/*
 * 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.view;

import android.annotation.LayoutRes;
import android.annotation.Nullable;
import android.annotation.SystemService;
import android.content.Context;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.content.res.XmlResourceParser;
import android.graphics.Canvas;
import android.os.Handler;
import android.os.Message;
import android.os.Trace;
import android.util.AttributeSet;
import android.util.Log;
import android.util.TypedValue;
import android.util.Xml;
import android.widget.FrameLayout;

import com.android.internal.R;

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

import java.io.IOException;
import java.lang.reflect.Constructor;
import java.util.HashMap;

Instantiates a layout XML file into its corresponding View objects. It is never used directly. Instead, use Activity.getLayoutInflater() or Context.getSystemService to retrieve a standard LayoutInflater instance that is already hooked up to the current context and correctly configured for the device you are running on. 
 To create a new LayoutInflater with an additional Factory for your own views, you can use cloneInContext to clone an existing ViewFactory, and then call setFactory on it to include your Factory. 

For performance reasons, view inflation relies heavily on pre-processing of
XML files that is done at build time. Therefore, it is not currently possible
to use LayoutInflater with an XmlPullParser over a plain XML file at runtime;
it only works with an XmlPullParser returned from a compiled resource
(R.something file.)
/**
 * Instantiates a layout XML file into its corresponding {@link android.view.View}
 * objects. It is never used directly. Instead, use
 * {@link android.app.Activity#getLayoutInflater()} or
 * {@link Context#getSystemService} to retrieve a standard LayoutInflater instance
 * that is already hooked up to the current context and correctly configured
 * for the device you are running on.
 *
 * <p>
 * To create a new LayoutInflater with an additional {@link Factory} for your
 * own views, you can use {@link #cloneInContext} to clone an existing
 * ViewFactory, and then call {@link #setFactory} on it to include your
 * Factory.
 *
 * <p>
 * For performance reasons, view inflation relies heavily on pre-processing of
 * XML files that is done at build time. Therefore, it is not currently possible
 * to use LayoutInflater with an XmlPullParser over a plain XML file at runtime;
 * it only works with an XmlPullParser returned from a compiled resource
 * (R.<em>something</em> file.)
 */
@SystemService(Context.LAYOUT_INFLATER_SERVICE)
public abstract class LayoutInflater {

    private static final String TAG = LayoutInflater.class.getSimpleName();
    private static final boolean DEBUG = false;

    
Empty stack trace used to avoid log spam in re-throw exceptions. /** Empty stack trace used to avoid log spam in re-throw exceptions. */
    private static final StackTraceElement[] EMPTY_STACK_TRACE = new StackTraceElement[0];

    
This field should be made private, so it is hidden from the SDK.
{@hide}
/**
     * This field should be made private, so it is hidden from the SDK.
     * {@hide}
     */
    protected final Context mContext;

    // these are optional, set by the caller
    private boolean mFactorySet;
    private Factory mFactory;
    private Factory2 mFactory2;
    private Factory2 mPrivateFactory;
    private Filter mFilter;

    final Object[] mConstructorArgs = new Object[2];

    static final Class<?>[] mConstructorSignature = new Class[] {
            Context.class, AttributeSet.class};

    private static final HashMap<String, Constructor<? extends View>> sConstructorMap =
            new HashMap<String, Constructor<? extends View>>();

    private HashMap<String, Boolean> mFilterMap;

    private TypedValue mTempValue;

    private static final String TAG_MERGE = "merge";
    private static final String TAG_INCLUDE = "include";
    private static final String TAG_1995 = "blink";
    private static final String TAG_REQUEST_FOCUS = "requestFocus";
    private static final String TAG_TAG = "tag";

    private static final String ATTR_LAYOUT = "layout";

    private static final int[] ATTRS_THEME = new int[] {
            com.android.internal.R.attr.theme };

    
Hook to allow clients of the LayoutInflater to restrict the set of Views that are allowed
to be inflated.
/**
     * Hook to allow clients of the LayoutInflater to restrict the set of Views that are allowed
     * to be inflated.
     *
     */
    public interface Filter {
        
Hook to allow clients of the LayoutInflater to restrict the set of Views
that are allowed to be inflated.
Params:
clazz – The class object for the View that is about to be inflated
Returns:
True if this class is allowed to be inflated, or false otherwise/**
         * Hook to allow clients of the LayoutInflater to restrict the set of Views
         * that are allowed to be inflated.
         *
         * @param clazz The class object for the View that is about to be inflated
         *
         * @return True if this class is allowed to be inflated, or false otherwise
         */
        @SuppressWarnings("unchecked")
        boolean onLoadClass(Class clazz);
    }

    public interface Factory {
        
Hook you can supply that is called when inflating from a LayoutInflater.
You can use this to customize the tag names available in your XML
layout files.

Note that it is good practice to prefix these custom names with your
package (i.e., com.coolcompany.apps) to avoid conflicts with system
names.
Params:
name – Tag name to be inflated.
context – The context the view is being created in.
attrs – Inflation attributes as specified in XML file.
Returns:
View Newly created view. Return null for the default
        behavior./**
         * Hook you can supply that is called when inflating from a LayoutInflater.
         * You can use this to customize the tag names available in your XML
         * layout files.
         *
         * <p>
         * Note that it is good practice to prefix these custom names with your
         * package (i.e., com.coolcompany.apps) to avoid conflicts with system
         * names.
         *
         * @param name Tag name to be inflated.
         * @param context The context the view is being created in.
         * @param attrs Inflation attributes as specified in XML file.
         *
         * @return View Newly created view. Return null for the default
         *         behavior.
         */
        public View onCreateView(String name, Context context, AttributeSet attrs);
    }

