我正在创建一个通过流媒体播放歌曲的应用程序。移动到后台时，我的应用程序将继续播放，这没问题。但是，当其他一些应用程序（如设备的音乐播放器）或者可能是当我当时正在播放来自 youtube 的视频时，两个媒体都重叠并且它不会进入 onAudioFocusChange() 相同的代码：
public class sampleMediaPlayer extends Activity implements AudioManager.OnAudioFocusChangeListener, OnClickListener {
private MediaPlayer mediaPlayer;
private String myURL;
AudioManager audioManager;
Button buttonStart, buttonStop;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
buttonStart = (Button) findViewById(R.id.buttonStart);
buttonStop = (Button) findViewById(R.id.buttonStop);
buttonStart.setOnClickListener(this);
buttonStop.setOnClickListener(this);
audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
}
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
Log.e("123", "Inside sampleMediaPlayer");
}
@Override
protected void onStop() {
// TODO Auto-generated method stub
super.onStop();
}
@Override
public void onAudioFocusChange(int focusChange) {
// TODO Auto-generated method stub
Log.e("123", "focusChange============>>>>"+focusChange);
switch (focusChange) {
case AudioManager.AUDIOFOCUS_GAIN:
Log.e("123", "focusChange======AUDIOFOCUS_GAIN======>>>>"+focusChange);
requestFocus();
// resume playback
//AUDIOFOCUS_GAIN (1) : audio focus, or a request of audio focus, of unknown duration.
if (mediaPlayer == null)
initMediaPlayer();
else if (!mediaPlayer.isPlaying())
mediaPlayer.start();
mediaPlayer.setVolume(1.0f, 1.0f);
break;
case AudioManager.AUDIOFOCUS_GAIN_TRANSIENT:
//AUDIOFOCUS_GAIN_TRANSIENT (2) : temporary gain or request of audio focus, e.g. event notification
Log.e("123", "focusChange=======AUDIOFOCUS_GAIN_TRANSIENT=====>>>>"+focusChange);
// requestFocus();
// if (!mediaPlayer.isPlaying())
// mediaPlayer.start();
break;
case AudioManager.AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK:
//AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK (3) : temporary request of audio focus, anticipated to last a short amount of time,
//and where it is acceptable for other audio applications to keep playing after having lowered their output level,
//e.g. playback of driving directions where playback of music in the background is acceptable.
Log.e("123", "focusChange=======AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK=====>>>>"+focusChange);
// requestFocus();
break;
case AudioManager.AUDIOFOCUS_LOSS:
// Lost focus for an unbounded amount of time: stop playback and release media player
// -1
Log.e("123", "focusChange=====AUDIOFOCUS_LOSS=======>>>>"+focusChange);
if (mediaPlayer.isPlaying())
mediaPlayer.stop();
mediaPlayer.release();
mediaPlayer = null;
abandonFocus();
break;
case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT:
Log.e("123", "focusChange======AUDIOFOCUS_LOSS_TRANSIENT======>>>>"+focusChange);
// Lost focus for a short time, but we have to stop
// playback. We don't release the media player because playback
// is likely to resume
//-2
if (mediaPlayer.isPlaying())
mediaPlayer.pause();
abandonFocus();
break;
case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK:
Log.e("123", "focusChange======AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK======>>>>"+focusChange);
// Lost focus for a short time, but it's ok to keep playing
// at an attenuated level
//-3
if (mediaPlayer.isPlaying())
mediaPlayer.setVolume(0.1f, 0.1f);
break;
}
}
@SuppressLint("NewApi")
private void initMediaPlayer() {
// TODO Auto-generated method stub
if(mediaPlayer==null)
mediaPlayer = new MediaPlayer();
//mediaPlayer = MediaPlayer.create(this, R.raw.braincandy);
try {
if(!mediaPlayer.isPlaying()){
mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
myURL = "http://202.191.185.2:10406/thathi_thathi.mp3";
mediaPlayer.setDataSource(myURL);
mediaPlayer.prepare();
}
int result = audioManager.requestAudioFocus(this, AudioManager.STREAM_MUSIC, AudioManager.AUDIOFOCUS_GAIN);
boolean flag = requestFocus();
Log.e("123", "result===============>>>"+result);
if (result != AudioManager.AUDIOFOCUS_REQUEST_GRANTED && flag==true) {
// could not get audio focus.
Toast.makeText(this, "AudioFocus Request Failed", Toast.LENGTH_SHORT).show();
}else if(result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED){
Toast.makeText(this, "AudioFocus Request Granted", Toast.LENGTH_SHORT).show();
}
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
Log.e("123", "Illegal Argument Exception");
e.printStackTrace();
} catch (SecurityException e) {
// TODO Auto-generated catch block
Log.e("123", "Security Ecxeption");
e.printStackTrace();
//}
} catch (IOException e) {
// TODO Auto-generated catch block
Log.e("123", "IO Exception----------");
e.printStackTrace();
}
// setAudioManager();
mediaPlayer.start();
Log.e("123", "Media Player started");
}
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
switch (arg0.getId()) {
case R.id.buttonStart:
Log.d("123", "onClick: starting srvice");
// startService(new Intent(this, MyService.class));
// afh.requestFocus();
requestFocus();
initMediaPlayer();
break;
case R.id.buttonStop:
Log.d("123", "onClick: stopping srvice");
// stopService(new Intent(this, MyService.class));
//afh.abandonFocus();
if(mediaPlayer != null){
mediaPlayer.stop();
mediaPlayer.release();
abandonFocus();
}
break;
}
}
public boolean requestFocus() {
return AudioManager.AUDIOFOCUS_REQUEST_GRANTED ==
audioManager.requestAudioFocus(this, AudioManager.STREAM_MUSIC,
AudioManager.AUDIOFOCUS_GAIN);
}
public boolean abandonFocus() {
return AudioManager.AUDIOFOCUS_REQUEST_GRANTED ==
audioManager.abandonAudioFocus(this);
}
}