How to show warning message when back button is pressed in fragments

Question

I want application to show warning message when user press back button and if user select Yes it will go back. And i am in navigation graph fragment.

I have searched many time in stack Overflow and tried:

@Override
public void onBackPressed() {
    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());

    builder.setTitle("Save Or Not");
    builder.setMessage("Do you want to save this? ");
    builder.setPositiveButton("Save", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int id) {
            /*Go back:-I dont know how*/
        }
    });
    builder.setNegativeButton("Discard",null);
    builder.show();
}

But it is showing giver error: Method does not override method from its superclass

Edit: I want to set onBackPressedListener(Mobiles back button) in Navigation graphs fragment

Add boolean variable isBack = false and if it say yes make it true and check the condition that isBack is false or true and if it is true add super.pressBack() else show the alter dialog wrap the alter dialog in different function — Jainil Patel, May 27 '19 at 04:46
I need to onBackButtonClickListener- In Navigation graph fragment — Aradhya Gopal Nepal, May 27 '19 at 05:16

score 4 · Accepted Answer · answered May 27 '19 at 06:08

When using Fragments 1.1.0 (which is in alpha right now), you can follow the Provide custom back navigation documentation, which shows how to register an OnBackPressedCallback, which allows you to register for onBackPressed() callbacks from within a Fragment:

public class MyFragment extends Fragment {

  @Override
  public void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    // This callback will only be called when MyFragment is at least Started.
    OnBackPressedCallback callback = new OnBackPressedCallback(true /* enabled by default */) {
        @Override
        public void handleOnBackPressed() {
            AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());

            builder.setTitle("Save Or Not");
            builder.setMessage("Do you want to save this? ");
            builder.setPositiveButton("Save", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                // Save your content
                save();
                // Then pop
                NavHostFragment.findNavController(MyFragment.this).popBackStack();
            }
            builder.setNegativeButton("Discard",null);
            builder.show();
        });
        }
    });
    requireActivity().getOnBackPressedDispatcher().addCallback(this, callback);
  }
}

I have version 1.0.0-beta02 fragment version in gradel. Can changing it from gradel to 1.1.0 update its version — Aradhya Gopal Nepal, May 27 '19 at 07:33
Note the "requireActivity()" prefix above is needed when the OnBackPressedDispatcher is set up from within a Fragment but the prefix is not needed when setting up from within an Activity. — AJW, Sep 11 '19 at 01:58

Nikunj Paradva · Answer 2 · 2019-05-27T05:24:46.477

3

Add this line in button clicklistner MainActivity.super.onBackPressed(); Replace your Activity name insted of MainActivity

 builder.setPositiveButton("Save", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int id) {
          dialog.dismiss();
          MainActivity.super.onBackPressed();
         //Replace your Activity name insted of MainActivity
        }
    });

edited May 27 '19 at 05:24

answered May 27 '19 at 04:49

Nikunj Paradva

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Thanks for help but i am in android navigation graph fragment and when i type CreateGame.super.onBackPressed(); it cannot resolve it(i have also done getActivity()) – Aradhya Gopal Nepal May 27 '19 at 05:20
Android studio is not resolving .onBackPressed() in extends fragment – Aradhya Gopal Nepal May 27 '19 at 05:24
onbackpress is only for Activity not in Fragment , use onbackpress for that Fragment in their parent Activity – Nikunj Paradva May 27 '19 at 05:25
oh sad to hear that. Thanks for help – Aradhya Gopal Nepal May 27 '19 at 05:31

score 1 · Answer 3 · answered May 27 '19 at 04:53

builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                   //Replace Your Own Action Like Adding Toast etc and Also SuperOnbackprssed or any overriden method
                    dialog.cancel();

                }
            });

How to show warning message when back button is pressed in fragments

3 Answers3

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