mediaplayer.create（）和mediaplayer.prepareAsync（）有什么区别？

Question

I have used the following code:

mp = MediaPlayer.create(this, Uri.parse("file://"+filePath));
mp.start(); 

This works fine. Then I wanted to play music from a folder

mp.setDataSource(this, Uri.parse("file://"+filePath));
mp.prepareAsync();
mp.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
                @Override
                public void onPrepared(MediaPlayer mp) {
                    mp.start();
                }
            });

Are there any performance differences between the two method?

Answer 1

The first approach ties up whatever thread you are on, long enough for MediaPlayer to read in the metadata of the media and prepare some buffers. If this is the main application thread, it means that your UI will be frozen while this is going on.

Answer 2

You can check MediaPlayer create() source code to see the difference:

 public static MediaPlayer create(Context context, Uri uri, SurfaceHolder holder,
        AudioAttributes audioAttributes, int audioSessionId) {

    try {
        MediaPlayer mp = new MediaPlayer();
        final AudioAttributes aa = audioAttributes != null ? audioAttributes :
            new AudioAttributes.Builder().build();
        mp.setAudioAttributes(aa);
        mp.setAudioSessionId(audioSessionId);
        mp.setDataSource(context, uri);
        if (holder != null) {
            mp.setDisplay(holder);
        }
        mp.prepare();
        return mp;
    } catch (IOException ex) {
        Log.d(TAG, "create failed:", ex);
        // fall through
    } catch (IllegalArgumentException ex) {
        Log.d(TAG, "create failed:", ex);
        // fall through
    } catch (SecurityException ex) {
        Log.d(TAG, "create failed:", ex);
        // fall through
    }

    return null;
}

Basically create() call is synchronous (it internally calls prepare() ) and prepareAsync() is asynchronous.

Answer 3

Sure, create method inits object in main thread. So code lines below it should wait for create.

On the other hand, prepare asynchronous opens a new thread to init object then notify you to run next operations while main thread run other lines.

Edit: As @CommonWares mentioned in the comment, mp.create() is a convenient method of calling mp.setDataSoucer() + mp.prepare() at the same time