如何在FragmentActivity中的onBackPressed事件中传递数据或添加观察者

public interface OnBackPressedListener {
    void onBackPressed(Object data);
}

public class MyFragment extends Fragment implements OnBackPressedListener {
    // ...

    @Override
    public void onBackPressed(Object data) {
        // 处理数据传递或通知观察者
    }
}

public class MyFragmentActivity extends FragmentActivity {
    private OnBackPressedListener onBackPressedListener;

    public void setOnBackPressedListener(OnBackPressedListener listener) {
        this.onBackPressedListener = listener;
    }

    // ...
}

public class MyFragmentActivity extends FragmentActivity {
    // ...

    @Override
    public void onBackPressed() {
        if (onBackPressedListener != null) {
            onBackPressedListener.onBackPressed(data);
        }
        super.onBackPressed();
    }
}