透明的谷歌地图上PopupWindow？

我在 PopupWindow 使用谷歌地图（V2），当我运行应用程序，将不显示地图。即使它应该是该地区是完全透明的，我可以透过它看到下面的 PopupWindow 活动。

I have used a Google Maps (V2) in a PopupWindow and when I run the application, the map is not displayed. Even the area where it should be is fully transparent and I can see the activity below the PopupWindow through it.

任何想法，这是为什么？

Any idea why this is?

里面的片段popup_window.xml

<fragment
    android:id="@+id/popup_alert_map"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_below="@+id/popup_alert_description"
    android:layout_marginTop="10dp"
    class="com.google.android.gms.maps.SupportMapFragment" />

我该如何证明它里面Popup.java

SupportMapFragment supportMapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.popup_alert_map);
locationMap = supportMapFragment.getMap();

locationMap.setMyLocationEnabled(true);
locationMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);

我有另一个活动与地图它和它的是的显示器很好。

I have another Activity with a map it it and that displays nicely.

任何帮助非常AP preciated ...

Any help greatly appreciated...