    public interface Factory2 extends Factory {
        
Version of Factory.onCreateView(String, Context, AttributeSet) that also supplies the parent that the view created view will be placed in. 
Params:
parent – The parent that the created view will be placed
in; note that this may be null.
name – Tag name to be inflated.
context – The context the view is being created in.
attrs – Inflation attributes as specified in XML file.
Returns:
View Newly created view. Return null for the default
        behavior./**
         * Version of {@link #onCreateView(String, Context, AttributeSet)}
         * that also supplies the parent that the view created view will be
         * placed in.
         *
         * @param parent The parent that the created view will be placed
         * in; <em>note that this may be null</em>.
         * @param name Tag name to be inflated.
         * @param context The context the view is being created in.
         * @param attrs Inflation attributes as specified in XML file.
         *
         * @return View Newly created view. Return null for the default
         *         behavior.
         */
        public View onCreateView(View parent, String name, Context context, AttributeSet attrs);
    }

    private static class FactoryMerger implements Factory2 {
        private final Factory mF1, mF2;
        private final Factory2 mF12, mF22;

        FactoryMerger(Factory f1, Factory2 f12, Factory f2, Factory2 f22) {
            mF1 = f1;
            mF2 = f2;
            mF12 = f12;
            mF22 = f22;
        }

        public View onCreateView(String name, Context context, AttributeSet attrs) {
            View v = mF1.onCreateView(name, context, attrs);
            if (v != null) return v;
            return mF2.onCreateView(name, context, attrs);
        }

        public View onCreateView(View parent, String name, Context context, AttributeSet attrs) {
            View v = mF12 != null ? mF12.onCreateView(parent, name, context, attrs)
                    : mF1.onCreateView(name, context, attrs);
            if (v != null) return v;
            return mF22 != null ? mF22.onCreateView(parent, name, context, attrs)
                    : mF2.onCreateView(name, context, attrs);
        }
    }

    
Create a new LayoutInflater instance associated with a particular Context. Applications will almost always want to use Context.getSystemService() to retrieve the standard Context.INFLATER_SERVICE. 
Params:
context – The Context in which this LayoutInflater will create its
Views; most importantly, this supplies the theme from which the default
values for their attributes are retrieved./**
     * Create a new LayoutInflater instance associated with a particular Context.
     * Applications will almost always want to use
     * {@link Context#getSystemService Context.getSystemService()} to retrieve
     * the standard {@link Context#LAYOUT_INFLATER_SERVICE Context.INFLATER_SERVICE}.
     *
     * @param context The Context in which this LayoutInflater will create its
     * Views; most importantly, this supplies the theme from which the default
     * values for their attributes are retrieved.
     */
    protected LayoutInflater(Context context) {
        mContext = context;
    }

    
Create a new LayoutInflater instance that is a copy of an existing LayoutInflater, optionally with its Context changed. For use in implementing cloneInContext. 
Params:
original – The original LayoutInflater to copy.
newContext – The new Context to use./**
     * Create a new LayoutInflater instance that is a copy of an existing
     * LayoutInflater, optionally with its Context changed.  For use in
     * implementing {@link #cloneInContext}.
     *
     * @param original The original LayoutInflater to copy.
     * @param newContext The new Context to use.
     */
    protected LayoutInflater(LayoutInflater original, Context newContext) {
        mContext = newContext;
        mFactory = original.mFactory;
        mFactory2 = original.mFactory2;
        mPrivateFactory = original.mPrivateFactory;
        setFilter(original.mFilter);
    }

    
Obtains the LayoutInflater from the given context.
/**
     * Obtains the LayoutInflater from the given context.
     */
    public static LayoutInflater from(Context context) {
        LayoutInflater LayoutInflater =
                (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        if (LayoutInflater == null) {
            throw new AssertionError("LayoutInflater not found.");
        }
        return LayoutInflater;
    }

    
Create a copy of the existing LayoutInflater object, with the copy pointing to a different Context than the original. This is used by ContextThemeWrapper to create a new LayoutInflater to go along with the new Context theme. 
Params:
newContext – The new Context to associate with the new LayoutInflater.
May be the same as the original Context if desired.
Returns:
Returns a brand spanking new LayoutInflater object associated with
the given Context./**
     * Create a copy of the existing LayoutInflater object, with the copy
     * pointing to a different Context than the original.  This is used by
     * {@link ContextThemeWrapper} to create a new LayoutInflater to go along
     * with the new Context theme.
     *
     * @param newContext The new Context to associate with the new LayoutInflater.
     * May be the same as the original Context if desired.
     *
     * @return Returns a brand spanking new LayoutInflater object associated with
     * the given Context.
     */
    public abstract LayoutInflater cloneInContext(Context newContext);

    
Return the context we are running in, for access to resources, class
loader, etc.
/**
     * Return the context we are running in, for access to resources, class
     * loader, etc.
     */
    public Context getContext() {
        return mContext;
    }

    
Return the current Factory (or null). This is called on each element name. If the factory returns a View, add that to the hierarchy. If it returns null, proceed to call onCreateView(name). /**
     * Return the current {@link Factory} (or null). This is called on each element
     * name. If the factory returns a View, add that to the hierarchy. If it
     * returns null, proceed to call onCreateView(name).
     */
    public final Factory getFactory() {
        return mFactory;
    }

    
Return the current Factory2. Returns null if no factory is set or the set factory does not implement the Factory2 interface. This is called on each element name. If the factory returns a View, add that to the hierarchy. If it returns null, proceed to call onCreateView(name). /**
     * Return the current {@link Factory2}.  Returns null if no factory is set
     * or the set factory does not implement the {@link Factory2} interface.
     * This is called on each element
     * name. If the factory returns a View, add that to the hierarchy. If it
     * returns null, proceed to call onCreateView(name).
     */
    public final Factory2 getFactory2() {
        return mFactory2;
    }

