Question

我正在编写一个小窗口小部件，只要用户更改铃声音量或振动设置，就需要更新。

捕获android.media.VIBRATE_SETTING_CHANGED对于振动设置效果很好，但是当振铃音量发生变化时我没有找到任何通知方式，尽管我可以尝试捕捉当用户按下音量增大/音量减小时物理键，还有许多其他选项可以在不使用这些键的情况下更改音量。

你知道是否有任何广播行动为此定义或以任何方式创建或没有它来解决问题？

Answer 1

没有广播操作，但我确实发现您可以连接内容观察者以在设置更改时收到通知，流量是其中一些设置。注册android.provider.Settings.System.CONTENT_URI以获得所有设置更改的通知：

mSettingsContentObserver = new SettingsContentObserver( new Handler() ); 
this.getApplicationContext().getContentResolver().registerContentObserver( 
    android.provider.Settings.System.CONTENT_URI, true, 
    mSettingsContentObserver );

内容观察者可能看起来像这样：

public class SettingsContentObserver extends ContentObserver {

   public SettingsContentObserver(Handler handler) {
      super(handler);
   } 

   @Override
   public boolean deliverSelfNotifications() {
      return super.deliverSelfNotifications(); 
   }

   @Override
   public void onChange(boolean selfChange) {
      super.onChange(selfChange);
      Log.v(LOG_TAG, "Settings change detected");
      updateStuff();
   }
}

请务必在某个时候取消注册内容观察者。

Answer 2

Nathan's code可以使用，但会为每个更改系统设置提供两个通知。为避免这种情况，请使用以下

public class SettingsContentObserver extends ContentObserver {
    int previousVolume;
    Context context;

    public SettingsContentObserver(Context c, Handler handler) {
        super(handler);
        context=c;

        AudioManager audio = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
        previousVolume = audio.getStreamVolume(AudioManager.STREAM_MUSIC);
    }

    @Override
    public boolean deliverSelfNotifications() {
        return super.deliverSelfNotifications();
    }

    @Override
    public void onChange(boolean selfChange) {
        super.onChange(selfChange);

        AudioManager audio = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
        int currentVolume = audio.getStreamVolume(AudioManager.STREAM_MUSIC);

        int delta=previousVolume-currentVolume;

        if(delta>0)
        {
            Logger.d("Decreased");
            previousVolume=currentVolume;
        }
        else if(delta<0)
        {
            Logger.d("Increased");
            previousVolume=currentVolume;
        }
    }
}

然后在您的服务onCreate中注册：

mSettingsContentObserver = new SettingsContentObserver(this,new Handler());
getApplicationContext().getContentResolver().registerContentObserver(android.provider.Settings.System.CONTENT_URI, true, mSettingsContentObserver );

然后在onDestroy中取消注册：

getApplicationContext().getContentResolver().unregisterContentObserver(mSettingsContentObserver);

Answer 3

是的，您可以注册一个接收器进行卷更改（这是一种破解，但有效），我设法这样做（不涉及ContentObserver）：在清单xml文件中：

<receiver android:name="com.example.myproject.receivers.MyReceiver" >
     <intent-filter>
          <action android:name="android.media.VOLUME_CHANGED_ACTION" />
     </intent-filter>
</receiver>

广播接收器：

public class MyReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        if (intent.getAction().equals("android.media.VOLUME_CHANGED_ACTION")) {
            Log.d("Music Stream", "has changed");       
        }
    }
}

希望它有所帮助！

Answer 4

基于Nathan's，adi's和swooby's code，我创建了一个完整的工作示例，并进行了一些小改进。

在AudioFragment课程中，我们可以看到使用自定义ContentObserver 监听音量变化是多么容易。

public class AudioFragment extends Fragment implements OnAudioVolumeChangedListener {

    private AudioVolumeObserver mAudioVolumeObserver;

    @Override
    public void onResume() {
        super.onResume();
        // initialize audio observer
        if (mAudioVolumeObserver == null) {
            mAudioVolumeObserver = new AudioVolumeObserver(getActivity());
        }
        /*
         * register audio observer to identify the volume changes
         * of audio streams for music playback.
         *
         * It is also possible to listen for changes in other audio stream types:
         * STREAM_RING: phone ring, STREAM_ALARM: alarms, STREAM_SYSTEM: system sounds, etc.
         */
        mAudioVolumeObserver.register(AudioManager.STREAM_MUSIC, this);
    }

