/*
 * Copyright (C) 2015 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.support.graphics.drawable;

import android.animation.Animator;
import android.animation.AnimatorInflater;
import android.animation.AnimatorSet;
import android.animation.ArgbEvaluator;
import android.animation.ObjectAnimator;
import android.annotation.TargetApi;
import android.content.Context;
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.PorterDuff;
import android.graphics.Rect;
import android.graphics.drawable.Animatable;
import android.graphics.drawable.AnimatedVectorDrawable;
import android.graphics.drawable.Drawable;
import android.os.Build;
import android.support.annotation.DrawableRes;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.content.res.ResourcesCompat;
import android.support.v4.graphics.drawable.DrawableCompat;
import android.support.v4.util.ArrayMap;
import android.util.AttributeSet;
import android.util.Log;
import android.util.Xml;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * This class uses {@link android.animation.ObjectAnimator} and
 * {@link android.animation.AnimatorSet} to animate the properties of a
 * {@link VectorDrawableCompat} to create an animated drawable.
 * <p>
 * AnimatedVectorDrawableCompat are normally defined as 3 separate XML files.
 * </p>
 * <p>
 * First is the XML file for {@link VectorDrawableCompat}. Note that we
 * allow the animation to happen on the group's attributes and path's attributes, which requires they
 * are uniquely named in this XML file. Groups and paths without animations do not need names.
 * </p>
 * <li>Here is a simple VectorDrawable in this vectordrawable.xml file.
 * <pre>
 * &lt;vector xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
 *     android:height=&quot;64dp&quot;
 *     android:width=&quot;64dp&quot;
 *     android:viewportHeight=&quot;600&quot;
 *     android:viewportWidth=&quot;600&quot; &gt;
 *     &lt;group
 *         android:name=&quot;rotationGroup&quot;
 *         android:pivotX=&quot;300.0&quot;
 *         android:pivotY=&quot;300.0&quot;
 *         android:rotation=&quot;45.0&quot; &gt;
 *         &lt;path
 *             android:name=&quot;v&quot;
 *             android:fillColor=&quot;#000000&quot;
 *             android:pathData=&quot;M300,70 l 0,-70 70,70 0,0 -70,70z&quot; /&gt;
 *     &lt;/group&gt;
 * &lt;/vector&gt;
 * </pre></li>
 * <p>
 * Second is the AnimatedVectorDrawableCompat's XML file, which defines the target
 * VectorDrawableCompat, the target paths and groups to animate, the properties of the path and
 * group to animate and the animations defined as the ObjectAnimators or AnimatorSets.
 * </p>
 * <li>Here is a simple AnimatedVectorDrawable defined in this avd.xml file.
 * Note how we use the names to refer to the groups and paths in the vectordrawable.xml.
 * <pre>
 * &lt;animated-vector xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
 *   android:drawable=&quot;@drawable/vectordrawable&quot; &gt;
 *     &lt;target
 *         android:name=&quot;rotationGroup&quot;
 *         android:animation=&quot;@anim/rotation&quot; /&gt;
 *     &lt;target
 *         android:name=&quot;v&quot;
 *         android:animation=&quot;@anim/path_morph&quot; /&gt;
 * &lt;/animated-vector&gt;
 * </pre></li>
 * <p>
 * Last is the Animator XML file, which is the same as a normal ObjectAnimator or AnimatorSet. To
 * complete this example, here are the 2 animator files used in avd.xml: rotation.xml and
 * path_morph.xml.
 * </p>
 * <li>Here is the rotation.xml, which will rotate the target group for 360 degrees.
 * <pre>
 * &lt;objectAnimator
 *     android:duration=&quot;6000&quot;
 *     android:propertyName=&quot;rotation&quot;
 *     android:valueFrom=&quot;0&quot;
 *     android:valueTo=&quot;360&quot; /&gt;
 * </pre></li>
 * <li>Here is the path_morph.xml, which will morph the path from one shape to
 * the other. Note that the paths must be compatible for morphing.
 * In more details, the paths should have exact same length of commands, and
 * exact same length of parameters for each commands.
 * Note that the path strings are better stored in strings.xml for reusing.
 * <pre>
 * &lt;set xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;&gt;
 *     &lt;objectAnimator
 *         android:duration=&quot;3000&quot;
 *         android:propertyName=&quot;pathData&quot;
 *         android:valueFrom=&quot;M300,70 l 0,-70 70,70 0,0   -70,70z&quot;
 *         android:valueTo=&quot;M300,70 l 0,-70 70,0  0,140 -70,0 z&quot;
 *         android:valueType=&quot;pathType&quot;/&gt;
 * &lt;/set&gt;
 * </pre></li>
 *
 * @attr ref android.R.styleable#AnimatedVectorDrawableCompat_drawable
 * @attr ref android.R.styleable#AnimatedVectorDrawableCompatTarget_name
 * @attr ref android.R.styleable#AnimatedVectorDrawableCompatTarget_animation
 */
@TargetApi(Build.VERSION_CODES.LOLLIPOP)
public class AnimatedVectorDrawableCompat extends VectorDrawableCommon implements Animatable {
    private static final String LOGTAG = "AnimatedVDCompat";

