How to fix OnBackPressedCallback if it doesn't work in Fragment?

Question

Here I override handleOnBackPressed() method:

 Log.d("Fragment", "onViewCreated")
        requireActivity().onBackPressedDispatcher.addCallback(viewLifecycleOwner) {
            object : OnBackPressedCallback(true) {
                override fun handleOnBackPressed() {
                    Log.d("Fragment", "Back pressed")
                    if (binding.crimeTitle.text.isBlank()) {
                        Toast.makeText(context, "Title can't be empty!", Toast.LENGTH_SHORT).show()
                        Log.d("Fragment", "Toast showed")
                    } else {
                        Log.d("Fragment", "BackStack popped")
                        findNavController().popBackStack()
                    }
                }
            }
        }

But after that I see only "onViewCreated" in Logs and nothing happens after pressing "Back" button.
I expected to see at least "Back pressed".
Witout this part of code "Back" button works as usual.
Logs:
(https://i.stack.imgur.com/bAmxq.png)

You might have implemented OnBackPressed in your activity. – SURYA S R Jan 18 '23 at 15:03 — SURYA S R, Jan 18 '23 at 15:03

score 1 · Answer 1 · answered Jan 19 '23 at 09:40

Finally, I've found a solution.
It's important to add that callback in "onCreate" function of Fragment, otherwise "Back" button won't react on your actions. And owner in "addCallback(owner)" have to be "this", If you try to pass "viewLifecycleOwner" you'll get an exception:

FATAL EXCEPTION: main
java.lang.IllegalStateException: Can't access the Fragment View's LifecycleOwner when getView() is null i.e., before onCreateView() or after onDestroyView()

How to fix OnBackPressedCallback if it doesn't work in Fragment?

1 Answers1