Android Cast - 媒体路由器回调未返回

Question

我正在尝试自动发现Cast设备。这基本上是我已经看到的如何执行此操作，但是我从来没有获得onRouteAdded或onRouteSelected的回调。

我已经尝试更改使用哪些标志，但没有得到不同的结果。有时会添加路线，但从未选择。

private void startSearchForDevicesAndCast() {
    MediaRouter router = MediaRouter.getInstance(this);

    int count = router.getRoutes().size();

    List<MediaRouter.RouteInfo> j = router.getRoutes();
    MediaRouteSelector selector = new MediaRouteSelector.Builder().addControlCategory(
            CastMediaControlIntent.categoryForCast(getString(R.string.app_id))).build();

    router.addCallback(selector, new MediaRouter.Callback() {
        @Override
        public void onRouteAdded(MediaRouter router, MediaRouter.RouteInfo route) {
            super.onRouteAdded(router, route);
            Log.i(TAG, "onRouteAdded: ");
            router.selectRoute(route);
        }

        @Override
        public void onRouteChanged(MediaRouter router, MediaRouter.RouteInfo route) {
            super.onRouteChanged(router, route);
            Log.i(TAG, "onRouteChanged: ");
        }

        @Override
        public void onRouteSelected(MediaRouter router, MediaRouter.RouteInfo route) {
            Log.i(TAG, "onRouteSelected: ");
            super.onRouteSelected(router, route);
        }
    }, MediaRouter.CALLBACK_FLAG_PERFORM_ACTIVE_SCAN);
}