    
Attach a custom Factory interface for creating views while using this LayoutInflater. This must not be null, and can only be set once; after setting, you can not change the factory. This is called on each element name as the xml is parsed. If the factory returns a View, that is added to the hierarchy. If it returns null, the next factory default onCreateView method is called. 
If you have an existing LayoutInflater and want to add your own factory to it, use cloneInContext to clone the existing instance and then you can use this function (once) on the returned new instance. This will merge your own factory with whatever factory the original instance is using. /**
     * Attach a custom Factory interface for creating views while using
     * this LayoutInflater.  This must not be null, and can only be set once;
     * after setting, you can not change the factory.  This is
     * called on each element name as the xml is parsed. If the factory returns
     * a View, that is added to the hierarchy. If it returns null, the next
     * factory default {@link #onCreateView} method is called.
     *
     * <p>If you have an existing
     * LayoutInflater and want to add your own factory to it, use
     * {@link #cloneInContext} to clone the existing instance and then you
     * can use this function (once) on the returned new instance.  This will
     * merge your own factory with whatever factory the original instance is
     * using.
     */
    public void setFactory(Factory factory) {
        if (mFactorySet) {
            throw new IllegalStateException("A factory has already been set on this LayoutInflater");
        }
        if (factory == null) {
            throw new NullPointerException("Given factory can not be null");
        }
        mFactorySet = true;
        if (mFactory == null) {
            mFactory = factory;
        } else {
            mFactory = new FactoryMerger(factory, null, mFactory, mFactory2);
        }
    }

    
Like setFactory, but allows you to set a Factory2 interface. /**
     * Like {@link #setFactory}, but allows you to set a {@link Factory2}
     * interface.
     */
    public void setFactory2(Factory2 factory) {
        if (mFactorySet) {
            throw new IllegalStateException("A factory has already been set on this LayoutInflater");
        }
        if (factory == null) {
            throw new NullPointerException("Given factory can not be null");
        }
        mFactorySet = true;
        if (mFactory == null) {
            mFactory = mFactory2 = factory;
        } else {
            mFactory = mFactory2 = new FactoryMerger(factory, factory, mFactory, mFactory2);
        }
    }

    
@hide
for use by framework/**
     * @hide for use by framework
     */
    public void setPrivateFactory(Factory2 factory) {
        if (mPrivateFactory == null) {
            mPrivateFactory = factory;
        } else {
            mPrivateFactory = new FactoryMerger(factory, factory, mPrivateFactory, mPrivateFactory);
        }
    }

    
Returns:
The Filter currently used by this LayoutInflater to restrict the set of Views that are allowed to be inflated./**
     * @return The {@link Filter} currently used by this LayoutInflater to restrict the set of Views
     * that are allowed to be inflated.
     */
    public Filter getFilter() {
        return mFilter;
    }

    
Sets the Filter to by this LayoutInflater. If a view is attempted to be inflated which is not allowed by the Filter, the inflate(int, ViewGroup) call will throw an InflateException. This filter will replace any previous filter set on this LayoutInflater. 
Params:
filter – The Filter which restricts the set of Views that are allowed to be inflated.
       This filter will replace any previous filter set on this LayoutInflater./**
     * Sets the {@link Filter} to by this LayoutInflater. If a view is attempted to be inflated
     * which is not allowed by the {@link Filter}, the {@link #inflate(int, ViewGroup)} call will
     * throw an {@link InflateException}. This filter will replace any previous filter set on this
     * LayoutInflater.
     *
     * @param filter The Filter which restricts the set of Views that are allowed to be inflated.
     *        This filter will replace any previous filter set on this LayoutInflater.
     */
    public void setFilter(Filter filter) {
        mFilter = filter;
        if (filter != null) {
            mFilterMap = new HashMap<String, Boolean>();
        }
    }

    
Inflate a new view hierarchy from the specified xml resource. Throws InflateException if there is an error. 
Params:
resource – ID for an XML layout resource to load (e.g.,
       R.layout.main_page)
root – Optional view to be the parent of the generated hierarchy.
Returns:
The root View of the inflated hierarchy. If root was supplied,
        this is the root View; otherwise it is the root of the inflated
        XML file./**
     * Inflate a new view hierarchy from the specified xml resource. Throws
     * {@link InflateException} if there is an error.
     *
     * @param resource ID for an XML layout resource to load (e.g.,
     *        <code>R.layout.main_page</code>)
     * @param root Optional view to be the parent of the generated hierarchy.
     * @return The root View of the inflated hierarchy. If root was supplied,
     *         this is the root View; otherwise it is the root of the inflated
     *         XML file.
     */
    public View inflate(@LayoutRes int resource, @Nullable ViewGroup root) {
        return inflate(resource, root, root != null);
    }

    
Inflate a new view hierarchy from the specified xml node. Throws InflateException if there is an error. * 

Important   For performance
reasons, view inflation relies heavily on pre-processing of XML files
that is done at build time. Therefore, it is not currently possible to
use LayoutInflater with an XmlPullParser over a plain XML file at runtime.
Params:
parser – XML dom node containing the description of the view
       hierarchy.
root – Optional view to be the parent of the generated hierarchy.
Returns:
The root View of the inflated hierarchy. If root was supplied,
        this is the root View; otherwise it is the root of the inflated
        XML file./**
     * Inflate a new view hierarchy from the specified xml node. Throws
     * {@link InflateException} if there is an error. *
     * <p>
     * <em><strong>Important</strong></em>&nbsp;&nbsp;&nbsp;For performance
     * reasons, view inflation relies heavily on pre-processing of XML files
     * that is done at build time. Therefore, it is not currently possible to
     * use LayoutInflater with an XmlPullParser over a plain XML file at runtime.
     *
     * @param parser XML dom node containing the description of the view
     *        hierarchy.
     * @param root Optional view to be the parent of the generated hierarchy.
     * @return The root View of the inflated hierarchy. If root was supplied,
     *         this is the root View; otherwise it is the root of the inflated
     *         XML file.
     */
    public View inflate(XmlPullParser parser, @Nullable ViewGroup root) {
        return inflate(parser, root, root != null);
    }

