        // If a dimension if not specified, either implicitly or explicitly,
        // force FILL for that dimension's gravity. This ensures that colors
        // are handled correctly and ensures backward compatibility.
        if (width < 0 && intrinsicWidth < 0) {
            gravity |= Gravity.FILL_HORIZONTAL;
        }

        if (height < 0 && intrinsicHeight < 0) {
            gravity |= Gravity.FILL_VERTICAL;
        }

        return gravity;
    }

    @Override
    public int getIntrinsicWidth() {
        int width = -1;
        int padL = 0;
        int padR = 0;

        final boolean nest = mLayerState.mPaddingMode == PADDING_MODE_NEST;
        final boolean isLayoutRtl = getLayoutDirection() == LayoutDirection.RTL;
        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final ChildDrawable r = array[i];
            if (r.mDrawable == null) {
                continue;
            }

            // Take the resolved layout direction into account. If start / end
            // padding are defined, they will be resolved (hence overriding) to
            // left / right or right / left depending on the resolved layout
            // direction. If start / end padding are not defined, use the
            // left / right ones.
            final int insetRtlL = isLayoutRtl ? r.mInsetE : r.mInsetS;
            final int insetRtlR = isLayoutRtl ? r.mInsetS : r.mInsetE;
            final int insetL = insetRtlL == INSET_UNDEFINED ? r.mInsetL : insetRtlL;
            final int insetR = insetRtlR == INSET_UNDEFINED ? r.mInsetR : insetRtlR;

            // Don't apply padding and insets for children that don't have
            // an intrinsic dimension.
            final int minWidth = r.mWidth < 0 ? r.mDrawable.getIntrinsicWidth() : r.mWidth;
            final int w = minWidth < 0 ? -1 : minWidth + insetL + insetR + padL + padR;
            if (w > width) {
                width = w;
            }

            if (nest) {
                padL += mPaddingL[i];
                padR += mPaddingR[i];
            }
        }

        return width;
    }

    @Override
    public int getIntrinsicHeight() {
        int height = -1;
        int padT = 0;
        int padB = 0;

        final boolean nest = mLayerState.mPaddingMode == PADDING_MODE_NEST;
        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final ChildDrawable r = array[i];
            if (r.mDrawable == null) {
                continue;
            }

            // Don't apply padding and insets for children that don't have
            // an intrinsic dimension.
            final int minHeight = r.mHeight < 0 ? r.mDrawable.getIntrinsicHeight() : r.mHeight;
            final int h = minHeight < 0 ? -1 : minHeight + r.mInsetT + r.mInsetB + padT + padB;
            if (h > height) {
                height = h;
            }

            if (nest) {
                padT += mPaddingT[i];
                padB += mPaddingB[i];
            }
        }

        return height;
    }

    
Refreshes the cached padding values for the specified child.

Returns:true if the child's padding has changed
/**
     * Refreshes the cached padding values for the specified child.
     *
     * @return true if the child's padding has changed
     */
    private boolean refreshChildPadding(int i, ChildDrawable r) {
        if (r.mDrawable != null) {
            final Rect rect = mTmpRect;
            r.mDrawable.getPadding(rect);
            if (rect.left != mPaddingL[i] || rect.top != mPaddingT[i]
                    || rect.right != mPaddingR[i] || rect.bottom != mPaddingB[i]) {
                mPaddingL[i] = rect.left;
                mPaddingT[i] = rect.top;
                mPaddingR[i] = rect.right;
                mPaddingB[i] = rect.bottom;
                return true;
            }
        }
        return false;
    }

    
Ensures the child padding caches are large enough.

