What is the proper way to handle a screen rotation and the media route button and the existing session? - google-cast

Question

The example on https://developers.google.com/cast/cast_2nd-screen_app_tutorial shows a onDestroy method which calls unregisterMediaRouteProvider. This causes the MediaRouter.Callback.onRouteUnselected method to get called which in turn ends the session. This leads to the app getting disconnected from the chromecast device and the MediaRouteButton stops being blue. Below is the onDestroy method from the example:
#Override
protected void onDestroy() {
MediaRouteHelper.unregisterMediaRouteProvider(mCastContext);
mCastContext.dispose();
super.onDestroy();
}
So my question is, what is the proper way to handle screen rotation when using the chromecast device from an app?

Answer 1

You can try using isFinishing() method of Activity to figure out if onDestroy is called due to application really "finishing" or is called for other reasons. Another option is to handle orientation change yourself.

Answer 2

You can see the guidelines for handling setup/destruction of the Chromecast (such as when orientation change is happening) on https://developers.google.com/cast/docs/android_sender
The relevant sections of code are the following ones:
#Override
protected void onResume() {
super.onResume();
mMediaRouter.addCallback(mMediaRouteSelector, mMediaRouterCallback,
MediaRouter.CALLBACK_FLAG_REQUEST_DISCOVERY);
}
#Override
protected void onPause() {
if (isFinishing()) {
mMediaRouter.removeCallback(mMediaRouterCallback);
}
super.onPause();
}
And also the following code:
#Override
protected void onStart() {
super.onStart();
mMediaRouter.addCallback(mMediaRouteSelector, mMediaRouterCallback,
MediaRouter.CALLBACK_FLAG_REQUEST_DISCOVERY);
}
#Override
protected void onStop() {
mMediaRouter.removeCallback(mMediaRouterCallback);
super.onStop();
}
It is also a good idea to have a boolean value in your program, for instance "wasLaunched" or "isConnected" to keep track of whether the connection to the chromecast is active or not. I use this variable in my code to check if I can send messages to the receiver or not. Then simply remember to save this variable and restore it when there is an orientation change on the device. This works for me in my chromecast enabled app. The code for saving/restoring my variable, so it survices orientation change is shown below:
protected void onSaveInstanceState(Bundle bundle) {
if (bundle!=null)
{
bundle.putBoolean("wasLaunched", wasLaunched);
}
super.onSaveInstanceState(bundle);
}
protected void onRestoreInstanceState(Bundle savedInstanceState) {
if (savedInstanceState!=null)
{
wasLaunched = savedInstanceState.getBoolean("wasLaunched");
}
super.onRestoreInstanceState(savedInstanceState);
};
Of course you can also put other stuff in your bundle that needs to survive an orientation change. I am not using the onDestroy override you describe there, nor is it mentioned in the google documentation I link to. But I use the teardown() method described in that document I link to for cleaning up, but this only happens when I close the connection, because I dont want to close the connection to the chromecast upon orientation change.