    
Inflate a new view hierarchy from the specified xml resource. Throws InflateException if there is an error. 
Params:
resource – ID for an XML layout resource to load (e.g.,
       R.layout.main_page)
root – Optional view to be the parent of the generated hierarchy (if
       attachToRoot is true), or else simply an object that
       provides a set of LayoutParams values for root of the returned
       hierarchy (if attachToRoot is false.)
attachToRoot – Whether the inflated hierarchy should be attached to
       the root parameter? If false, root is only used to create the
       correct subclass of LayoutParams for the root view in the XML.
Returns:
The root View of the inflated hierarchy. If root was supplied and
        attachToRoot is true, this is root; otherwise it is the root of
        the inflated XML file./**
     * Inflate a new view hierarchy from the specified xml resource. Throws
     * {@link InflateException} if there is an error.
     *
     * @param resource ID for an XML layout resource to load (e.g.,
     *        <code>R.layout.main_page</code>)
     * @param root Optional view to be the parent of the generated hierarchy (if
     *        <em>attachToRoot</em> is true), or else simply an object that
     *        provides a set of LayoutParams values for root of the returned
     *        hierarchy (if <em>attachToRoot</em> is false.)
     * @param attachToRoot Whether the inflated hierarchy should be attached to
     *        the root parameter? If false, root is only used to create the
     *        correct subclass of LayoutParams for the root view in the XML.
     * @return The root View of the inflated hierarchy. If root was supplied and
     *         attachToRoot is true, this is root; otherwise it is the root of
     *         the inflated XML file.
     */
    public View inflate(@LayoutRes int resource, @Nullable ViewGroup root, boolean attachToRoot) {
        final Resources res = getContext().getResources();
        if (DEBUG) {
            Log.d(TAG, "INFLATING from resource: \"" + res.getResourceName(resource) + "\" ("
                    + Integer.toHexString(resource) + ")");
        }

        final XmlResourceParser parser = res.getLayout(resource);
        try {
            return inflate(parser, root, attachToRoot);
        } finally {
            parser.close();
        }
    }

    
Inflate a new view hierarchy from the specified XML node. Throws InflateException if there is an error. 

Important   For performance
reasons, view inflation relies heavily on pre-processing of XML files
that is done at build time. Therefore, it is not currently possible to
use LayoutInflater with an XmlPullParser over a plain XML file at runtime.
Params:
parser – XML dom node containing the description of the view
       hierarchy.
root – Optional view to be the parent of the generated hierarchy (if
       attachToRoot is true), or else simply an object that
       provides a set of LayoutParams values for root of the returned
       hierarchy (if attachToRoot is false.)
attachToRoot – Whether the inflated hierarchy should be attached to
       the root parameter? If false, root is only used to create the
       correct subclass of LayoutParams for the root view in the XML.
Returns:
The root View of the inflated hierarchy. If root was supplied and
        attachToRoot is true, this is root; otherwise it is the root of
        the inflated XML file./**
     * Inflate a new view hierarchy from the specified XML node. Throws
     * {@link InflateException} if there is an error.
     * <p>
     * <em><strong>Important</strong></em>&nbsp;&nbsp;&nbsp;For performance
     * reasons, view inflation relies heavily on pre-processing of XML files
     * that is done at build time. Therefore, it is not currently possible to
     * use LayoutInflater with an XmlPullParser over a plain XML file at runtime.
     *
     * @param parser XML dom node containing the description of the view
     *        hierarchy.
     * @param root Optional view to be the parent of the generated hierarchy (if
     *        <em>attachToRoot</em> is true), or else simply an object that
     *        provides a set of LayoutParams values for root of the returned
     *        hierarchy (if <em>attachToRoot</em> is false.)
     * @param attachToRoot Whether the inflated hierarchy should be attached to
     *        the root parameter? If false, root is only used to create the
     *        correct subclass of LayoutParams for the root view in the XML.
     * @return The root View of the inflated hierarchy. If root was supplied and
     *         attachToRoot is true, this is root; otherwise it is the root of
     *         the inflated XML file.
     */
    public View inflate(XmlPullParser parser, @Nullable ViewGroup root, boolean attachToRoot) {
        synchronized (mConstructorArgs) {
            Trace.traceBegin(Trace.TRACE_TAG_VIEW, "inflate");

            final Context inflaterContext = mContext;
            final AttributeSet attrs = Xml.asAttributeSet(parser);
            Context lastContext = (Context) mConstructorArgs[0];
            mConstructorArgs[0] = inflaterContext;
            View result = root;

            try {
                // Look for the root node.
                int type;
                while ((type = parser.next()) != XmlPullParser.START_TAG &&
                        type != XmlPullParser.END_DOCUMENT) {
                    // Empty
                }

                if (type != XmlPullParser.START_TAG) {
                    throw new InflateException(parser.getPositionDescription()
                            + ": No start tag found!");
                }

                final String name = parser.getName();

                if (DEBUG) {
                    System.out.println("**************************");
                    System.out.println("Creating root view: "
                            + name);
                    System.out.println("**************************");
                }

                if (TAG_MERGE.equals(name)) {
                    if (root == null || !attachToRoot) {
                        throw new InflateException("<merge /> can be used only with a valid "
                                + "ViewGroup root and attachToRoot=true");
                    }

                    rInflate(parser, root, inflaterContext, attrs, false);
                } else {
                    // Temp is the root view that was found in the xml
                    final View temp = createViewFromTag(root, name, inflaterContext, attrs);

