当屏幕熄灭时继续播放音乐

Question

即使屏幕熄灭（即使用户锁定了手机），我仍想继续播放音乐，当用户按下主页按钮并再次返回到应用程序时应暂停从那里，他停顿了一下......类似用户通过文件浏览器播放音乐继续....

这里是我的代码：

public class prathmeshvara extends AppCompatActivity implements Runnable, View.OnClickListener, SeekBar.OnSeekBarChangeListener{ 
TextView tv25; 
Button b47, b48, but32; 
int count = 0; 
MediaPlayer play3; 
SeekBar seek_bar3; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_prathmeshvara); 
    ActionBar actionBar=getSupportActionBar(); 
    actionBar.setDisplayShowHomeEnabled(true); 
    actionBar.setIcon(R.mipmap.icon); 
    tv25 = (TextView) findViewById(R.id.textView25); 
    tv25.setText(Html.fromHtml(getString(R.string.twentyone))); 
    b47 = (Button) findViewById(R.id.b47); 
    b48 = (Button) findViewById(R.id.b48); 
    seek_bar3 = (SeekBar) findViewById(R.id.seekBar3); 
    seek_bar3.setOnSeekBarChangeListener(this); 
    seek_bar3.setEnabled(false); 
    but32 = (Button) findViewById(R.id.button32); 
    but32.setOnClickListener(this); 
} 

public void run() { 
    int currentPosition = play3.getCurrentPosition(); 
    final int total = play3.getDuration(); 
    while (play3 != null && currentPosition < total) { 
     try { 
      Thread.sleep(1000); 
      currentPosition = play3.getCurrentPosition(); 
     } catch (InterruptedException e) { 
      return; 
     } catch (Exception e) { 
      return; 
     } 
     seek_bar3.setProgress(currentPosition); 
    } 
} 

public void onClick(View v) { 
    if (v.equals(but32)) { 
     if (play3 == null) { 
      play3 = MediaPlayer.create(getApplicationContext(), R.raw.prathameshwara); 
      seek_bar3.setEnabled(true); 
     } 
     if (play3.isPlaying()) { 
      play3.pause(); 
      but32.setBackgroundResource(R.drawable.play); 
     } else { 
      play3.start(); 
      but32.setBackgroundResource(R.drawable.pause); 
      seek_bar3.setMax(play3.getDuration()); 
      new Thread(this).start(); 
     } 
    } 
    play3.setOnCompletionListener(new MediaPlayer.OnCompletionListener() { 
     @Override 
     public void onCompletion(MediaPlayer mp) { 
      play3.seekTo(0); 
      but32.setBackgroundResource(R.drawable.play); 
     } 
    }); 
} 

@Override 
protected void onPause() 
{ 
    super.onPause(); 
    if (play3!= null) 
    { 
     play3.pause(); 
    } 
} 

@Override 
protected void onResume() 
{ 
    super.onResume(); 
    if ((play3 != null) && (!play3.isPlaying())) { 
     but32.setBackgroundResource(R.drawable.play); 
     but32.setOnClickListener(this); 
    } 
} 
@Override 
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) { 
    try { 
     if (play3.isPlaying() || play3 != null) { 
      if (fromUser) 
       play3.seekTo(progress); 
     } else if (play3 == null) { 
      Toast.makeText(getApplicationContext(), "First Play", Toast.LENGTH_SHORT).show(); 
      seek_bar3.setProgress(0); 
     } 
    } catch (Exception e) { 
     Log.e("seek bar", "" + e); 
     seek_bar3.setEnabled(false); 
    } 
} 

@Override 
public void onStartTrackingTouch(SeekBar seekBar) { 

} 

@Override 
public void onStopTrackingTouch(SeekBar seekBar) { 

} 
} 

Answer 1

基本上达到你的目标，你不应该在onPause()声明做play3.pause ：

@Override 
protected void onPause() 
{ 
    super.onPause(); 
    if (play3!= null) 
    { 
     play3.pause(); 
    } 
} 