    private static final String ANIMATED_VECTOR = "animated-vector";
    private static final String TARGET = "target";

    private static final boolean DBG_ANIMATION_VECTOR_DRAWABLE = false;

    private AnimatedVectorDrawableCompatState mAnimatedVectorState;

    private Context mContext;

    private ArgbEvaluator mArgbEvaluator = null;

    AnimatedVectorDrawableDelegateState mCachedConstantStateDelegate;

    private AnimatedVectorDrawableCompat() {
        this(null, null, null);
    }

    private AnimatedVectorDrawableCompat(@Nullable Context context) {
        this(context, null, null);
    }

    private AnimatedVectorDrawableCompat(@Nullable Context context,
                                         @Nullable AnimatedVectorDrawableCompatState state,
                                         @Nullable Resources res) {
        mContext = context;
        if (state != null) {
            mAnimatedVectorState = state;
        } else {
            mAnimatedVectorState = new AnimatedVectorDrawableCompatState(context, state, mCallback,
                    res);
        }
    }

    @Override
    public Drawable mutate() {
        if (mDelegateDrawable != null) {
            mDelegateDrawable.mutate();
            return this;
        }
        throw new IllegalStateException("Mutate() is not supported for older platform");
    }


    /**
     * Create a AnimatedVectorDrawableCompat object.
     *
     * @param context the context for creating the animators.
     * @param resId   the resource ID for AnimatedVectorDrawableCompat object.
     * @return a new AnimatedVectorDrawableCompat or null if parsing error is found.
     */
    @Nullable
    public static AnimatedVectorDrawableCompat create(@NonNull Context context,
                                                      @DrawableRes int resId) {
        if (Build.VERSION.SDK_INT >= 21) {
            final AnimatedVectorDrawableCompat drawable = new AnimatedVectorDrawableCompat(context);
            drawable.mDelegateDrawable = ResourcesCompat.getDrawable(context.getResources(), resId,
                    context.getTheme());
            drawable.mDelegateDrawable.setCallback(drawable.mCallback);
            drawable.mCachedConstantStateDelegate = new AnimatedVectorDrawableDelegateState(
                    drawable.mDelegateDrawable.getConstantState());
            return drawable;
        }
        Resources resources = context.getResources();
        try {
            final XmlPullParser parser = resources.getXml(resId);
            final AttributeSet attrs = Xml.asAttributeSet(parser);
            int type;
            while ((type = parser.next()) != XmlPullParser.START_TAG
                    && type != XmlPullParser.END_DOCUMENT) {
                // Empty loop
            }
            if (type != XmlPullParser.START_TAG) {
                throw new XmlPullParserException("No start tag found");
            }
            return createFromXmlInner(context, context.getResources(), parser, attrs,
                    context.getTheme());
        } catch (XmlPullParserException e) {
            Log.e(LOGTAG, "parser error", e);
        } catch (IOException e) {
            Log.e(LOGTAG, "parser error", e);
        }
        return null;
    }