                    ViewGroup.LayoutParams params = null;

                    if (root != null) {
                        if (DEBUG) {
                            System.out.println("Creating params from root: " +
                                    root);
                        }
                        // Create layout params that match root, if supplied
                        params = root.generateLayoutParams(attrs);
                        if (!attachToRoot) {
                            // Set the layout params for temp if we are not
                            // attaching. (If we are, we use addView, below)
                            temp.setLayoutParams(params);
                        }
                    }

                    if (DEBUG) {
                        System.out.println("-----> start inflating children");
                    }

                    // Inflate all children under temp against its context.
                    rInflateChildren(parser, temp, attrs, true);

                    if (DEBUG) {
                        System.out.println("-----> done inflating children");
                    }

                    // We are supposed to attach all the views we found (int temp)
                    // to root. Do that now.
                    if (root != null && attachToRoot) {
                        root.addView(temp, params);
                    }

                    // Decide whether to return the root that was passed in or the
                    // top view found in xml.
                    if (root == null || !attachToRoot) {
                        result = temp;
                    }
                }

            } catch (XmlPullParserException e) {
                final InflateException ie = new InflateException(e.getMessage(), e);
                ie.setStackTrace(EMPTY_STACK_TRACE);
                throw ie;
            } catch (Exception e) {
                final InflateException ie = new InflateException(parser.getPositionDescription()
                        + ": " + e.getMessage(), e);
                ie.setStackTrace(EMPTY_STACK_TRACE);
                throw ie;
            } finally {
                // Don't retain static reference on context.
                mConstructorArgs[0] = lastContext;
                mConstructorArgs[1] = null;

                Trace.traceEnd(Trace.TRACE_TAG_VIEW);
            }

            return result;
        }
    }

    private static final ClassLoader BOOT_CLASS_LOADER = LayoutInflater.class.getClassLoader();

    private final boolean verifyClassLoader(Constructor<? extends View> constructor) {
        final ClassLoader constructorLoader = constructor.getDeclaringClass().getClassLoader();
        if (constructorLoader == BOOT_CLASS_LOADER) {
            // fast path for boot class loader (most common case?) - always ok
            return true;
        }
        // in all normal cases (no dynamic code loading), we will exit the following loop on the
        // first iteration (i.e. when the declaring classloader is the contexts class loader).
        ClassLoader cl = mContext.getClassLoader();
        do {
            if (constructorLoader == cl) {
                return true;
            }
            cl = cl.getParent();
        } while (cl != null);
        return false;
    }

    
Low-level function for instantiating a view by name. This attempts to
instantiate a view class of the given name found in this
LayoutInflater's ClassLoader.

There are two things that can happen in an error case: either the
exception describing the error will be thrown, or a null will be
returned. You must deal with both possibilities -- the former will happen
the first time createView() is called for a class of a particular name,
the latter every time there-after for that class name.
Params:
name – The full name of the class to be instantiated.
attrs – The XML attributes supplied for this instance.
Returns:
View The newly instantiated view, or null./**
     * Low-level function for instantiating a view by name. This attempts to
     * instantiate a view class of the given <var>name</var> found in this
     * LayoutInflater's ClassLoader.
     *
     * <p>
     * There are two things that can happen in an error case: either the
     * exception describing the error will be thrown, or a null will be
     * returned. You must deal with both possibilities -- the former will happen
     * the first time createView() is called for a class of a particular name,
     * the latter every time there-after for that class name.
     *
     * @param name The full name of the class to be instantiated.
     * @param attrs The XML attributes supplied for this instance.
     *
     * @return View The newly instantiated view, or null.
     */
    public final View createView(String name, String prefix, AttributeSet attrs)
            throws ClassNotFoundException, InflateException {
        Constructor<? extends View> constructor = sConstructorMap.get(name);
        if (constructor != null && !verifyClassLoader(constructor)) {
            constructor = null;
            sConstructorMap.remove(name);
        }
        Class<? extends View> clazz = null;

        try {
            Trace.traceBegin(Trace.TRACE_TAG_VIEW, name);

            if (constructor == null) {
                // Class not found in the cache, see if it's real, and try to add it
                clazz = mContext.getClassLoader().loadClass(
                        prefix != null ? (prefix + name) : name).asSubclass(View.class);

                if (mFilter != null && clazz != null) {
                    boolean allowed = mFilter.onLoadClass(clazz);
                    if (!allowed) {
                        failNotAllowed(name, prefix, attrs);
                    }
                }
                constructor = clazz.getConstructor(mConstructorSignature);
                constructor.setAccessible(true);
                sConstructorMap.put(name, constructor);
            } else {
                // If we have a filter, apply it to cached constructor
                if (mFilter != null) {
                    // Have we seen this name before?
                    Boolean allowedState = mFilterMap.get(name);
                    if (allowedState == null) {
                        // New class -- remember whether it is allowed
                        clazz = mContext.getClassLoader().loadClass(
                                prefix != null ? (prefix + name) : name).asSubclass(View.class);

                        boolean allowed = clazz != null && mFilter.onLoadClass(clazz);
                        mFilterMap.put(name, allowed);
                        if (!allowed) {
                            failNotAllowed(name, prefix, attrs);
                        }
                    } else if (allowedState.equals(Boolean.FALSE)) {
                        failNotAllowed(name, prefix, attrs);
                    }
                }
            }

