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package android.animation;
/**
* This class provides a simple callback mechanism to listeners that is synchronized with other
* animators in the system. There is no duration, interpolation, or object value-setting
* with this Animator. Instead, it is simply started and 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 time since the last animation frame.
*
* @hide
*/
public class TimeAnimator extends ValueAnimator {
private TimeListener mListener;
private long mPreviousTime = -1;
@Override
boolean animationFrame(long currentTime) {
if (mPlayingState == STOPPED) {
mPlayingState = RUNNING;
if (mSeekTime < 0) {
mStartTime = currentTime;
} else {
mStartTime = currentTime - mSeekTime;
// Now that we're playing, reset the seek time
mSeekTime = -1;
}
}
if (mListener != null) {
long totalTime = currentTime - mStartTime;
long deltaTime = (mPreviousTime < 0) ? 0 : (currentTime - mPreviousTime);
mPreviousTime = currentTime;
mListener.onTimeUpdate(this, totalTime, deltaTime);
}
return false;
}
/**
* 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, totalTime and
* deltaTime should both be zero.
*
* @hide
*/
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
*/
void onTimeUpdate(TimeAnimator animation, long totalTime, long deltaTime);
}
}
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