FragmentonBackPress Demo

If you’ve been an Android developer, you have handled back-press events using the onBackPressed() function in activities. That was fine until the introduction of architectural components and a single source of truth patterns. Now we have onBackPressedDispatcher so use this in fragments and we can handle the back-press for fragments with in the fragments.

In this Repo we have achieved the same using onBackPressedDispatcher and OnBackPressedCallback.

We just need to add the block of code in your fragments and rest will be done.

    requireActivity().onBackPressedDispatcher.addCallback(this,object : OnBackPressedCallback(true){
            override fun handleOnBackPressed() {
                if(you have any specific conditions){
                // handle back-press in fragments
                }else{
                  isEnabled = false. // this will disable the onBackPressedDispatcher callback
                  activity?.onBackPressed() // called activity onBackPressed()
                }
            }
        })

Unregistered the onBackPressedDispatcher in fragments onDestroyView()

override fun onDestroyView() {
    super.onDestroyView()
    //unregister listener here
    onBackPressedCallback.isEnabled = false
    onBackPressedCallback.remove()
}

I am facing issues , when i tried to implement the same in my ongoing project and its not received call in handleOnBackPressed() or OnBackPressedCallback() is not called so i have gone through project code and struture after checking codes, foung that onBackPressed() in Activity must not be do some stuff related to fragment.

As i have written some code in my Activit's onBackPressed() posted below.

      @Override
  public void onBackPressed() {
      Log.e("Here We are","in BlinkIDScanBaseActivity");
      Intent intent = new Intent();
      setResult(RESULT_CANCELED, intent);
      finish();
  }

just commented the code and all works fine , Its my observation , will read about it and post here.
Same happen another Activity.
Finally fixed my proble after removing the code from Activity's onBackPressed()

References

AmandeepTomar/FragmentonBackPress

FragmentonBackPress Demo