Ignoring navigate() call: FragmentManager has already saved its state

问题

I'm using navigation in MainActivity, then I start SecondActivity (for result). After finish of SecondActivity I would like to continue with navigation in MainActivity, but FragmentManager has saved his state already.

On Navigation.findNavController(view).navigate(R.id.action_next, bundle) I receive log message:

Ignoring navigate() call: FragmentManager has already saved its state

How I can continue in navigation?

回答1:

You must always call super.onActivityResult() in your Activity's onActivityResult. That is what:

1. Unlocks Fragments so they can do fragment transactions (i.e., avoid the state is already saved errors)

2. Dispatches onActivityResult callbacks to Fragments that called startActivityForResult.

回答2:

Finally, I fix the issue by simple calling super.onPostResume() right before navigating to restore state.

回答3:

I've solved this problem this way:

    @Override
public void onActivityResult() { //inside my fragment that started activity for result
        model.navigateToResults = true; //set flag, that navigation should be performed
}

and then

    @Override
public void onResume() { //inside fragment that started activity for result
    super.onResume();

    if(model.navigateToResults){
        model.navigateToResults = false;
        navController.navigate(R.id.action_startFragment_to_resultsFragment);
    }
}

not sure, if this is not a terrible hack, but it worked for me. FramgentManager state is restored at this point (onResume) and no problems with navigation occur.

来源：https://stackoverflow.com/questions/51895243/ignoring-navigate-call-fragmentmanager-has-already-saved-its-state