/**
     * Ensures the child padding caches are large enough.
     */
    void ensurePadding() {
        final int N = mLayerState.mNumChildren;
        if (mPaddingL != null && mPaddingL.length >= N) {
            return;
        }

        mPaddingL = new int[N];
        mPaddingT = new int[N];
        mPaddingR = new int[N];
        mPaddingB = new int[N];
    }

    void refreshPadding() {
        final int N = mLayerState.mNumChildren;
        final ChildDrawable[] array = mLayerState.mChildren;
        for (int i = 0; i < N; i++) {
            refreshChildPadding(i, array[i]);
        }
    }

    @Override
    public ConstantState getConstantState() {
        if (mLayerState.canConstantState()) {
            mLayerState.mChangingConfigurations = getChangingConfigurations();
            return mLayerState;
        }
        return null;
    }

    @Override
    public Drawable mutate() {
        if (!mMutated && super.mutate() == this) {
            mLayerState = createConstantState(mLayerState, null);
            final ChildDrawable[] array = mLayerState.mChildren;
            final int N = mLayerState.mNumChildren;
            for (int i = 0; i < N; i++) {
                final Drawable dr = array[i].mDrawable;
                if (dr != null) {
                    dr.mutate();
                }
            }
            mMutated = true;
        }
        return this;
    }

    
@hide
/**
     * @hide
     */
    public void clearMutated() {
        super.clearMutated();

        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final Drawable dr = array[i].mDrawable;
            if (dr != null) {
                dr.clearMutated();
            }
        }
        mMutated = false;
    }

    @Override
    public boolean onLayoutDirectionChanged(@View.ResolvedLayoutDir int layoutDirection) {
        boolean changed = false;

        final ChildDrawable[] array = mLayerState.mChildren;
        final int N = mLayerState.mNumChildren;
        for (int i = 0; i < N; i++) {
            final Drawable dr = array[i].mDrawable;
            if (dr != null) {
                changed |= dr.setLayoutDirection(layoutDirection);
            }
        }

        updateLayerBounds(getBounds());
        return changed;
    }

    static class ChildDrawable {
        public Drawable mDrawable;
        public int[] mThemeAttrs;
        public int mDensity = DisplayMetrics.DENSITY_DEFAULT;
        public int mInsetL, mInsetT, mInsetR, mInsetB;
        public int mInsetS = INSET_UNDEFINED;
        public int mInsetE = INSET_UNDEFINED;
        public int mWidth = -1;
        public int mHeight = -1;
        public int mGravity = Gravity.NO_GRAVITY;
        public int mId = View.NO_ID;

        ChildDrawable(int density) {
            mDensity = density;
        }

        ChildDrawable(@NonNull ChildDrawable orig, @NonNull LayerDrawable owner,
                @Nullable Resources res) {
            final Drawable dr = orig.mDrawable;
            final Drawable clone;
            if (dr != null) {
                final ConstantState cs = dr.getConstantState();
                if (cs == null) {
                    clone = dr;
                    if (dr.getCallback() != null) {
                        // This drawable already has an owner.
                        Log.w(LOG_TAG, "Invalid drawable added to LayerDrawable! Drawable already "
                                + "belongs to another owner but does not expose a constant state.",
                                new RuntimeException());
                    }
                } else if (res != null) {
                    clone = cs.newDrawable(res);
                } else {
                    clone = cs.newDrawable();
                }
                clone.setLayoutDirection(dr.getLayoutDirection());
                clone.setBounds(dr.getBounds());
                clone.setLevel(dr.getLevel());

                // Set the callback last to prevent invalidation from
                // propagating before the constant state has been set.
                clone.setCallback(owner);
            } else {
                clone = null;
            }

            mDrawable = clone;
            mThemeAttrs = orig.mThemeAttrs;
            mInsetL = orig.mInsetL;
            mInsetT = orig.mInsetT;
            mInsetR = orig.mInsetR;
            mInsetB = orig.mInsetB;
            mInsetS = orig.mInsetS;
            mInsetE = orig.mInsetE;
            mWidth = orig.mWidth;
            mHeight = orig.mHeight;
            mGravity = orig.mGravity;
            mId = orig.mId;

            mDensity = Drawable.resolveDensity(res, orig.mDensity);
            if (orig.mDensity != mDensity) {
                applyDensityScaling(orig.mDensity, mDensity);
            }
        }

        public boolean canApplyTheme() {
            return mThemeAttrs != null
                    || (mDrawable != null && mDrawable.canApplyTheme());
        }

        public final void setDensity(int targetDensity) {
            if (mDensity != targetDensity) {
                final int sourceDensity = mDensity;
                mDensity = targetDensity;

