I'm writing android app, using fragments.

There are two main ways to navigate up or back.

picture of the screen

1. The first is to use the arrow on the navigation bar (marked with the number 1 in the picture)

2. The second use the system back button (marked with the number 2)

I wrote:

override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View {
...
        requireActivity().onBackPressedDispatcher.addCallback(this) {
                findNavController().navigate(R.id.action_updateFragment_to_listFragment)
...    
}

and it works just fine, but only for system back button(2).

How can I override action caused by click on the back arrow from navigation bar(1)?

thanks!!!

CodePudding user response：

Ok, I've got this.

override fun onOptionsItemSelected(item: MenuItem): Boolean {
        if(item.itemId == android.R.id.home) {
            Toast.makeText(requireContext(), "the answer", Toast.LENGTH_SHORT).show()
        }
        return super.onOptionsItemSelected(item)
    }

I hope this post will help someone in the future.