3029324 wip: Drop target crossfades as it moves from position to position

src/com/android/launcher2/InterruptibleInOutAnimator.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2010 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 com.android.launcher2;
+
+import android.animation.ValueAnimator;
+import android.util.Log;
+
+/**
+ * A convenience class for two-way animations, e.g. a fadeIn/fadeOut animation.
+ * With a regular ValueAnimator, if you call reverse to show the 'out' animation, you'll get
+ * a frame-by-frame mirror of the 'in' animation -- i.e., the interpolated values will
+ * be exactly reversed. Using this class, both the 'in' and the 'out' animation use the
+ * interpolator in the same direction.
+ */
+public class InterruptibleInOutAnimator extends ValueAnimator {
+    private long mOriginalDuration;
+    private Object mOriginalFromValue;
+    private Object mOriginalToValue;
+
+    public InterruptibleInOutAnimator(long duration, Object fromValue, Object toValue) {
+        super(duration, fromValue, toValue);
+        mOriginalDuration = duration;
+        mOriginalFromValue = fromValue;
+        mOriginalToValue = toValue;
+    }
+
+    private void animate(Object fromValue, Object toValue) {
+        // This only makes sense when it's running in the opposite direction, or stopped.
+        setDuration(mOriginalDuration - getCurrentPlayTime());
+
+        final Object startValue = isRunning() ? getAnimatedValue() : fromValue;
+        cancel();
+        setValues(startValue, toValue);
+        start();
+    }
+
+    /**
+     * This is the equivalent of calling Animator.start(), except that it can be called when
+     * the animation is running in the opposite direction, in which case we reverse
+     * direction and animate for a correspondingly shorter duration.
+     */
+    public void animateIn() {
+        animate(mOriginalFromValue, mOriginalToValue);
+    }
+
+    /**
+     * This is the roughly the equivalent of calling Animator.reverse(), except that it uses the
+     * same interpolation curve as animateIn(), rather than mirroring it. Also, like animateIn(),
+     * if the animation is currently running in the opposite direction, we reverse
+     * direction and animate for a correspondingly shorter duration.
+     */
+    public void animateOut() {
+        animate(mOriginalToValue, mOriginalFromValue);
+    }
+}