HogeActivity.java

    @Override
    public void onClick(View v) {

        HogeDialogFragment fragment = new HogeDialogFragment();

        // 必要なパラメータがあればsetArgument

        // requestCodeが37になる
        fragment.setTargetFragment(null,37);
        fragment.show(getFragmentManager(), "dialog");
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == 37)
            Log.d("HogeDialogFragmentResult", Integer.toString(requestCode));
    }

HogeDialogFragment.java

    @Override
    public void onClick(DialogInterface dialog, int which) {
        Intent result = new Intent();

        // 他にパラメータが必要ならこの辺で適当にputExtra

        if (getTargetFragment() != null) {
            getTargetFragment().onActivityResult(getTargetRequestCode(), Activity.RESULT_OK, result);
        } else {
            PendingIntent pi = getActivity().createPendingResult(getTargetRequestCode(), result,
                    PendingIntent.FLAG_ONE_SHOT);
            try {
                pi.send();
            } catch (PendingIntent.CanceledException ex) {
                // send failed
            }
        }
    }