Android：某些屏幕的Dialog上没有填充

Question

这里是我的代码：

public class MyDialogFragment extends DialogFragment {

    public static MyDialogFragment newInstance() {
        final MyDialogFragment fragment = new MyDialogFragment ();

        return fragment;
    }

    @Override
    public void onCreate(final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setStyle(STYLE_NO_FRAME, R.style.MyDialog);
    }

    @Override
    public void onStart() {
        super.onStart();

        Window window = getDialog().getWindow();
        WindowManager.LayoutParams windowParams = window.getAttributes();
        windowParams.dimAmount = 0.50f;
        windowParams.flags |= WindowManager.LayoutParams.FLAG_DIM_BEHIND;
        window.setAttributes(windowParams);
    }

@Override
public View onCreateView(final LayoutInflater inflater, final ViewGroup container,
            final Bundle savedInstanceState) {
    final View view = inflater.inflate(R.layout.dialog, container, false);

/* some init code for TextView and buttons here */

        return view;

}

styles.xml：

<style name="MyDialog" parent="CustomDialog"></style>
<style name="CustomDialog" parent="@android:style/Theme.Light.Panel" />

它不是在Nexus 4/5设备上复制，而是在Desire S（hdpi，480x800）上复制。

请问有人帮我解决这个问题吗？