    @Override
    public void onPause() {
        super.onPause();
        // release audio observer
        if (mAudioVolumeObserver != null) {
            mAudioVolumeObserver.unregister();
        }
    }

    @Override
    public void onAudioVolumeChanged(int currentVolume, int maxVolume) {
        Log.d("Audio", "Volume: " + currentVolume + "/" + maxVolume);
        Log.d("Audio", "Volume: " + (int) ((float) currentVolume / maxVolume) * 100 + "%");
    }
}

public class AudioVolumeContentObserver extends ContentObserver {

    private final OnAudioVolumeChangedListener mListener;
    private final AudioManager mAudioManager;
    private final int mAudioStreamType;
    private int mLastVolume;

    public AudioVolumeContentObserver(
            @NonNull Handler handler,
            @NonNull AudioManager audioManager,
            int audioStreamType,
            @NonNull OnAudioVolumeChangedListener listener) {

        super(handler);
        mAudioManager = audioManager;
        mAudioStreamType = audioStreamType;
        mListener = listener;
        mLastVolume = audioManager.getStreamVolume(mAudioStreamType);
    }

    /**
     * Depending on the handler this method may be executed on the UI thread
     */
    @Override
    public void onChange(boolean selfChange, Uri uri) {
        if (mAudioManager != null && mListener != null) {
            int maxVolume = mAudioManager.getStreamMaxVolume(mAudioStreamType);
            int currentVolume = mAudioManager.getStreamVolume(mAudioStreamType);
            if (currentVolume != mLastVolume) {
                mLastVolume = currentVolume;
                mListener.onAudioVolumeChanged(currentVolume, maxVolume);
            }
        }
    }

    @Override
    public boolean deliverSelfNotifications() {
        return super.deliverSelfNotifications();
    }
}

public class AudioVolumeObserver {

    private final Context mContext;
    private final AudioManager mAudioManager;
    private AudioVolumeContentObserver mAudioVolumeContentObserver;

    public AudioVolumeObserver(@NonNull Context context) {
        mContext = context;
        mAudioManager = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
    }

    public void register(int audioStreamType, 
                         @NonNull OnAudioVolumeChangedListener listener) {

        Handler handler = new Handler();
        // with this handler AudioVolumeContentObserver#onChange() 
        //   will be executed in the main thread
        // To execute in another thread you can use a Looper
        // +info: https://stackoverflow.com/a/35261443/904907

        mAudioVolumeContentObserver = new AudioVolumeContentObserver(
                handler,
                mAudioManager,
                audioStreamType,
                listener);

        mContext.getContentResolver().registerContentObserver(
                android.provider.Settings.System.CONTENT_URI,
                true,
                mAudioVolumeContentObserver);
    }

    public void unregister() {
        if (mAudioVolumeContentObserver != null) {
            mContext.getContentResolver().unregisterContentObserver(mAudioVolumeContentObserver);
            mAudioVolumeContentObserver = null;
        }
    }
}

public interface OnAudioVolumeChangedListener {

    void onAudioVolumeChanged(int currentVolume, int maxVolume);
}

希望它对某人有用！：）

Answer 5

Nathan和adi的代码有效，但可以清理和自包含到：

public class AudioStreamVolumeObserver
{
    public interface OnAudioStreamVolumeChangedListener
    {
        void onAudioStreamVolumeChanged(int audioStreamType, int volume);
    }

    private static class AudioStreamVolumeContentObserver
            extends ContentObserver
    {
        private final AudioManager                       mAudioManager;
        private final int                                mAudioStreamType;
        private final OnAudioStreamVolumeChangedListener mListener;

        private int mLastVolume;

        public AudioStreamVolumeContentObserver(
                @NonNull
                Handler handler,
                @NonNull
                AudioManager audioManager, int audioStreamType,
                @NonNull
                OnAudioStreamVolumeChangedListener listener)
        {
            super(handler);

