Build fragment backStack for push notification

Question

I am using FCM to show a fragment when user tap on the notification from the status bar.

Current app flow is this MainActivity (Fragment A -> Fragment B -> Fragment C).

However when user tap a notification (whether app is running or not), I want to show Fragment C while still providing a proper back navigation so on back key press, user is taken to Fragment B and Fragment A when pressed again.

I know activities have TaskStackBuilder for such purpose but I couldn't find anything for building backStack for fragments before showing my notification.

Any idea how I could build a stack? I tried adding all fragments into the transaction then commit before adding Fragment C but I get IllegalStateException: commit already called while on the second commit

Answer 1

Manual handling of fragment stack is hard. I would recommend you checking out Navigation Component . It will allow to build explicit deep links with proper back stack handling ( NavDeepLinkBuilder class).

Show your code. Probably you have to create new transaction for every fragment and commit operation. Use this method to add A, B and C:

    public void addFragmentOnTop(Fragment fragment) {
        getSupportFragmentManager()
            .beginTransaction()
            .replace(R.id.container, fragment)
            .addToBackStack(null)
            .commit();
    }