MediaRouter.sendControlRequest不起作用

Question

我正在开发小型android chromecast发件人应用程序。当我试图使用MediaRouter API创建新会话时，它不起作用。

import android.support.v7.media.MediaControlIntent;
import android.support.v7.media.MediaRouteSelector;
import android.support.v7.media.MediaRouter;

class PlayerFragment extends Fragment 
{

MediaRoute.Callback cb;

/*
  ....
*/


cb = new MediaRouter.Callback() {
        @Override
        public void onRouteSelected(MediaRouter router, MediaRouter.RouteInfo route) {
            super.onRouteSelected(router, route);

            Log.v("PlayerFragment", "Route selected");
            mRoute = route;
            createSession();
        }

        @Override
        public void onRouteUnselected(MediaRouter router, MediaRouter.RouteInfo route) {
            super.onRouteUnselected(router, route);

            mRoute = null;
        }
    };

private void startDiscovery(){
    mRouter.addCallback(selector, cb, MediaRouter.CALLBACK_FLAG_REQUEST_DISCOVERY);
}

private void createSession(){

    Intent intent = new Intent(MediaControlIntent.ACTION_START_SESSION);

    intent.addCategory(MediaControlIntent.CATEGORY_REMOTE_PLAYBACK);

    intent.putExtra(CastMediaControlIntent.EXTRA_CAST_APPLICATION_ID,
            CastMediaControlIntent.DEFAULT_MEDIA_RECEIVER_APPLICATION_ID);

    intent.putExtra(CastMediaControlIntent.EXTRA_CAST_RELAUNCH_APPLICATION, true);

    intent.putExtra(CastMediaControlIntent.EXTRA_DEBUG_LOGGING_ENABLED, true);

    intent.putExtra(CastMediaControlIntent.EXTRA_CAST_STOP_APPLICATION_WHEN_SESSION_ENDS,
            true);

    mRoute.sendControlRequest(intent, new MediaRouter.ControlRequestCallback() {
        @Override
        public void onResult(Bundle data) {
            super.onResult(data);

            mSessionId = data.getString(MediaControlIntent.EXTRA_SESSION_ID);
            Log.v("PlayerFragment", "Session ID is: " + mSessionId);
        }
    });
}

}

应用程序不在电视上启动，logcat中没有对应的字符串，onResult方法中的调试器断点也没有捕获。这里是logcat的一部分

10-05 23:02:05.097    5740-5740/shirokovoi.ChromeCastSSAPP I/System.out﹕ debugger has settled (1372)
10-05 23:02:05.582    5740-5740/shirokovoi.ChromeCastSSAPP I/MediaRouter﹕ Found default route: MediaRouter.RouteInfo{ uniqueId=android/.support.v7.media.SystemMediaRouteProvider:DEFAULT_ROUTE, name=Tablet, description=null, enabled=true, connecting=false, playbackType=0, playbackStream=3, volumeHandling=1, volume=15, volumeMax=15, presentationDisplayId=-1, extras=null, providerPackageName=android }
10-05 23:02:06.074    5740-5740/shirokovoi.ChromeCastSSAPP D/android.widget.GridLayout﹕ vertical constraints: y1-y0>=500, y2-y1>=32, y3-y2>=48, y4-y3>=0, y4-y0<=512 are inconsistent; permanently removing: y4-y0<=512.
10-05 23:02:06.222    5740-5740/shirokovoi.ChromeCastSSAPP D/OpenGLRenderer﹕ Enabling debug mode 0
10-05 23:02:06.722    5740-5740/shirokovoi.ChromeCastSSAPP I/Timeline﹕ Timeline: Activity_idle id: android.os.BinderProxy@419a2a68 time:38947645
10-05 23:02:15.863    5740-5740/shirokovoi.ChromeCastSSAPP V/PlayerFragment﹕ Route selected

Answer 1

最后，我解决了这个问题。重点是在我的意图中缺少EXTRA_SESSION_STATUS_UPDATE_RECEIVER。我不知道为什么没有这个额外的，但如果我加起来，它是有效的。