    /**
     * Create a AnimatedVectorDrawableCompat from inside an XML document using an optional
     * {@link Theme}. Called on a parser positioned at a tag in an XML
     * document, tries to create a Drawable from that tag. Returns {@code null}
     * if the tag is not a valid drawable.
     */
    public static AnimatedVectorDrawableCompat createFromXmlInner(Context context, Resources r,
            XmlPullParser parser, AttributeSet attrs, Theme theme)
            throws XmlPullParserException, IOException {
        final AnimatedVectorDrawableCompat drawable = new AnimatedVectorDrawableCompat(context);
        drawable.inflate(r, parser, attrs, theme);
        return drawable;
    }

    /**
     * {@inheritDoc}
     * <strong>Note</strong> that we don't support constant state when SDK < 21.
     * Make sure you check the return value before using it.
     */
    @Override
    public ConstantState getConstantState() {
        if (mDelegateDrawable != null) {
            return new AnimatedVectorDrawableDelegateState(mDelegateDrawable.getConstantState());
        }
        // We can't support constant state in older platform.
        // We need Context to create the animator, and we can't save the context in the constant
        // state.
        return null;
    }

    @Override
    public int getChangingConfigurations() {
        if (mDelegateDrawable != null) {
            return mDelegateDrawable.getChangingConfigurations();
        }
        return super.getChangingConfigurations() | mAnimatedVectorState.mChangingConfigurations;
    }

    @Override
    public void draw(Canvas canvas) {
        if (mDelegateDrawable != null) {
            mDelegateDrawable.draw(canvas);
            return;
        }
        mAnimatedVectorState.mVectorDrawable.draw(canvas);
        if (isStarted()) {
            invalidateSelf();
        }
    }

    @Override
    protected void onBoundsChange(Rect bounds) {
        if (mDelegateDrawable != null) {
            mDelegateDrawable.setBounds(bounds);
            return;
        }
        mAnimatedVectorState.mVectorDrawable.setBounds(bounds);
    }

    @Override
    protected boolean onStateChange(int[] state) {
        if (mDelegateDrawable != null) {
            return mDelegateDrawable.setState(state);
        }
        return mAnimatedVectorState.mVectorDrawable.setState(state);
    }

    @Override
    protected boolean onLevelChange(int level) {
        if (mDelegateDrawable != null) {
            return mDelegateDrawable.setLevel(level);
        }
        return mAnimatedVectorState.mVectorDrawable.setLevel(level);
    }

    @Override
    public int getAlpha() {
        if (mDelegateDrawable != null) {
            return DrawableCompat.getAlpha(mDelegateDrawable);
        }
        return mAnimatedVectorState.mVectorDrawable.getAlpha();
    }

    @Override
    public void setAlpha(int alpha) {
        if (mDelegateDrawable != null) {
            mDelegateDrawable.setAlpha(alpha);
            return;
        }
        mAnimatedVectorState.mVectorDrawable.setAlpha(alpha);
    }

    @Override
    public void setColorFilter(ColorFilter colorFilter) {
        if (mDelegateDrawable != null) {
            mDelegateDrawable.setColorFilter(colorFilter);
            return;
        }
        mAnimatedVectorState.mVectorDrawable.setColorFilter(colorFilter);
    }

    public void setTint(int tint) {
        if (mDelegateDrawable != null) {
            DrawableCompat.setTint(mDelegateDrawable, tint);
            return;
        }

        mAnimatedVectorState.mVectorDrawable.setTint(tint);
    }

    public void setTintList(ColorStateList tint) {
        if (mDelegateDrawable != null) {
            DrawableCompat.setTintList(mDelegateDrawable, tint);
            return;
        }

        mAnimatedVectorState.mVectorDrawable.setTintList(tint);
    }

    public void setTintMode(PorterDuff.Mode tintMode) {
        if (mDelegateDrawable != null) {
            DrawableCompat.setTintMode(mDelegateDrawable, tintMode);
            return;
        }

        mAnimatedVectorState.mVectorDrawable.setTintMode(tintMode);
    }

    @Override
    public boolean setVisible(boolean visible, boolean restart) {
        if (mDelegateDrawable != null) {
            return mDelegateDrawable.setVisible(visible, restart);
        }
        mAnimatedVectorState.mVectorDrawable.setVisible(visible, restart);
        return super.setVisible(visible, restart);
    }

