Activityと(Dialog)Fragmentの連携をどうやるか

DemoDialogFragment.java

public class DemoDialogFragment extends DialogFragment {
    public static DialogFragment newInstance(int requestCode) {
        DialogFragment dialog = new DemoDialogFragment();
        Bundle args = new Bundle();
        args.putBoolean(ARGS_CALLER_ACTIVITY, true);
        args.putInt(ARGS_REQUEST_CODE, requestCode);
        dialog.setArguments(args);
        return dialog;
    }

    public static DialogFragment newInstance(Fragment target, int requestCode) {
        DialogFragment dialog = new DemoDialogFragment();
        dialog.setTargetFragment(target, requestCode);

        Bundle args = new Bundle();
        args.putBoolean(ARGS_CALLER_ACTIVITY, false);
        dialog.setArguments(args);
        return dialog;
    }

    // 中略

    // ダイアログでOKが押された時にこれが呼ばれるとする
    void submit() {
        Bundle args = getArguments();
        boolean isCallerActivity = args.getBoolean(ARGS_CALLER_ACTIVITY);
        if (isCallerActivity) {
            int requestCode = args.getInt(ARGS_REQUEST_CODE);

            MyActivity activity = getActivity();
            if (activity == null) { return; }
            activity.onDialogResult(requestCode); // なんらかのメソッドで結果を伝える
        } else {
            Fragment target = getTargetFragment();
            if (target == null) { return; }

            target.onActivityResult(getTargetRequestCode(), Activity.RESULT_OK, null);
        }
    }
}