如何使用onBackPressed（）在片段上显示AlertDialog？

Question

I use DrawerNavigation to manage different fragments in the program and also override onBackPressed in the main activity to use the onBackPressed in fragment as this post: https://medium.com/@Wingnut/onbackpressed-for-fragments-357b2bf1ce8e

Thanks to Daniel Wilson that I can use onBackPressed in Fragment but when I want to display the alert when the user pressed back button after modifying an EditText without saving. The current fragment is just popped back to the previous one and the alert display on the other fragment. How would I change it - Displaying the alert dialog on the dialog call?

The following is my code

MyDialogFragment

public static class MyDialogFragment extends DialogFragment {

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        AlertDialog alertDialog;
        alertDialog = new AlertDialog.Builder(getActivity())
                .setMessage(R.string.unsaved_changes_dialog_msg)
                .setPositiveButton(R.string.discard,
                        new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int whichButton) {

                                myContext.getSupportFragmentManager().popBackStack();
                            }
                        }
                )
                .setNegativeButton(R.string.keep_editing, new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int id) {
                        // User clicked the "Keep editing" button, so dismiss the dialog
                        // and continue editing the pet.
                        if (dialog != null) {
                            dialog.dismiss();
                        }
                    }
                })
                .create();

        return alertDialog;
    }

}

onBackPressed

@Override
public void onBackPressed() {
    if (!mPetHasChanged) {
        Log.i(TAG, "onBackPressed: + mPetHasNotChanged");
        super.onBackPressed();
        return;
    }

    FragmentManager fm = getFragmentManager();
    MyDialogFragment dialogFragment = new MyDialogFragment ();
    dialogFragment.show(fm, "Sample Fragment");

    Log.i(TAG, "onBackPressed: ");
}

Thank you everyone,

Answer 1

Try this

@Override
public void onBackPressed() {

      FragmentManager fm = getFragmentManager();
      MyDialogFragment dialogFragment = new MyDialogFragment ();
      dialogFragment.show(fm, "Sample Fragment");

    super.onBackPressed();
    return;
   }

}

Answer 2

There is no onBackPressed() method for in Fragment, so we create CallBackInterface and use OnBackPressed() of activity. Follow this link : http://vinsol.com/blog/2014/10/01/handling-back-button-press-inside-fragments/ hope It will help you.

Answer 3

You can use OnBackPressed() of activity, when it calls, show your dialog. Add Listener on dismiss (use custom listener IMHO). Dependence on the choice proceed your code.
It's like @mehul says, just add a listener mechanism.