DialogFragment Interface that Can Be Implemented in Activities and Fragments
<p>I have a <code>ListFragment</code> with a context menu for my <code>ListItem</code>s. One of the menu options is for deleting the item, and I want to show a confirmation dialog to the user to prevent accidental deletes. </p>

<pre><code>public class MyListFragment extends ListFragment implements ConfirmDeletePopupFragment.DialogListener {

    (...)

    @Override
    public boolean onContextItemSelected(MenuItem item) {

        switch (item.getItemId()) {
            case R.id.action_delete:
                ConfirmDeletePopupFragment fragment = new ConfirmDeletePopupFragment();
                fragment.show(getSupportFragmentManager(), "tag");
                return true;
            case R.id.action_cancel:
                return true;
            default:
                return super.onContextItemSelected(item);
        }
    }

}
</code></pre>

<p>For a similar situation, I have created a generic confirmation dialog as a <code>DialogFragment</code> as shown below. This I can use to let the user confirm any critical actions. For use in an <code>Activity</code> it has an Interface with a method <code>onDeleteConfirm</code> that handles the actual deletion in the <code>Activity</code> which created the dialog.</p>

<pre><code>public class ConfirmDeletePopupFragment extends DialogFragment {

    (...)

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        try {
            mDialogListener = (DialogListener) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(getTargetFragment().toString() + " must implement ConfirmDeletePopupFragment.DialogListener");
        }
    }

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        final android.app.AlertDialog.Builder dialogBuilder = new android.app.AlertDialog.Builder(getActivity());
        final LayoutInflater inflater = getActivity().getLayoutInflater();
        final View dialogView = inflater.inflate(R.layout.popup_confirm_delete, null);
        dialogBuilder.setView(dialogView);

        dialogBuilder.setTitle("Delete?");

        dialogBuilder.setNegativeButton(getString(R.string.activities_confirm_deletion_cancel_button), new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int whichButton) {
            }
        });
        dialogBuilder.setPositiveButton(getString(R.string.activities_confirm_deletion_delete_button), new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int whichButton) {
                ((DialogListener) getActivity()).onDeleteConfirm();
            }
        });

        deleteDialog = dialogBuilder.create();
        deleteDialog.show();
        return deleteDialog;
    }

    public interface DialogListener {
        void onDeleteConfirm();
    }
}
</code></pre>

<p>Obviously, this interface only works when the dialog is created in an <code>Activity</code> (<code>((DialogListener) getActivity()).onDeleteConfirm();</code>). For the problem mentioned above, I need to create the dialog from within a <code>Listfragment</code>, and just implementing the dialog interface in the <code>ListFragment</code> does not work ("Activity must implement ConfirmDeletePopupFragment.DialogListener")</p>

<p>What would be the best way to adapt my <code>DialogFragment</code> so it would accommodate both cases (created in <code>Activity</code> or <code>Fragment</code>)?</p>