                applyDensityScaling(sourceDensity, targetDensity);
            }
        }

        private void applyDensityScaling(int sourceDensity, int targetDensity) {
            mInsetL = Drawable.scaleFromDensity(mInsetL, sourceDensity, targetDensity, false);
            mInsetT = Drawable.scaleFromDensity(mInsetT, sourceDensity, targetDensity, false);
            mInsetR = Drawable.scaleFromDensity(mInsetR, sourceDensity, targetDensity, false);
            mInsetB = Drawable.scaleFromDensity(mInsetB, sourceDensity, targetDensity, false);
            if (mInsetS != INSET_UNDEFINED) {
                mInsetS = Drawable.scaleFromDensity(mInsetS, sourceDensity, targetDensity, false);
            }
            if (mInsetE != INSET_UNDEFINED) {
                mInsetE = Drawable.scaleFromDensity(mInsetE, sourceDensity, targetDensity, false);
            }
            if (mWidth > 0) {
                mWidth = Drawable.scaleFromDensity(mWidth, sourceDensity, targetDensity, true);
            }
            if (mHeight > 0) {
                mHeight = Drawable.scaleFromDensity(mHeight, sourceDensity, targetDensity, true);
            }
        }
    }

    static class LayerState extends ConstantState {
        private int[] mThemeAttrs;

        int mNumChildren;
        ChildDrawable[] mChildren;

        int mDensity;

        // These values all correspond to mDensity.
        int mPaddingTop = -1;
        int mPaddingBottom = -1;
        int mPaddingLeft = -1;
        int mPaddingRight = -1;
        int mPaddingStart = -1;
        int mPaddingEnd = -1;
        int mOpacityOverride = PixelFormat.UNKNOWN;

        @Config int mChangingConfigurations;
        @Config int mChildrenChangingConfigurations;

        private boolean mCheckedOpacity;
        private int mOpacity;

        private boolean mCheckedStateful;
        private boolean mIsStateful;

        private boolean mAutoMirrored = false;

        private int mPaddingMode = PADDING_MODE_NEST;

        LayerState(@Nullable LayerState orig, @NonNull LayerDrawable owner,
                @Nullable Resources res) {
            mDensity = Drawable.resolveDensity(res, orig != null ? orig.mDensity : 0);

            if (orig != null) {
                final ChildDrawable[] origChildDrawable = orig.mChildren;
                final int N = orig.mNumChildren;

                mNumChildren = N;
                mChildren = new ChildDrawable[N];

                mChangingConfigurations = orig.mChangingConfigurations;
                mChildrenChangingConfigurations = orig.mChildrenChangingConfigurations;

                for (int i = 0; i < N; i++) {
                    final ChildDrawable or = origChildDrawable[i];
                    mChildren[i] = new ChildDrawable(or, owner, res);
                }

                mCheckedOpacity = orig.mCheckedOpacity;
                mOpacity = orig.mOpacity;
                mCheckedStateful = orig.mCheckedStateful;
                mIsStateful = orig.mIsStateful;
                mAutoMirrored = orig.mAutoMirrored;
                mPaddingMode = orig.mPaddingMode;
                mThemeAttrs = orig.mThemeAttrs;
                mPaddingTop = orig.mPaddingTop;
                mPaddingBottom = orig.mPaddingBottom;
                mPaddingLeft = orig.mPaddingLeft;
                mPaddingRight = orig.mPaddingRight;
                mPaddingStart = orig.mPaddingStart;
                mPaddingEnd = orig.mPaddingEnd;
                mOpacityOverride = orig.mOpacityOverride;

                if (orig.mDensity != mDensity) {
                    applyDensityScaling(orig.mDensity, mDensity);
                }
            } else {
                mNumChildren = 0;
                mChildren = null;
            }
        }

        public final void setDensity(int targetDensity) {
            if (mDensity != targetDensity) {
                final int sourceDensity = mDensity;
                mDensity = targetDensity;

                onDensityChanged(sourceDensity, targetDensity);
            }
        }

        protected void onDensityChanged(int sourceDensity, int targetDensity) {
            applyDensityScaling(sourceDensity, targetDensity);
        }

