MediaPlayer App用法

 

public class MainActivity extends Activity implements OnClickListener {

    private static final String TAG = "CM-MainActivity";
    private MediaPlayer mMediaPlayer = null;

    private Button mPlayBtn;
    private Button mStopBtn;
    boolean isPlaying = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        Log.d(TAG, "onCreate()");
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mPlayBtn = (Button) findViewById(R.id.play);
        mPlayBtn.setOnClickListener(this);
        mStopBtn = (Button) findViewById(R.id.stop);
        mStopBtn.setOnClickListener(this);
    }

    @Override
    protected void onDestroy() {
        if (isPlaying && mMediaPlayer != null) {
            Log.d(TAG, "stop()");
            mMediaPlayer.stop();
            mMediaPlayer.release();
            isPlaying = false;
        }

        super.onDestroy();
    }   

    @Override
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.play:
                if (mMediaPlayer == null) {
                    Log.d(TAG, "new MediaPlayer()");
                    mMediaPlayer = new MediaPlayer();

                } else {
                    Log.d(TAG, "reset()");
                    mMediaPlayer.reset();
                }

                try {
                    Log.d(TAG, "setDataSource()");
                    mMediaPlayer.setDataSource("/storage/sdcard0/cfy.mp3");
                    Log.d(TAG, "prepare()");
                    mMediaPlayer.prepare();
                    Log.d(TAG, "start()");
                    mMediaPlayer.start();
                    isPlaying = true;
                } catch (Exception e) {
                    e.printStackTrace();
                }

                break;
            case R.id.stop:
                if (mMediaPlayer != null) {
                    Log.d(TAG, "stop()");
                    mMediaPlayer.stop();
                    //mMediaPlayer.release(); //release后就结束了 再使用这个mMediaPlayer就会抛出异常，所以这句不要
                    isPlaying = false;
                }

                break;
        }
    }
}

 

 

release()后 mMediaPlayer ！= null  mMediaPlayer不能再被使用 除非重新new MediaPlayer()

 

offload模式下 session是MediaPlayer的标记，如果不给MediaPlayer重新赋值，那么session不会改变，但是output会变化。

04-15 12:46:52.159   347 19023 V AudioPolicyManager: startOutput() output 169, stream 3, session 162, drmFlag 00000000
04-15 12:46:58.825   347  1040 V AudioPolicyManager: stopOutput() output 169, stream 3, session 162, playbackId 0
04-15 12:47:03.091   347 19053 V AudioPolicyManager: startOutput() output 171, stream 3, session 162, drmFlag 00000000
04-15 12:47:04.763   347  1040 V AudioPolicyManager: stopOutput() output 171, stream 3, session 162, playbackId 0
04-15 12:47:12.090   347 19089 V AudioPolicyManager: startOutput() output 173, stream 3, session 162, drmFlag 00000000
04-15 12:47:16.543   347  1040 V AudioPolicyManager: stopOutput() output 173, stream 3, session 162, playbackId 0