Revert addition of add/removeAnimationListener

This reverts commit 02301df216
and 65d2171d00.

Dropped addition of new API because androidx's FragmentManagerImpl now
employs a workaround that removes the necessity to reflect into
mListener and doesn't need add/removeAnimationListener either.

Bug: 117519981
Test: atest AnimationTest
Change-Id: I7250570190f40f6c5da8ef65ed81b2d4bb815cf5

api/current.txt

@@ -52609,7 +52609,6 @@ package android.view.animation {
   public abstract class Animation implements java.lang.Cloneable {
     ctor public Animation();
     ctor public Animation(android.content.Context, android.util.AttributeSet);
-    method public void addAnimationListener(android.view.animation.Animation.AnimationListener);
     method protected void applyTransformation(float, android.view.animation.Transformation);
     method public void cancel();
     method protected android.view.animation.Animation clone() throws java.lang.CloneNotSupportedException;
@@ -52634,7 +52633,6 @@ package android.view.animation {
     method public void initialize(int, int, int, int);
     method public boolean isFillEnabled();
     method public boolean isInitialized();
-    method public void removeAnimationListener(android.view.animation.Animation.AnimationListener);
     method public void reset();
     method protected float resolveSize(int, float, int, int);
     method public void restrictDuration(long);

core/java/android/view/animation/Animation.java

@@ -23,6 +23,7 @@ import android.annotation.UnsupportedAppUsage;
 import android.content.Context;
 import android.content.res.TypedArray;
 import android.graphics.RectF;
+import android.os.Build;
 import android.os.Handler;
 import android.os.SystemProperties;
 import android.util.AttributeSet;
@@ -30,9 +31,6 @@ import android.util.TypedValue;
 
 import dalvik.system.CloseGuard;
 
-import java.util.ArrayList;
-import java.util.List;
-
 /**
  * Abstraction for an Animation that can be applied to Views, Surfaces, or
  * other objects. See the {@link android.view.animation animation package
@@ -187,14 +185,11 @@ public abstract class Animation implements Cloneable {
     /**
      * An animation listener to be notified when the animation starts, ends or repeats.
      */
-    @UnsupportedAppUsage
+    // If you need to chain the AnimationListener, wrap the existing Animation into an AnimationSet
+    // and add your new listener to that set
+    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 117519981)
     private AnimationListener mListener;
 
-    /**
-     * A list of animation listeners to be notified when the animation starts, ends or repeats.
-     */
-    private List<AnimationListener> mListeners;
-
     /**
      * Desired Z order mode during animation.
      */
@@ -833,7 +828,7 @@ public abstract class Animation implements Cloneable {
     }
 
     private boolean hasAnimationListener() {
-        return mListener != null || (mListeners != null && !mListeners.isEmpty());
+        return mListener != null;
     }
 
     /**
@@ -847,32 +842,6 @@ public abstract class Animation implements Cloneable {
         mListener = listener;
     }
 
-    /**
-     * <p>Adds an animation listener to this animation. The animation listener
-     * is notified of animation events such as the end of the animation or the
-     * repetition of the animation.</p>
-     *
-     * @param listener the animation listener to be notified
-     */
-    public void addAnimationListener(AnimationListener listener) {
-        if (mListeners == null) {
-            mListeners = new ArrayList<>(1);
-        }
-        mListeners.add(listener);
-    }
-
-    /**
-     * <p>Removes an animation listener that has been added with
-     * {@link #addAnimationListener(AnimationListener)}.</p>
-     *
-     * @param listener the animation listener to be removed
-     */
-    public void removeAnimationListener(AnimationListener listener) {
-        if (mListeners != null) {
-            mListeners.remove(listener);
-        }
-    }
-
     /**
      * Gurantees that this animation has an interpolator. Will use
      * a AccelerateDecelerateInterpolator is nothing else was specified.
@@ -1003,33 +972,18 @@ public abstract class Animation implements Cloneable {
         if (mListener != null) {
             mListener.onAnimationStart(this);
         }
-        if (mListeners != null && !mListeners.isEmpty()) {
-            for (AnimationListener listener : mListeners) {
-                listener.onAnimationStart(this);
-            }
-        }
     }
 
     void dispatchAnimationRepeat() {
         if (mListener != null) {
             mListener.onAnimationRepeat(this);
         }
-        if (mListeners != null && !mListeners.isEmpty()) {
-            for (AnimationListener listener : mListeners) {
-                listener.onAnimationRepeat(this);
-            }
-        }
     }
 
     void dispatchAnimationEnd() {
         if (mListener != null) {
             mListener.onAnimationEnd(this);
         }
-        if (mListeners != null && !mListeners.isEmpty()) {
-            for (AnimationListener listener : mListeners) {
-                listener.onAnimationEnd(this);
-            }
-        }
     }
 
     /**