任何方式來檢測音量按鍵或音量變化與android服務？

Question

某些Android應用程序在設備的音量發生變化並且某些設備鎖定音量時會生成通知。對於我的生活，我無法找到如何做到這一點。請有人幫我提供一個例子嗎？

Answer 1

沒有廣播事件檢測量的變化，但也許你可以每隔一兩個秒鐘檢查體積就是用getStreamVolume，如果你需要在一個特定的音量鎖定，每隔一兩秒鐘用途：setStreamVolume

有關更多信息，請檢查http://developer.android.com/reference/android/media/AudioManager.htm。

您可以使用AlarmManager類或處理程序每​​隔一秒左右檢查一次音量。

如果這是一項活動，您可以覆蓋onKeyDown以檢測按鍵。請參閱http://developer.android.com/reference/android/view/View.html

Answer 2

實際上，您可以使用Content Observer在服務中執行某種操作。它像一個廣播接收器，聽變化的內容，如音量，接觸的情況下，通話記錄......

使用下面的代碼在服務

public class VolumeService extends Service{ 
AudioManager mAudioManager; 
Handler mHandler; 

private ContentObserver mVolumeObserver = new ContentObserver(mHandler) { 
    @Override 
    public void onChange(boolean selfChange) { 
     super.onChange(selfChange); 
     if (mAudioManager != null) { 

      final int volume = mAudioManager.getStreamVolume(AudioManager.STREAM_RING); 
      System.out.println("Volume thay đổi: " +volume); 

      Intent photoIntent = new Intent(VolumeService.this,TakePhotoActivity.class); 
      photoIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); 
      startActivity(photoIntent); 
     } 
    } 
}; 





@Override 
public void onCreate() { 
    super.onCreate(); 

    System.out.println("Volume Service started"); 

    mAudioManager = (AudioManager) getSystemService(AUDIO_SERVICE); 

    Uri uri = Settings.System.getUriFor(Settings.System.VOLUME_SETTINGS[AudioManager.STREAM_RING]); 
    getContentResolver().registerContentObserver(uri, true, mVolumeObserver); 

    System.out.println("Đã đăng ký Volume listener"); 
} 



@Override 
public void onDestroy() { 
    super.onDestroy();  
    System.out.println("Volume service destroied"); 

    getContentResolver().unregisterContentObserver(mVolumeObserver); 
} 



@Override 
public IBinder onBind(Intent arg0) { 

    return null; 
} 

} 

不要忘了將它聲明在Android Manifest.xml中

<service android:name=".service.VolumeService" > 

Answer 3

這是一種方法，您可以只修改設置的音量而不是更改。我的目標是調整系統容量服務。

此外，請避免僅在需要時進行此操作。

public class VolumeKeyController { 

    private MediaSessionCompat mMediaSession; 
    private final Context mContext; 

    public VolumeKeyController(Context context) { 
     mContext = context; 
    } 

    private void createMediaSession() { 
     mMediaSession = new MediaSessionCompat(mContext, KeyUtil.log); 

     mMediaSession.setFlags(MediaSessionCompat.FLAG_HANDLES_MEDIA_BUTTONS | 
       MediaSessionCompat.FLAG_HANDLES_TRANSPORT_CONTROLS); 
     mMediaSession.setPlaybackState(new Builder() 
       .setState(PlaybackStateCompat.STATE_PLAYING, 0, 0) 
       .build()); 
     mMediaSession.setPlaybackToRemote(getVolumeProvider()); 
     mMediaSession.setActive(true); 
    } 

    private VolumeProviderCompat getVolumeProvider() { 
     final AudioManager audio = mContext.getSystemService(Context.AUDIO_SERVICE); 

     int STREAM_TYPE = AudioManager.STREAM_MUSIC; 
     int currentVolume = audio.getStreamVolume(STREAM_TYPE); 
     int maxVolume = audio.getStreamMaxVolume(STREAM_TYPE); 
     final int VOLUME_UP = 1; 
     final int VOLUME_DOWN = -1; 

     return new VolumeProviderCompat(VolumeProviderCompat.VOLUME_CONTROL_RELATIVE, maxVolume, currentVolume) { 
      @Override 
      public void onAdjustVolume(int direction) { 
       // Up = 1, Down = -1, Release = 0 
       // Replace with your action, if you don't want to adjust system volume 
       if (direction == VOLUME_UP) { 
        audio.adjustStreamVolume(STREAM_TYPE, 
          AudioManager.ADJUST_RAISE, AudioManager.FLAG_REMOVE_SOUND_AND_VIBRATE); 
       } 
       else if (direction == VOLUME_DOWN) { 
        audio.adjustStreamVolume(STREAM_TYPE, 
          AudioManager.ADJUST_LOWER, AudioManager.FLAG_REMOVE_SOUND_AND_VIBRATE); 
       } 
       setCurrentVolume(audio.getStreamVolume(STREAM_TYPE)); 
      } 
     }; 
    } 

    // Call when control needed, add a call to constructor if needed immediately 
    public void setActive(boolean active) { 
     if (mMediaSession != null) { 
      mMediaSession.setActive(active); 
      return; 
     } 
     createMediaSession(); 
    } 

    // Call from Service's onDestroy method 
    public void destroy() { 
     if (mMediaSession != null) { 
      mMediaSession.release(); 
     } 
    } 
}