    @Override
    public boolean isStateful() {
        if (mDelegateDrawable != null) {
            return mDelegateDrawable.isStateful();
        }
        return mAnimatedVectorState.mVectorDrawable.isStateful();
    }

    @Override
    public int getOpacity() {
        if (mDelegateDrawable != null) {
            return mDelegateDrawable.getOpacity();
        }
        return mAnimatedVectorState.mVectorDrawable.getOpacity();
    }

    public int getIntrinsicWidth() {
        if (mDelegateDrawable != null) {
            return mDelegateDrawable.getIntrinsicWidth();
        }
        return mAnimatedVectorState.mVectorDrawable.getIntrinsicWidth();
    }

    public int getIntrinsicHeight() {
        if (mDelegateDrawable != null) {
            return mDelegateDrawable.getIntrinsicHeight();
        }
        return mAnimatedVectorState.mVectorDrawable.getIntrinsicHeight();
    }

    /**
     * Obtains styled attributes from the theme, if available, or unstyled
     * resources if the theme is null.
     */
    static TypedArray obtainAttributes(
            Resources res, Theme theme, AttributeSet set, int[] attrs) {
        if (theme == null) {
            return res.obtainAttributes(set, attrs);
        }
        return theme.obtainStyledAttributes(set, attrs, 0, 0);
    }

    @Override
    public void inflate(Resources res, XmlPullParser parser, AttributeSet attrs, Theme theme)
            throws XmlPullParserException, IOException {
        if (mDelegateDrawable != null) {
            DrawableCompat.inflate(mDelegateDrawable, res, parser, attrs, theme);
            return;
        }
        int eventType = parser.getEventType();
        while (eventType != XmlPullParser.END_DOCUMENT) {
            if (eventType == XmlPullParser.START_TAG) {
                final String tagName = parser.getName();
                if (DBG_ANIMATION_VECTOR_DRAWABLE) {
                    Log.v(LOGTAG, "tagName is " + tagName);
                }
                if (ANIMATED_VECTOR.equals(tagName)) {
                    final TypedArray a =
                            obtainAttributes(res, theme, attrs,
                                    AndroidResources.styleable_AnimatedVectorDrawable);

                    int drawableRes = a.getResourceId(
                            AndroidResources.styleable_AnimatedVectorDrawable_drawable, 0);
                    if (DBG_ANIMATION_VECTOR_DRAWABLE) {
                        Log.v(LOGTAG, "drawableRes is " + drawableRes);
                    }
                    if (drawableRes != 0) {
                        VectorDrawableCompat vectorDrawable = VectorDrawableCompat.create(res,
                                drawableRes, theme);
                        vectorDrawable.setAllowCaching(false);
                        vectorDrawable.setCallback(mCallback);
                        if (mAnimatedVectorState.mVectorDrawable != null) {
                            mAnimatedVectorState.mVectorDrawable.setCallback(null);
                        }
                        mAnimatedVectorState.mVectorDrawable = vectorDrawable;
                    }
                    a.recycle();
                } else if (TARGET.equals(tagName)) {
                    final TypedArray a =
                            res.obtainAttributes(attrs,
                                    AndroidResources.styleable_AnimatedVectorDrawableTarget);
                    final String target = a.getString(
                            AndroidResources.styleable_AnimatedVectorDrawableTarget_name);

                    int id = a.getResourceId(
                            AndroidResources.styleable_AnimatedVectorDrawableTarget_animation, 0);
                    if (id != 0) {
                        if (mContext != null) {
                            Animator objectAnimator = AnimatorInflater.loadAnimator(mContext, id);
                            setupAnimatorsForTarget(target, objectAnimator);
                        } else {
                            throw new IllegalStateException("Context can't be null when inflating" +
                                    " animators");
                        }
                    }
                    a.recycle();
                }
            }

            eventType = parser.next();
        }
    }

    @Override
    public void inflate(Resources res, XmlPullParser parser, AttributeSet attrs)
            throws XmlPullParserException, IOException {
        inflate(res, parser, attrs, null);
    }