        private void applyDensityScaling(int sourceDensity, int targetDensity) {
            if (mPaddingLeft > 0) {
                mPaddingLeft = Drawable.scaleFromDensity(
                        mPaddingLeft, sourceDensity, targetDensity, false);
            }
            if (mPaddingTop > 0) {
                mPaddingTop = Drawable.scaleFromDensity(
                        mPaddingTop, sourceDensity, targetDensity, false);
            }
            if (mPaddingRight > 0) {
                mPaddingRight = Drawable.scaleFromDensity(
                        mPaddingRight, sourceDensity, targetDensity, false);
            }
            if (mPaddingBottom > 0) {
                mPaddingBottom = Drawable.scaleFromDensity(
                        mPaddingBottom, sourceDensity, targetDensity, false);
            }
            if (mPaddingStart > 0) {
                mPaddingStart = Drawable.scaleFromDensity(
                        mPaddingStart, sourceDensity, targetDensity, false);
            }
            if (mPaddingEnd > 0) {
                mPaddingEnd = Drawable.scaleFromDensity(
                        mPaddingEnd, sourceDensity, targetDensity, false);
            }
        }

        @Override
        public boolean canApplyTheme() {
            if (mThemeAttrs != null || super.canApplyTheme()) {
                return true;
            }

            final ChildDrawable[] array = mChildren;
            final int N = mNumChildren;
            for (int i = 0; i < N; i++) {
                final ChildDrawable layer = array[i];
                if (layer.canApplyTheme()) {
                    return true;
                }
            }

            return false;
        }

        @Override
        public Drawable newDrawable() {
            return new LayerDrawable(this, null);
        }

        @Override
        public Drawable newDrawable(@Nullable Resources res) {
            return new LayerDrawable(this, res);
        }

        @Override
        public @Config int getChangingConfigurations() {
            return mChangingConfigurations
                    | mChildrenChangingConfigurations;
        }

        public final int getOpacity() {
            if (mCheckedOpacity) {
                return mOpacity;
            }

            final int N = mNumChildren;
            final ChildDrawable[] array = mChildren;

            // Seek to the first non-null drawable.
            int firstIndex = -1;
            for (int i = 0; i < N; i++) {
                if (array[i].mDrawable != null) {
                    firstIndex = i;
                    break;
                }
            }

            int op;
            if (firstIndex >= 0) {
                op = array[firstIndex].mDrawable.getOpacity();
            } else {
                op = PixelFormat.TRANSPARENT;
            }

            // Merge all remaining non-null drawables.
            for (int i = firstIndex + 1; i < N; i++) {
                final Drawable dr = array[i].mDrawable;
                if (dr != null) {
                    op = Drawable.resolveOpacity(op, dr.getOpacity());
                }
            }

            mOpacity = op;
            mCheckedOpacity = true;
            return op;
        }

        public final boolean isStateful() {
            if (mCheckedStateful) {
                return mIsStateful;
            }

            final int N = mNumChildren;
            final ChildDrawable[] array = mChildren;
            boolean isStateful = false;
            for (int i = 0; i < N; i++) {
                final Drawable dr = array[i].mDrawable;
                if (dr != null && dr.isStateful()) {
                    isStateful = true;
                    break;
                }
            }

            mIsStateful = isStateful;
            mCheckedStateful = true;
            return isStateful;
        }

        public final boolean hasFocusStateSpecified() {
            final int N = mNumChildren;
            final ChildDrawable[] array = mChildren;
            for (int i = 0; i < N; i++) {
                final Drawable dr = array[i].mDrawable;
                if (dr != null && dr.hasFocusStateSpecified()) {
                    return true;
                }
            }
            return false;
        }

        public final boolean canConstantState() {
            final ChildDrawable[] array = mChildren;
            final int N = mNumChildren;
            for (int i = 0; i < N; i++) {
                final Drawable dr = array[i].mDrawable;
                if (dr != null && dr.getConstantState() == null) {
                    return false;
                }
            }

            // Don't cache the result, this method is not called very often.
            return true;
        }

        
Invalidates the cached opacity and statefulness.

/**
         * Invalidates the cached opacity and statefulness.
         */
        void invalidateCache() {
            mCheckedOpacity = false;
            mCheckedStateful = false;
        }

    }
}