android - MediaButtonReceiver 不适用于 MediaBrowserServiceCompat

Question

我正在尝试从耳机或汽车控件(播放/暂停/等)接收媒体按钮事件

这在我的应用程序 list 中。

<service android:name=".mediaPlayerService.MediaPlayerService"
         android:exported="true">
    <intent-filter>
        <action android:name="android.media.browse.MediaBrowserService"/>
    </intent-filter>
</service>

<!--
A receiver that will receive media buttons and send as
intents to your MediaBrowserServiceCompat implementation.
Required on pre-Lollipop. More information at
http://developer.android.com/reference/android/support/v4/media/session/MediaButtonReceiver.html
-->
<receiver android:name="android.support.v4.media.session.MediaButtonReceiver">
    <intent-filter>
        <action android:name="android.intent.action.MEDIA_BUTTON"/>
    </intent-filter>
</receiver>

这是我的 MediaPlayerService 的一部分

public class MediaPlayerService extends MediaBrowserServiceCompat {

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

private void initMediaSessions()
{
    mSession = new MediaSessionCompat(getApplicationContext(), MediaPlayerService.class.getSimpleName());
    setSessionToken(mSession.getSessionToken());

    mSession.setCallback(new MediaSessionCompat.Callback()
                         {
                            //callback code is here.     
                         }            
    );
}

@Override
public int onStartCommand(Intent startIntent, int flags, int startId)
{
    if (startIntent != null)
    {
        // Try to handle the intent as a media button event wrapped by MediaButtonReceiver
        MediaButtonReceiver.handleIntent(mSession, startIntent);
    }
    return START_STICKY;
}

我好像漏掉了什么。当我按下耳机控件上的暂停按钮时，永远不会调用 onStartCommand。

知道为什么这没有按预期工作吗？

Answer 1

如 Best Practices in media playback I/O 2016 talk 中所述, 你还需要调用

mSession.setFlags(
  MediaSessionCompat.FLAG_HANDLES_MEDIA_BUTTONS |
  MediaSessionCompat.FLAG_HANDLES_TRANSPORT_CONTROLS);

构建媒体 session 时和开始播放之前，必须调用 setActive(true)根据其文档:

You must set the session to active before it can start receiving media button events or transport commands.

请注意，您还必须 call setActions()在你的 PlaybackStateCompat.Builder准确说明您支持的操作 - 如果您不设置它，那么您将不会收到任何与媒体按钮相关的回调。