            mAudioManager = audioManager;
            mAudioStreamType = audioStreamType;
            mListener = listener;

            mLastVolume = mAudioManager.getStreamVolume(mAudioStreamType);
        }

        @Override
        public void onChange(boolean selfChange)
        {
            int currentVolume = mAudioManager.getStreamVolume(mAudioStreamType);

            if (currentVolume != mLastVolume)
            {
                mLastVolume = currentVolume;

                mListener.onAudioStreamVolumeChanged(mAudioStreamType, currentVolume);
            }
        }
    }

    private final Context mContext;

    private AudioStreamVolumeContentObserver mAudioStreamVolumeContentObserver;

    public AudioStreamVolumeObserver(
            @NonNull
            Context context)
    {
        mContext = context;
    }

    public void start(int audioStreamType,
                      @NonNull
                      OnAudioStreamVolumeChangedListener listener)
    {
        stop();

        Handler handler = new Handler();
        AudioManager audioManager = (AudioManager) mContext.getSystemService(Context.AUDIO_SERVICE);

        mAudioStreamVolumeContentObserver = new AudioStreamVolumeContentObserver(handler, audioManager, audioStreamType, listener);

        mContext.getContentResolver()
                .registerContentObserver(System.CONTENT_URI, true, mAudioStreamVolumeContentObserver);
    }

    public void stop()
    {
        if (mAudioStreamVolumeContentObserver == null)
        {
            return;
        }

        mContext.getContentResolver()
                .unregisterContentObserver(mAudioStreamVolumeContentObserver);
        mAudioStreamVolumeContentObserver = null;
    }
}

Answer 6

如果仅更改振铃模式，则可以使用带有“android.media.RINGER_MODE_CHANGED”的广播接收器作为操作。它很容易实现

Answer 7

您好我尝试了上面的代码，它对我不起作用。但是，当我试图添加这一行

getActivity().setVolumeControlStream(AudioManager.STREAM_MUSIC);

并放

mSettingsContentObserver = new SettingsContentObserver(this,new Handler());
getApplicationContext().getContentResolver().registerContentObserver(android.provider.Settings.System.CONTENT_URI, true, mSettingsContentObserver );

现在有效。我关心的是如何隐藏卷对话框。请参阅此image。

Answer 8

  private const val EXTRA_VOLUME_STREAM_TYPE = "android.media.EXTRA_VOLUME_STREAM_TYPE"
  private const val VOLUME_CHANGED_ACTION = "android.media.VOLUME_CHANGED_ACTION"

    val filter = IntentFilter(VOLUME_CHANGED_ACTION)
    filter.addAction(RINGER_MODE_CHANGED_ACTION)

      val receiver = object : BroadcastReceiver() {
            override fun onReceive(context1: Context, intent: Intent) {

                val stream = intent.getIntExtra(EXTRA_VOLUME_STREAM_TYPE, UNKNOWN)
                val mode = intent.getIntExtra(EXTRA_RINGER_MODE, UNKNOWN)
                val volumeLevel = audioManager.getStreamVolume(stream)
            }
        }

Answer 9

在所有情况下均为100％工作方式

  public class SettingsContentObserver extends ContentObserver {

        SettingsContentObserver(Handler handler) {
            super(handler);
        }

        @Override
        public boolean deliverSelfNotifications() {
            return super.deliverSelfNotifications();
        }

        @Override
        public void onChange(boolean selfChange) {
            super.onChange(selfChange);
            volumeDialogContract.updateMediaVolume(getMediaVolume());


    }

    int getMediaVolume() {
        return audioManager.getStreamVolume(AudioManager.STREAM_MUSIC);
    }



    void unRegisterVolumeChangeListener() {
        volumeDialogContract.getAppContext().getApplicationContext().getContentResolver().
                unregisterContentObserver(settingsContentObserver);
    }

    void registerVolumeChangeListener() {
        settingsContentObserver = new VolumeDialogPresenter.SettingsContentObserver(new Handler());
        volumeDialogContract.getAppContext().getApplicationContext().getContentResolver().registerContentObserver(
                android.provider.Settings.System.CONTENT_URI, true,
                settingsContentObserver);
    }

是否有针对音量变化的广播动作？

9 个答案: