Продолжайте воспроизведение музыки при выключении экрана

Question

Я хочу продолжить воспроизведение музыки, даже если экран отключается (даже если пользователь блокирует свой телефон), пауза, когда пользователь нажимает кнопку «домой» и снова возвращается в приложение, должен позволить ему продолжать, откуда он остановился ... похож на пользователь, играющей музыку через файловый браузер ....

Вот мой код:

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

в основном для достижения вашей цели, вы не должны делать play3.pause в onPause() заявления :

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

Прямо сейчас, когда ваше приложение входит в состояние onPause, ваше воспроизведение приостанавливается. Btw не забудьте провести некоторое время и реализовать обработку AudioFocus.

Answer 2

Я узнал все о AudioFocus и это обработка из этих источников:

Media playback the right way (Big Android BBQ 2015)

How to properly handle audio interruptions

Managing Audio Focus

AudioManager

AudioManager.OnAudioFocusChangeListener

И в довесок, здесь есть информация о очистке медиа-ресурсов для вашего приложения, чтобы не съесть кучу памяти и освободить медиа кодек для других приложений, в случае, если они хотят, чтобы использовать его тоже:

Releasing the MediaPlayer

Cleaning up MediaPlayer resources

Answer 3

В проигрывателе деятельности до 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(); 
     } 
    } 
}; 

внутри onClick метода:

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); 
      } 

Также я предлагаю вам добавить к вашей активности игроков (но не внутри onCreate) для того, чтобы освободить медиа-ресурсов должным образом, и использовать его при нажатии кнопки Стоп прикоснулся и в других случаях, когда воспроизведение должно быть остановлено:

/** 
* 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); 
    } 
}