MediaSeekBar.java 文件源码

@Override
public void onPlaybackStateChanged(PlaybackStateCompat state) {
    super.onPlaybackStateChanged(state);

    // If there's an ongoing animation, stop it now.
    if (mProgressAnimator != null) {
        mProgressAnimator.cancel();
        mProgressAnimator = null;
    }

    final int progress = state != null
            ? (int) state.getPosition()
            : 0;
    setProgress(progress);
    Log.d("nicole", "Set progress to: " + (progress / 1000.0f));

    // If the media is playing then the seekbar should follow it, and the easiest
    // way to do that is to create a ValueAnimator to update it so the bar reaches
    // the end of the media the same time as playback gets there (or close enough).
    if (state != null && state.getState() == PlaybackStateCompat.STATE_PLAYING) {
        final int timeToEnd = (int) ((getMax() - progress) / state.getPlaybackSpeed());

        mProgressAnimator = ValueAnimator.ofInt(progress, getMax())
                .setDuration(timeToEnd);
        mProgressAnimator.setInterpolator(new LinearInterpolator());
        mProgressAnimator.addUpdateListener(this);
        mProgressAnimator.start();
    }
}