有人可以帮助我使用 Android RemoteControlClient 吗？

我正在尝试获取RemoteControlClient设置以便我的应用程序的音乐可以通过锁定屏幕上弹出的小部件进行控制（例如 SoundCloud、Google Play 音乐和其他音乐/视频应用程序）。我不确定我的代码有什么问题以及为什么它没有正确挂钩，但这是我到目前为止所拥有的......

一个名为 MusicService 的类尝试处理 RemoteControlClient 的更新

public class MusicService extends Service
{
public static final String ACTION_PLAY = "com.stfi.music.action.PLAY";
private RemoteController controller = null;

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

    System.out.println("Creating the service.");

    if(controller == null)
    {
        controller = new RemoteController();
    }
}

@Override
public int onStartCommand(Intent intent, int flags, int startId)
{
    String action = intent.getAction();
    System.out.println("Got an action of " + action);

           /* Logic to get my Song cur */
    controller.register(this);
    controller.updateMetaData(cur);

    return START_STICKY;
}

@Override
public void onDestroy()
{
    super.onDestroy();
    System.out.println("Destorying MusicService");
}

@Override
public IBinder onBind(Intent intent) {
    // TODO Auto-generated method stub
    return null;
}
}

这使用了我调用的一个类RemoteController其中容纳了我的RemoteControlClient.

public class RemoteController { 
private RemoteControlClient remoteControlClient;
private Bitmap dummyAlbumArt;


public void register(Context context)
{
    if (remoteControlClient == null)
    {
        System.out.println("Trying to register it.");

        dummyAlbumArt = BitmapFactory.decodeResource(context.getResources(), R.drawable.dummy_album_art);

        AudioManager audioManager = (AudioManager) context.getSystemService(context.AUDIO_SERVICE);

        ComponentName myEventReceiver = new ComponentName(context.getPackageName(), MediaButtonReceiver.class.getName());
        audioManager.registerMediaButtonEventReceiver(myEventReceiver);

        // build the PendingIntent for the remote control client 
        Intent mediaButtonIntent = new Intent(Intent.ACTION_MEDIA_BUTTON);
        mediaButtonIntent.setComponent(myEventReceiver);
        // create and register the remote control client 
        PendingIntent mediaPendingIntent = PendingIntent.getBroadcast(context, 0, mediaButtonIntent, 0);
        remoteControlClient = new RemoteControlClient(mediaPendingIntent);
        remoteControlClient.setTransportControlFlags(RemoteControlClient.FLAG_KEY_MEDIA_PLAY_PAUSE
                | RemoteControlClient.FLAG_KEY_MEDIA_NEXT
                | RemoteControlClient.FLAG_KEY_MEDIA_PREVIOUS
                | RemoteControlClient.FLAG_KEY_MEDIA_PLAY
                | RemoteControlClient.FLAG_KEY_MEDIA_PAUSE
                );
        audioManager.registerRemoteControlClient(remoteControlClient);


    }
} 

/** 
 * Update the state of the remote control. 
 */ 
public void updateState(boolean isPlaying)
{
    if(remoteControlClient != null)
    {
        if (isPlaying)
        {
            remoteControlClient.setPlaybackState(RemoteControlClient.PLAYSTATE_PLAYING);
        }

        else
        { 
            remoteControlClient.setPlaybackState(RemoteControlClient.PLAYSTATE_PAUSED);
        } 
    } 
} 

/** 
 * Updates the state of the remote control to "stopped". 
 */ 
public void stop()
{ 
    if (remoteControlClient != null)
    {
        remoteControlClient.setPlaybackState(RemoteControlClient.PLAYSTATE_STOPPED);
    } 
} 

public void updateMetaData(Song song)
{
    if (remoteControlClient != null && song != null)
    {
        System.out.println("Updating metadata");
        MetadataEditor editor = remoteControlClient.editMetadata(true);
        editor.putBitmap(MetadataEditor.BITMAP_KEY_ARTWORK, dummyAlbumArt);
        editor.putLong(MediaMetadataRetriever.METADATA_KEY_DURATION, (long)1000);
        editor.putString(MediaMetadataRetriever.METADATA_KEY_ARTIST, "Artist");
        editor.putString(MediaMetadataRetriever.METADATA_KEY_TITLE, "Title");
        editor.apply();

        updateState(true);
    }
}

/** 
 * Release the remote control. 
 */ 
public void release() { 
    remoteControlClient = null;
} 
} 

每次我想更新小部件时，我都会调用startService(new Intent(MusicService.ACTION_PLAY));。看起来它正确地创建了服务，并且总是到达“更新元数据”的位置，但由于某种原因，当我锁定屏幕并解锁它时，我在锁定屏幕上看不到任何小部件。

以下也是我的清单的重要部分，因为这可能会以某种方式导致问题......

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.stfi"
android:versionCode="1"
android:versionName="1.0" >

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WAKE_LOCK" />

<uses-sdk
    android:minSdkVersion="14"
    android:targetSdkVersion="17" />

<application
    android:hardwareAccelerated="true"
    android:allowBackup="true"
    android:icon="@drawable/stfi"
    android:label="@string/app_name"
    android:largeHeap="true"
    android:theme="@style/MyActionBarTheme" >
    <meta-data
        android:name="android.app.default_searchable"
        android:value=".activities.SearchActivity" />

    <activity
        android:name=".StartingToFeelIt"
        android:configChanges="orientation|keyboardHidden"
        android:label="@string/app_name"
        android:screenOrientation="portrait" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>

        <meta-data
            android:name="android.app.searchable"
            android:resource="@xml/searchable" />
    </activity>
    ...other activities listed

    <service
        android:name=".helpers.MyNotificationService"
        android:enabled="true"
        android:label="MyNotificationServiceLabel" >
    </service>
    <service
        android:name=".music.MusicService"
        android:exported="false" >
        <intent-filter>

            <action android:name="com.stfi.music.action.PLAY" />

        </intent-filter>
        <intent-filter>
            <action android:name="com.example.android.musicplayer.action.URL" />

            <data android:scheme="http" />
        </intent-filter>
    </service>

    <receiver
        android:name=".music.MediaButtonReceiver"
        android:exported="false" >
    </receiver>
</application>

现在我的 MediaButtonReceiver 并没有真正做任何事情。我只是想把钩子设置好。如果你愿意，这是我的 MediaButtonReceiver 类......

public class MediaButtonReceiver extends BroadcastReceiver
{
@Override
public void onReceive(Context context, Intent intent)
{
    System.out.println("Receiving something.");
    if (intent.getAction().equals(Intent.ACTION_MEDIA_BUTTON))
    {
        final KeyEvent event = (KeyEvent) intent.getParcelableExtra(Intent.EXTRA_KEY_EVENT);

        if (event != null && event.getAction() == KeyEvent.ACTION_UP)
        {

            if (event.getKeyCode() == KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE)
            {
                System.out.println("You clicked pause.");
            }

            else if(event.getKeyCode() == KeyEvent.KEYCODE_MEDIA_PLAY)
            {
                System.out.println("You clicked play.");
            }

            else if (event.getKeyCode() == KeyEvent.KEYCODE_MEDIA_NEXT)
            {
                System.out.println("You clicked next.");
            }

            else if (event.getKeyCode() == KeyEvent.KEYCODE_MEDIA_PREVIOUS)
            {
                System.out.println("You clicked previous.");
            }
        }
    }
}

}

如果您在锁定屏幕上看不到 RemoteControlClient，则必须实现音频焦点。你可以看here http://developer.android.com/training/managing-audio/audio-focus.html