Android Tip : Handling back button in Fragments

This post explains how to handle hardware back button in a Fragment OR DialogFragment.

In DialogFragment, it’s quiet straight forward to achieve this. You’ve to get the dialog instance and set onKeyListener on it :

if (getDialog() != null) {
            getDialog().setOnKeyListener(new DialogInterface.OnKeyListener() {
                @Override
                public boolean onKey(DialogInterface dialog, int keyCode, KeyEvent event) {
                    if (event.getAction() == KeyEvent.ACTION_UP && keyCode == KeyEvent.KEYCODE_BACK) {
                        Timber.i("hardware back button pressed");
                    }
                }
            });
        }

This can be done in the onViewCreated callback.

For fragments, this method doesn’t work and fragments doesn’t have a direct callback to catch this event. So in this case, the approach that we follow is :
You have to catch this event in activity’s onBackPressed method and then call a method on your fragment that handles this, something like :

@Override
public void onBackPressed() {
    Fragment fragment = getSupportFragmentManager().findFragmentByTag(tagWithWhichYouAddedIt);
    if (fragment.handlebackPress()) { // and then you define a method handlebackPress with the logic to handle back press or not
        // decide how you want to proceed
    }
}

Note that you’ll find some references on internet which ask you to set KeyListener on fragment’s parent view, but that doesn’t work.


Let me know in case of any doubts.


Cheers !