    @Override
    public void applyTheme(Theme t) {
        if (mDelegateDrawable != null) {
            DrawableCompat.applyTheme(mDelegateDrawable, t);
            return;
        }
        // TODO: support theming in older platform.
        return;
    }

    public boolean canApplyTheme() {
        if (mDelegateDrawable != null) {
            return DrawableCompat.canApplyTheme(mDelegateDrawable);
        }
        // TODO: support theming in older platform.
        return false;
    }

    /**
     * Constant state for delegating the creating drawable job.
     * Instead of creating a VectorDrawable, create a VectorDrawableCompat instance which contains
     * a delegated VectorDrawable instance.
     */
    private static class AnimatedVectorDrawableDelegateState extends ConstantState {
        private final ConstantState mDelegateState;

        public AnimatedVectorDrawableDelegateState(ConstantState state) {
            mDelegateState = state;
        }

        @Override
        public Drawable newDrawable() {
            AnimatedVectorDrawableCompat drawableCompat =
                    new AnimatedVectorDrawableCompat();
            drawableCompat.mDelegateDrawable = mDelegateState.newDrawable();
            drawableCompat.mDelegateDrawable.setCallback(drawableCompat.mCallback);
            return drawableCompat;
        }

        @Override
        public Drawable newDrawable(Resources res) {
            AnimatedVectorDrawableCompat drawableCompat =
                    new AnimatedVectorDrawableCompat();
            drawableCompat.mDelegateDrawable = mDelegateState.newDrawable(res);
            drawableCompat.mDelegateDrawable.setCallback(drawableCompat.mCallback);
            return drawableCompat;
        }

        @Override
        public Drawable newDrawable(Resources res, Theme theme) {
            AnimatedVectorDrawableCompat drawableCompat =
                    new AnimatedVectorDrawableCompat();
            drawableCompat.mDelegateDrawable = mDelegateState.newDrawable(res, theme);
            drawableCompat.mDelegateDrawable.setCallback(drawableCompat.mCallback);
            return drawableCompat;
        }

        @Override
        public boolean canApplyTheme() {
            return mDelegateState.canApplyTheme();
        }

        @Override
        public int getChangingConfigurations() {
            return mDelegateState.getChangingConfigurations();
        }
    }

    private static class AnimatedVectorDrawableCompatState extends ConstantState {
        int mChangingConfigurations;
        VectorDrawableCompat mVectorDrawable;
        ArrayList<Animator> mAnimators;
        ArrayMap<Animator, String> mTargetNameMap;

        public AnimatedVectorDrawableCompatState(Context context,
                AnimatedVectorDrawableCompatState copy, Callback owner, Resources res) {
            if (copy != null) {
                mChangingConfigurations = copy.mChangingConfigurations;
                if (copy.mVectorDrawable != null) {
                    final ConstantState cs = copy.mVectorDrawable.getConstantState();
                    if (res != null) {
                        mVectorDrawable = (VectorDrawableCompat) cs.newDrawable(res);
                    } else {
                        mVectorDrawable = (VectorDrawableCompat) cs.newDrawable();
                    }
                    mVectorDrawable = (VectorDrawableCompat) mVectorDrawable.mutate();
                    mVectorDrawable.setCallback(owner);
                    mVectorDrawable.setBounds(copy.mVectorDrawable.getBounds());
                    mVectorDrawable.setAllowCaching(false);
                }
                if (copy.mAnimators != null) {
                    final int numAnimators = copy.mAnimators.size();
                    mAnimators = new ArrayList<Animator>(numAnimators);
                    mTargetNameMap = new ArrayMap<Animator, String>(numAnimators);
                    for (int i = 0; i < numAnimators; ++i) {
                        Animator anim = copy.mAnimators.get(i);
                        Animator animClone = anim.clone();
                        String targetName = copy.mTargetNameMap.get(anim);
                        Object targetObject = mVectorDrawable.getTargetByName(targetName);
                        animClone.setTarget(targetObject);
                        mAnimators.add(animClone);
                        mTargetNameMap.put(animClone, targetName);
                    }
                }
            }
        }