            Object lastContext = mConstructorArgs[0];
            if (mConstructorArgs[0] == null) {
                // Fill in the context if not already within inflation.
                mConstructorArgs[0] = mContext;
            }
            Object[] args = mConstructorArgs;
            args[1] = attrs;

            final View view = constructor.newInstance(args);
            if (view instanceof ViewStub) {
                // Use the same context when inflating ViewStub later.
                final ViewStub viewStub = (ViewStub) view;
                viewStub.setLayoutInflater(cloneInContext((Context) args[0]));
            }
            mConstructorArgs[0] = lastContext;
            return view;

        } catch (NoSuchMethodException e) {
            final InflateException ie = new InflateException(attrs.getPositionDescription()
                    + ": Error inflating class " + (prefix != null ? (prefix + name) : name), e);
            ie.setStackTrace(EMPTY_STACK_TRACE);
            throw ie;

        } catch (ClassCastException e) {
            // If loaded class is not a View subclass
            final InflateException ie = new InflateException(attrs.getPositionDescription()
                    + ": Class is not a View " + (prefix != null ? (prefix + name) : name), e);
            ie.setStackTrace(EMPTY_STACK_TRACE);
            throw ie;
        } catch (ClassNotFoundException e) {
            // If loadClass fails, we should propagate the exception.
            throw e;
        } catch (Exception e) {
            final InflateException ie = new InflateException(
                    attrs.getPositionDescription() + ": Error inflating class "
                            + (clazz == null ? "<unknown>" : clazz.getName()), e);
            ie.setStackTrace(EMPTY_STACK_TRACE);
            throw ie;
        } finally {
            Trace.traceEnd(Trace.TRACE_TAG_VIEW);
        }
    }

    
Throw an exception because the specified class is not allowed to be inflated.
/**
     * Throw an exception because the specified class is not allowed to be inflated.
     */
    private void failNotAllowed(String name, String prefix, AttributeSet attrs) {
        throw new InflateException(attrs.getPositionDescription()
                + ": Class not allowed to be inflated "+ (prefix != null ? (prefix + name) : name));
    }

    
This routine is responsible for creating the correct subclass of View
given the xml element name. Override it to handle custom view objects. If
you override this in your subclass be sure to call through to
super.onCreateView(name) for names you do not recognize.
Params:
name – The fully qualified class name of the View to be create.
attrs – An AttributeSet of attributes to apply to the View.
Returns:
View The View created./**
     * This routine is responsible for creating the correct subclass of View
     * given the xml element name. Override it to handle custom view objects. If
     * you override this in your subclass be sure to call through to
     * super.onCreateView(name) for names you do not recognize.
     *
     * @param name The fully qualified class name of the View to be create.
     * @param attrs An AttributeSet of attributes to apply to the View.
     *
     * @return View The View created.
     */
    protected View onCreateView(String name, AttributeSet attrs)
            throws ClassNotFoundException {
        return createView(name, "android.view.", attrs);
    }

    
Version of onCreateView(String, AttributeSet) that also takes the future parent of the view being constructed. The default implementation simply calls onCreateView(String, AttributeSet). 
Params:
parent – The future parent of the returned view.  Note that
this may be null.
name – The fully qualified class name of the View to be create.
attrs – An AttributeSet of attributes to apply to the View.
Returns:
View The View created./**
     * Version of {@link #onCreateView(String, AttributeSet)} that also
     * takes the future parent of the view being constructed.  The default
     * implementation simply calls {@link #onCreateView(String, AttributeSet)}.
     *
     * @param parent The future parent of the returned view.  <em>Note that
     * this may be null.</em>
     * @param name The fully qualified class name of the View to be create.
     * @param attrs An AttributeSet of attributes to apply to the View.
     *
     * @return View The View created.
     */
    protected View onCreateView(View parent, String name, AttributeSet attrs)
            throws ClassNotFoundException {
        return onCreateView(name, attrs);
    }

    
Convenience method for calling through to the five-arg createViewFromTag method. This method passes false for the ignoreThemeAttr argument and should be used for everything except &gt;include> tag parsing. /**
     * Convenience method for calling through to the five-arg createViewFromTag
     * method. This method passes {@code false} for the {@code ignoreThemeAttr}
     * argument and should be used for everything except {@code &gt;include>}
     * tag parsing.
     */
    private View createViewFromTag(View parent, String name, Context context, AttributeSet attrs) {
        return createViewFromTag(parent, name, context, attrs, false);
    }

    
Creates a view from a tag name using the supplied attribute set.

Note: Default visibility so the BridgeInflater can
override it.
Params:
parent – the parent view, used to inflate layout params
name – the name of the XML tag used to define the view
context – the inflation context for the view, typically the parent or base layout inflater context
attrs – the attribute set for the XML tag used to define the view
ignoreThemeAttr – true to ignore the android:theme attribute (if set) for the view being inflated, false otherwise/**
     * Creates a view from a tag name using the supplied attribute set.
     * <p>
     * <strong>Note:</strong> Default visibility so the BridgeInflater can
     * override it.
     *
     * @param parent the parent view, used to inflate layout params
     * @param name the name of the XML tag used to define the view
     * @param context the inflation context for the view, typically the
     *                {@code parent} or base layout inflater context
     * @param attrs the attribute set for the XML tag used to define the view
     * @param ignoreThemeAttr {@code true} to ignore the {@code android:theme}
     *                        attribute (if set) for the view being inflated,
     *                        {@code false} otherwise
     */
    View createViewFromTag(View parent, String name, Context context, AttributeSet attrs,
            boolean ignoreThemeAttr) {
        if (name.equals("view")) {
            name = attrs.getAttributeValue(null, "class");
        }

