1 files changed, 99 insertions, 0 deletions
diff --git a/android/animation/TimeAnimator.java b/android/animation/TimeAnimator.java
new file mode 100644
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--- /dev/null
+++ b/android/animation/TimeAnimator.java
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+/*
+ * 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 android.animation;
+
+import android.view.animation.AnimationUtils;
+
+/**
+ * This class provides a simple callback mechanism to listeners that is synchronized with all
+ * other animators in the system. There is no duration, interpolation, or object value-setting
+ * with this Animator. Instead, it is simply started, after which it proceeds to send out events
+ * on every animation frame to its TimeListener (if set), with information about this animator,
+ * the total elapsed time, and the elapsed time since the previous animation frame.
+ */
+public class TimeAnimator extends ValueAnimator {
+
+    private TimeListener mListener;
+    private long mPreviousTime = -1;
+
+    @Override
+    public void start() {
+        mPreviousTime = -1;
+        super.start();
+    }
+
+    @Override
+    boolean animateBasedOnTime(long currentTime) {
+        if (mListener != null) {
+            long totalTime = currentTime - mStartTime;
+            long deltaTime = (mPreviousTime < 0) ? 0 : (currentTime - mPreviousTime);
+            mPreviousTime = currentTime;
+            mListener.onTimeUpdate(this, totalTime, deltaTime);
+        }
+        return false;
+    }
+
+    @Override
+    public void setCurrentPlayTime(long playTime) {
+        long currentTime = AnimationUtils.currentAnimationTimeMillis();
+        mStartTime = Math.max(mStartTime, currentTime - playTime);
+        mStartTimeCommitted = true; // do not allow start time to be compensated for jank
+        animateBasedOnTime(currentTime);
+    }
+
+    /**
+     * Sets a listener that is sent update events throughout the life of
+     * an animation.
+     *
+     * @param listener the listener to be set.
+     */
+    public void setTimeListener(TimeListener listener) {
+        mListener = listener;
+    }
+
+    @Override
+    void animateValue(float fraction) {
+        // Noop
+    }
+
+    @Override
+    void initAnimation() {
+        // noop
+    }
+
+    /**
+     * Implementors of this interface can set themselves as update listeners
+     * to a <code>TimeAnimator</code> instance to receive callbacks on every animation
+     * frame to receive the total time since the animator started and the delta time
+     * since the last frame. The first time the listener is called,
+     * deltaTime will be zero. The same is true for totalTime, unless the animator was
+     * set to a specific {@link ValueAnimator#setCurrentPlayTime(long) currentPlayTime}
+     * prior to starting.
+     */
+    public static interface TimeListener {
+        /**
+         * <p>Notifies listeners of the occurrence of another frame of the animation,
+         * along with information about the elapsed time.</p>
+         *
+         * @param animation The animator sending out the notification.
+         * @param totalTime The total time elapsed since the animator started, in milliseconds.
+         * @param deltaTime The time elapsed since the previous frame, in milliseconds.
+         */
+        void onTimeUpdate(TimeAnimator animation, long totalTime, long deltaTime);
+
+    }
+}