当您的应用进入暂停状态时，您的播放暂停。 顺便说一句，不要忘了花一些时间和实现AudioFocus处理。

Answer 2

我已经学会了所有关于AudioFocus，并将其从这些来源处理：

Media playback the right way (Big Android BBQ 2015)

How to properly handle audio interruptions

Managing Audio Focus

AudioManager

AudioManager.OnAudioFocusChangeListener

而且，在makeweight，在这里你有关于清理媒体资源的开发为您的应用程序不是吃了一堆的内存和释放媒体编解码器的其他应用程序的情况下，他们想用它太一些信息：

Releasing the MediaPlayer

Cleaning up MediaPlayer resources

Answer 3

在你的玩家活动，前onCreate：

import android.media.AudioManager; 

...

/** Handles audio focus when playing a sound file */ 
private AudioManager mAudioManager; 

/** 
* This listener gets triggered when the {@link MediaPlayer} has completed 
* playing the audio file. 
*/ 


/** 
* This listener gets triggered whenever the audio focus changes 
* (i.e., we gain or lose audio focus because of another app or device). 
*/ 
private AudioManager.OnAudioFocusChangeListener mOnAudioFocusChangeListener = new AudioManager.OnAudioFocusChangeListener(){ 
    @Override 
    public void onAudioFocusChange(int focusChange){ 
     if (focusChange == AudioManager.AUDIOFOCUS_LOSS_TRANSIENT || 
       focusChange == AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK) { 
       // The AUDIOFOCUS_LOSS_TRANSIENT case means that we've lost audio focus for a 
       // short amount of time. The AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK case means that 
       // our app is allowed to continue playing sound but at a lower volume. We'll treat 
       // both cases the same way because our app is playing short sound files. 

       // Pause playback and reset player to the start of the file. That way, we can 
       // play the word from the beginning when we resume playback. 
       mMediaPlayer.pause(); 
       mMediaPlayer.seekTo(0); 
     } else if (focusChange == AudioManager.AUDIOFOCUS_GAIN) { 
       // The AUDIOFOCUS_GAIN case means we have regained focus and can resume playback. 
       mMediaPlayer.start(); 
     } else if (focusChange == AudioManager.AUDIOFOCUS_LOSS) { 
       // The AUDIOFOCUS_LOSS case means we've lost audio focus and 
       // Stop playback and clean up resources 
       releaseMediaPlayer(); 
     } 
    } 
}; 

的onClick方法中：

int result = mAudioManager.requestAudioFocus(mOnAudioFocusChangeListener, 
        AudioManager.STREAM_MUSIC, AudioManager.AUDIOFOCUS_GAIN_TRANSIENT); 

      if (result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED){ 
       // we have audio focus now 

       // Create and setup the {@link MediaPlayer} for the audio resource associated with the current word 
       mMediaPlayer = MediaPlayer.create(YourActivity.this, word.getAudioResourceId()); 

       // Start the audio file 
       mMediaPlayer.start(); 

       // Setup a listener on the media player, so that we can stop and release the 
       // media player once the sound has finished playing. 
       mMediaPlayer.setOnCompletionListener(mCompletionListener); 
      } 

此外，我建议你把它添加到您的播放器的活动（但不是内onCreate），以便正确地释放媒体资源，并使用它的时候停止按钮感动并在其他情况下播放时应停止：

/** 
* Clean up the media player by releasing its resources. 
*/ 
private void releaseMediaPlayer() { 
    // If the media player is not null, then it may be currently playing a sound. 
    if (mMediaPlayer != null) { 
     // Regardless of the current state of the media player, release its resources 
     // because we no longer need it. 
     mMediaPlayer.release(); 

     // Set the media player back to null. For our code, we've decided that 
     // setting the media player to null is an easy way to tell that the media player 
     // is not configured to play an audio file at the moment. 
     mMediaPlayer = null; 

     // Regardless of whether or not we were granted audio focus, abandon it. This also 
     // unregisters the AudioFocusChangeListener so we don't get anymore callbacks. 
     mAudioManager.abandonAudioFocus(mOnAudioFocusChangeListener); 
    } 
}