背景信息：每当用户按下大多数耳机上的播放/暂停按钮时,我都需要检测(KEYCODE_MEDIA_PLAY_PAUSE).
我拥有它主要使用MediaSessions,但当另一个应用程序开始播放音频时,我停止回调.
这似乎是因为正在播放音频的应用创建了自己的MediaSession,而Android仅将KeyEvents发送到最新的MediaSession.为了防止这种情况,我创建一个OnActiveSessionsChangedListener并在每次触发时创建一个新的MediaSession.
这确实有效,但每次我创建一个新的MediaSession时,监听器再次触发,所以我发现自己陷入了一个inf循环.
我的问题：有谁知道我怎么做以下任何一个??：
>防止其他应用程序窃取我的媒体按钮焦点
>检测我何时将媒体按钮焦点丢失到另一个应用程序,这样我就可以创建一个新的MediaSession,而不是每当有效时
会议变了
>检查我当前是否已经有媒体按钮焦点,所以我不必要地创建一个新的MediaSession
什么行不通：
> BroadcastReceiver on
AudioEffect.ACTION_OPEN_AUdio_EFFECT_CONTROL_SESSION不起作用
因为应用必须手动触发广播和许多应用,
像NPR一样不
> AudioManager.OnAudioFocusChangeListener无法正常工作,因为它需要我
音频焦点
>在android.intent.action.MEDIA_BUTTON&上具有最高优先级的BroadcastReceiver调用abortBroadcast(),但当其他应用程序播放音频时,我的接收器未被触发.此外,其他应用程序也可以设置最高优先级.
我的代码：
mMediaSessionManager.addOnActiveSessionsChangedListener(controllers -> {
boolean updateButtonReceiver = false;
// recreate MediaSession if another app handles media buttons
for (MediaController mediaController : controllers) {
if (!TextUtils.equals(getPackageName(),mediaController.getPackageName())) {
if ((mediaController.getFlags() & (MediaSessionCompat.FLAG_HANDLES_MEDIA_BUTTONS | MediaSessionCompat.FLAG_HANDLES_TRANSPORT_CONTROLS)) != 0L) {
updateButtonReceiver = true;
}
}
}
if (updateButtonReceiver) {
// using a handler with a delay of about 2 seconds because this listener fires very often.
mAudioFocusHandler.removeCallbacksAndMessages(null);
mAudioFocusHandler.sendEmptyMessageDelayed(0,AUdio_FOCUS_DELAY_MS);
}
},ClickAppNotificationListener.getComponentName(this));
这是被触发的处理程序：
private final Handler mAudioFocusHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
if (mShouldBeEnabled) {
updateButtonReceiverEnabled(true);
}
}
};
最后,这是Handler触发的方法：
private void updateButtonReceiverEnabled(boolean shouldBeEnabled) {
// clear old session (not sure if this is necessary)
if (mMediaSession != null) {
mMediaSession.setActive(false);
mMediaSession.setFlags(0);
mMediaSession.setCallback(null);
mMediaSession.release();
mMediaSession = null;
}
mMediaSession = new MediaSessionCompat(this,MEDIA_SESSION_TAG);
mMediaSession.setCallback(mMediaButtonCallback);
mMediaSession.setFlags(MediaSessionCompat.FLAG_HANDLES_MEDIA_BUTTONS | MediaSessionCompat.FLAG_HANDLES_TRANSPORT_CONTROLS);
mMediaSession.setPlaybackToLocal(AudioManager.STREAM_MUSIC);
mMediaSession.setActive(true);
mMediaSession.setPlaybackState(new PlaybackStateCompat.Builder()
.setActions(PlaybackStateCompat.ACTION_PLAY_PAUSE)
.setState(PlaybackStateCompat.STATE_CONNECTING,0f)
.build());
if (shouldBeEnabled != mShouldBeEnabled) {
getPackageManager().setComponentEnabledSetting(mMediaButtonComponent,shouldBeEnabled
? PackageManager.COMPONENT_ENABLED_STATE_ENABLED
: PackageManager.COMPONENT_ENABLED_STATE_DISABLED,PackageManager.DONT_KILL_APP);
}
mShouldBeEnabled = shouldBeEnabled;
}
谢谢！
MediaButtonIntentReceiver类：
public class MediaButtonIntentReceiver extends BroadcastReceiver {
public MediaButtonIntentReceiver() {
super();
}
@Override
public void onReceive(Context context,Intent intent) {
String intentAction = intent.getAction();
if (!Intent.ACTION_MEDIA_BUTTON.equals(intentAction)) {
return;
}
KeyEvent event = (KeyEvent)intent.getParcelableExtra(Intent.EXTRA_KEY_EVENT);
if (event == null) {
return;
}
int action = event.getAction();
if (action == KeyEvent.ACTION_DOWN) {
// do something
Toast.makeText(context,"BUTTON PRESSED!",Toast.LENGTH_SHORT).show();
}
abortBroadcast();
}
}
将其添加到manifest.xml：
并像这样注册你的BroadcastReceiver(在主要活动中)
IntentFilter filter = new IntentFilter(Intent.ACTION_MEDIA_BUTTON);
MediaButtonIntentReceiver r = new MediaButtonIntentReceiver();
filter.setPriority(1000);
registerReceiver(r,filter);
还看看：
How to capture key events from bluetooth headset with android
How do I intercept button presses on the headset in Android?