        // Apply a theme wrapper, if allowed and one is specified.
        if (!ignoreThemeAttr) {
            final TypedArray ta = context.obtainStyledAttributes(attrs, ATTRS_THEME);
            final int themeResId = ta.getResourceId(0, 0);
            if (themeResId != 0) {
                context = new ContextThemeWrapper(context, themeResId);
            }
            ta.recycle();
        }

        if (name.equals(TAG_1995)) {
            // Let's party like it's 1995!
            return new BlinkLayout(context, attrs);
        }

        try {
            View view;
            if (mFactory2 != null) {
                view = mFactory2.onCreateView(parent, name, context, attrs);
            } else if (mFactory != null) {
                view = mFactory.onCreateView(name, context, attrs);
            } else {
                view = null;
            }

            if (view == null && mPrivateFactory != null) {
                view = mPrivateFactory.onCreateView(parent, name, context, attrs);
            }

            if (view == null) {
                final Object lastContext = mConstructorArgs[0];
                mConstructorArgs[0] = context;
                try {
                    if (-1 == name.indexOf('.')) {
                        view = onCreateView(parent, name, attrs);
                    } else {
                        view = createView(name, null, attrs);
                    }
                } finally {
                    mConstructorArgs[0] = lastContext;
                }
            }

            return view;
        } catch (InflateException e) {
            throw e;

        } catch (ClassNotFoundException e) {
            final InflateException ie = new InflateException(attrs.getPositionDescription()
                    + ": Error inflating class " + name, e);
            ie.setStackTrace(EMPTY_STACK_TRACE);
            throw ie;

        } catch (Exception e) {
            final InflateException ie = new InflateException(attrs.getPositionDescription()
                    + ": Error inflating class " + name, e);
            ie.setStackTrace(EMPTY_STACK_TRACE);
            throw ie;
        }
    }

    
Recursive method used to inflate internal (non-root) children. This method calls through to rInflate using the parent context as the inflation context. Note: Default visibility so the BridgeInflater can
call it.
/**
     * Recursive method used to inflate internal (non-root) children. This
     * method calls through to {@link #rInflate} using the parent context as
     * the inflation context.
     * <strong>Note:</strong> Default visibility so the BridgeInflater can
     * call it.
     */
    final void rInflateChildren(XmlPullParser parser, View parent, AttributeSet attrs,
            boolean finishInflate) throws XmlPullParserException, IOException {
        rInflate(parser, parent, parent.getContext(), attrs, finishInflate);
    }

    
Recursive method used to descend down the xml hierarchy and instantiate
views, instantiate their children, and then call onFinishInflate().

Note: Default visibility so the BridgeInflater can
override it.
/**
     * Recursive method used to descend down the xml hierarchy and instantiate
     * views, instantiate their children, and then call onFinishInflate().
     * <p>
     * <strong>Note:</strong> Default visibility so the BridgeInflater can
     * override it.
     */
    void rInflate(XmlPullParser parser, View parent, Context context,
            AttributeSet attrs, boolean finishInflate) throws XmlPullParserException, IOException {

        final int depth = parser.getDepth();
        int type;
        boolean pendingRequestFocus = false;

        while (((type = parser.next()) != XmlPullParser.END_TAG ||
                parser.getDepth() > depth) && type != XmlPullParser.END_DOCUMENT) {

            if (type != XmlPullParser.START_TAG) {
                continue;
            }

            final String name = parser.getName();

            if (TAG_REQUEST_FOCUS.equals(name)) {
                pendingRequestFocus = true;
                consumeChildElements(parser);
            } else if (TAG_TAG.equals(name)) {
                parseViewTag(parser, parent, attrs);
            } else if (TAG_INCLUDE.equals(name)) {
                if (parser.getDepth() == 0) {
                    throw new InflateException("<include /> cannot be the root element");
                }
                parseInclude(parser, context, parent, attrs);
            } else if (TAG_MERGE.equals(name)) {
                throw new InflateException("<merge /> must be the root element");
            } else {
                final View view = createViewFromTag(parent, name, context, attrs);
                final ViewGroup viewGroup = (ViewGroup) parent;
                final ViewGroup.LayoutParams params = viewGroup.generateLayoutParams(attrs);
                rInflateChildren(parser, view, attrs, true);
                viewGroup.addView(view, params);
            }
        }

        if (pendingRequestFocus) {
            parent.restoreDefaultFocus();
        }

        if (finishInflate) {
            parent.onFinishInflate();
        }
    }

    
Parses a <tag> element and sets a keyed tag on the
containing View.
/**
     * Parses a <code>&lt;tag&gt;</code> element and sets a keyed tag on the
     * containing View.
     */
    private void parseViewTag(XmlPullParser parser, View view, AttributeSet attrs)
            throws XmlPullParserException, IOException {
        final Context context = view.getContext();
        final TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.ViewTag);
        final int key = ta.getResourceId(R.styleable.ViewTag_id, 0);
        final CharSequence value = ta.getText(R.styleable.ViewTag_value);
        view.setTag(key, value);
        ta.recycle();

        consumeChildElements(parser);
    }

    private void parseInclude(XmlPullParser parser, Context context, View parent,
            AttributeSet attrs) throws XmlPullParserException, IOException {
        int type;

        if (parent instanceof ViewGroup) {
            // Apply a theme wrapper, if requested. This is sort of a weird
            // edge case, since developers think the <include> overwrites
            // values in the AttributeSet of the included View. So, if the
            // included View has a theme attribute, we'll need to ignore it.
            final TypedArray ta = context.obtainStyledAttributes(attrs, ATTRS_THEME);
            final int themeResId = ta.getResourceId(0, 0);
            final boolean hasThemeOverride = themeResId != 0;
            if (hasThemeOverride) {
                context = new ContextThemeWrapper(context, themeResId);
            }
            ta.recycle();