        @Override
        public Drawable newDrawable() {
            throw new IllegalStateException("No constant state support for SDK < 21.");
        }

        @Override
        public Drawable newDrawable(Resources res) {
            throw new IllegalStateException("No constant state support for SDK < 21.");
        }

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

    /**
     * Utility function to fix color interpolation prior to Lollipop. Without this fix, colors
     * are evaluated as raw integers instead of as colors, which leads to artifacts during
     * fillColor animations.
     */
    private void setupColorAnimator(Animator animator) {
        if (animator instanceof AnimatorSet) {
            List<Animator> childAnimators = ((AnimatorSet) animator).getChildAnimations();
            if (childAnimators != null) {
                for (int i = 0; i < childAnimators.size(); ++i) {
                    setupColorAnimator(childAnimators.get(i));
                }
            }
        }
        if (animator instanceof ObjectAnimator) {
            ObjectAnimator objectAnim = (ObjectAnimator) animator;
            final String propertyName = objectAnim.getPropertyName();
            if ("fillColor".equals(propertyName) || "strokeColor".equals(propertyName)) {
                if (mArgbEvaluator == null) {
                    mArgbEvaluator = new ArgbEvaluator();
                }
                objectAnim.setEvaluator(mArgbEvaluator);
            }
        }
    }

    private void setupAnimatorsForTarget(String name, Animator animator) {
        Object target = mAnimatedVectorState.mVectorDrawable.getTargetByName(name);
        animator.setTarget(target);
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
            setupColorAnimator(animator);
        }
        if (mAnimatedVectorState.mAnimators == null) {
            mAnimatedVectorState.mAnimators = new ArrayList<Animator>();
            mAnimatedVectorState.mTargetNameMap = new ArrayMap<Animator, String>();
        }
        mAnimatedVectorState.mAnimators.add(animator);
        mAnimatedVectorState.mTargetNameMap.put(animator, name);
        if (DBG_ANIMATION_VECTOR_DRAWABLE) {
            Log.v(LOGTAG, "add animator  for target " + name + " " + animator);
        }
    }

    @Override
    public boolean isRunning() {
        if (mDelegateDrawable != null) {
            return ((AnimatedVectorDrawable) mDelegateDrawable).isRunning();
        }
        final ArrayList<Animator> animators = mAnimatedVectorState.mAnimators;
        final int size = animators.size();
        for (int i = 0; i < size; i++) {
            final Animator animator = animators.get(i);
            if (animator.isRunning()) {
                return true;
            }
        }
        return false;
    }

    private boolean isStarted() {
        final ArrayList<Animator> animators = mAnimatedVectorState.mAnimators;
        if (animators == null) {
            return false;
        }
        final int size = animators.size();
        for (int i = 0; i < size; i++) {
            final Animator animator = animators.get(i);
            if (animator.isRunning()) {
                return true;
            }
        }
        return false;
    }

    @Override
    public void start() {
        if (mDelegateDrawable != null) {
            ((AnimatedVectorDrawable) mDelegateDrawable).start();
            return;
        }
        // If any one of the animator has not ended, do nothing.
        if (isStarted()) {
            return;
        }
        // Otherwise, kick off every animator.
        final ArrayList<Animator> animators = mAnimatedVectorState.mAnimators;
        final int size = animators.size();
        for (int i = 0; i < size; i++) {
            final Animator animator = animators.get(i);
            animator.start();
        }
        invalidateSelf();
    }

    @Override
    public void stop() {
        if (mDelegateDrawable != null) {
            ((AnimatedVectorDrawable) mDelegateDrawable).stop();
            return;
        }
        final ArrayList<Animator> animators = mAnimatedVectorState.mAnimators;
        final int size = animators.size();
        for (int i = 0; i < size; i++) {
            final Animator animator = animators.get(i);
            animator.end();
        }
    }

    private final Callback mCallback = new Callback() {
        @Override
        public void invalidateDrawable(Drawable who) {
            invalidateSelf();
        }

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

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