问题
I am having a problem with video playback on Android 4.4 on the Galaxy Tab 3. The issue did not occur with the previous Android version 4.2.
The issue
I am playing a video in a loop. This worked very well for all users, until the Tab 3 got updated to Android 4.4. Since then the video freezes after the first loop (it gets stuck on the first frame of the video to be precise).
I can reproduce that behaviour, and at the moment the video freezes my LogCat starts getting full with the following output:
16:25:25.239 14589-14601/my.app V/MediaPlayer? back from callback
16:25:25.499 14589-14686/my.app V/MediaPlayer? message received msg=7, ext1=0, ext2=0
16:25:25.499 14589-14686/my.app V/MediaPlayer? unrecognized message: (7, 0, 0)
16:25:25.499 14589-14686/my.app V/MediaPlayer? callback application
16:25:25.499 14589-14686/my.app V/MediaPlayer? back from callback
16:25:25.519 14589-14602/my.app V/MediaPlayer? message received msg=4, ext1=0, ext2=0
16:25:25.519 14589-14602/my.app V/MediaPlayer? Received seek complete
16:25:25.519 14589-14602/my.app V/MediaPlayer? All seeks complete - return to regularly scheduled program
16:25:25.519 14589-14602/my.app V/MediaPlayer? callback application
16:25:25.519 14589-14602/my.app V/MediaPlayer? back from callback
16:25:25.519 14589-14601/my.app V/MediaPlayer? message received msg=6, ext1=0, ext2=0
16:25:25.519 14589-14601/my.app V/MediaPlayer? Received MEDIA_STARTED
16:25:25.519 14589-14601/my.app V/MediaPlayer? callback application
16:25:25.519 14589-14601/my.app V/MediaPlayer? back from callback
16:25:25.789 14589-14686/my.app V/MediaPlayer? message received msg=7, ext1=0, ext2=0
16:25:25.789 14589-14686/my.app V/MediaPlayer? unrecognized message: (7, 0, 0)
16:25:25.789 14589-14686/my.app V/MediaPlayer? callback application
16:25:25.789 14589-14686/my.app V/MediaPlayer? back from callback
16:25:25.809 14589-14602/my.app V/MediaPlayer? message received msg=4, ext1=0, ext2=0
16:25:25.809 14589-14602/my.app V/MediaPlayer? Received seek complete
The code
The following (simplyfied) activity is supposed to play the video. MediaPlayer.OnErrorListener() and MediaPlayer.OnInfoListener() are never called.
public class VideoActivity extends Activity {
private MediaPlayer mediaPlayer;
private String videoPath = "some path obtained from the system";
// [...]
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mediaPlayer = new MediaPlayer();
startMovie();
}
private void startMovie(){
mediaPlayer.stop();
mediaPlayer.reset();
mediaPlayer.setLooping(true);
mediaPlayer.setDataSource(videoPath);
mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
@Override
public void onPrepared(MediaPlayer mp) {
mp.setWakeMode(getApplicationContext(), PowerManager.PARTIAL_WAKE_LOCK);
mp.start();
mp.seekTo(0);
}
});
mediaPlayer.prepare();
}
}
The video can be started several times with a different video file path during the lifetime of the activity, that's why I stop and reset the player before starting the movie.
So far the only solutions I found on the internet were to make sure the MediaPlayer is not collected by the GC (which I do by not making it a method-local object) and implement the WakeLock, which I also did without effect.
Can anyone please help me here and point me in the right direction? Thank you!
回答1:
More a workaround than a solution, I ended up not looping the video using the setLooping method of MediaPlayer. Instead I am now restarting the video in the OnCompletion callback of MediaPlayer. After a lot of trying this was the only way I got it to work across all devices I am testing on.
public class VideoActivity extends Activity {
private MediaPlayer mediaPlayer;
private String videoPath = "some path obtained from the system";
// [...]
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mediaPlayer = new MediaPlayer();
startMovie();
}
private void startMovie(){
mediaPlayer.stop();
mediaPlayer.reset();
mediaPlayer.setDataSource(videoPath);
mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
@Override
public void onPrepared(MediaPlayer mp) {
mp.setWakeMode(getApplicationContext(), PowerManager.PARTIAL_WAKE_LOCK);
mp.start();
mp.seekTo(0);
}
});
mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mp) {
startMovie();
}
});
mediaPlayer.prepare();
}
}
Still, if someone has a valid solution to that problem I will be happy to mark the corresponding answer as correct.
来源：https://stackoverflow.com/questions/26385336/mediaplayer-freezes-instead-of-looping-video-on-android-4-4