            // If the layout is pointing to a theme attribute, we have to
            // massage the value to get a resource identifier out of it.
            int layout = attrs.getAttributeResourceValue(null, ATTR_LAYOUT, 0);
            if (layout == 0) {
                final String value = attrs.getAttributeValue(null, ATTR_LAYOUT);
                if (value == null || value.length() <= 0) {
                    throw new InflateException("You must specify a layout in the"
                            + " include tag: <include layout=\"@layout/layoutID\" />");
                }

                // Attempt to resolve the "?attr/name" string to an attribute
                // within the default (e.g. application) package.
                layout = context.getResources().getIdentifier(
                        value.substring(1), "attr", context.getPackageName());

            }

            // The layout might be referencing a theme attribute.
            if (mTempValue == null) {
                mTempValue = new TypedValue();
            }
            if (layout != 0 && context.getTheme().resolveAttribute(layout, mTempValue, true)) {
                layout = mTempValue.resourceId;
            }

            if (layout == 0) {
                final String value = attrs.getAttributeValue(null, ATTR_LAYOUT);
                throw new InflateException("You must specify a valid layout "
                        + "reference. The layout ID " + value + " is not valid.");
            } else {
                final XmlResourceParser childParser = context.getResources().getLayout(layout);

                try {
                    final AttributeSet childAttrs = Xml.asAttributeSet(childParser);

                    while ((type = childParser.next()) != XmlPullParser.START_TAG &&
                            type != XmlPullParser.END_DOCUMENT) {
                        // Empty.
                    }

                    if (type != XmlPullParser.START_TAG) {
                        throw new InflateException(childParser.getPositionDescription() +
                                ": No start tag found!");
                    }

                    final String childName = childParser.getName();

                    if (TAG_MERGE.equals(childName)) {
                        // The <merge> tag doesn't support android:theme, so
                        // nothing special to do here.
                        rInflate(childParser, parent, context, childAttrs, false);
                    } else {
                        final View view = createViewFromTag(parent, childName,
                                context, childAttrs, hasThemeOverride);
                        final ViewGroup group = (ViewGroup) parent;

                        final TypedArray a = context.obtainStyledAttributes(
                                attrs, R.styleable.Include);
                        final int id = a.getResourceId(R.styleable.Include_id, View.NO_ID);
                        final int visibility = a.getInt(R.styleable.Include_visibility, -1);
                        a.recycle();

                        // We try to load the layout params set in the <include /> tag.
                        // If the parent can't generate layout params (ex. missing width
                        // or height for the framework ViewGroups, though this is not
                        // necessarily true of all ViewGroups) then we expect it to throw
                        // a runtime exception.
                        // We catch this exception and set localParams accordingly: true
                        // means we successfully loaded layout params from the <include>
                        // tag, false means we need to rely on the included layout params.
                        ViewGroup.LayoutParams params = null;
                        try {
                            params = group.generateLayoutParams(attrs);
                        } catch (RuntimeException e) {
                            // Ignore, just fail over to child attrs.
                        }
                        if (params == null) {
                            params = group.generateLayoutParams(childAttrs);
                        }
                        view.setLayoutParams(params);

                        // Inflate all children.
                        rInflateChildren(childParser, view, childAttrs, true);

                        if (id != View.NO_ID) {
                            view.setId(id);
                        }

                        switch (visibility) {
                            case 0:
                                view.setVisibility(View.VISIBLE);
                                break;
                            case 1:
                                view.setVisibility(View.INVISIBLE);
                                break;
                            case 2:
                                view.setVisibility(View.GONE);
                                break;
                        }

                        group.addView(view);
                    }
                } finally {
                    childParser.close();
                }
            }
        } else {
            throw new InflateException("<include /> can only be used inside of a ViewGroup");
        }

        LayoutInflater.consumeChildElements(parser);
    }

    
Note: default visibility so that
LayoutInflater_Delegate can call it.
/**
     * <strong>Note:</strong> default visibility so that
     * LayoutInflater_Delegate can call it.
     */
    final static void consumeChildElements(XmlPullParser parser)
            throws XmlPullParserException, IOException {
        int type;
        final int currentDepth = parser.getDepth();
        while (((type = parser.next()) != XmlPullParser.END_TAG ||
                parser.getDepth() > currentDepth) && type != XmlPullParser.END_DOCUMENT) {
            // Empty
        }
    }

    private static class BlinkLayout extends FrameLayout {
        private static final int MESSAGE_BLINK = 0x42;
        private static final int BLINK_DELAY = 500;

        private boolean mBlink;
        private boolean mBlinkState;
        private final Handler mHandler;

        public BlinkLayout(Context context, AttributeSet attrs) {
            super(context, attrs);
            mHandler = new Handler(new Handler.Callback() {
                @Override
                public boolean handleMessage(Message msg) {
                    if (msg.what == MESSAGE_BLINK) {
                        if (mBlink) {
                            mBlinkState = !mBlinkState;
                            makeBlink();
                        }
                        invalidate();
                        return true;
                    }
                    return false;
                }
            });
        }

        private void makeBlink() {
            Message message = mHandler.obtainMessage(MESSAGE_BLINK);
            mHandler.sendMessageDelayed(message, BLINK_DELAY);
        }

        @Override
        protected void onAttachedToWindow() {
            super.onAttachedToWindow();

            mBlink = true;
            mBlinkState = true;

            makeBlink();
        }

        @Override
        protected void onDetachedFromWindow() {
            super.onDetachedFromWindow();

            mBlink = false;
            mBlinkState = true;

            mHandler.removeMessages(MESSAGE_BLINK);
        }

        @Override
        protected void dispatchDraw(Canvas canvas) {
            if (mBlinkState) {
                super.dispatchDraw(canvas);
            }
        }
    }
}