导读：style name=Theme.Holo.Wallpaper item name=android:windowBackground@android:color/transparent/item item name=android:colorBackgroundCacheHint@null/it......
<style name="Theme.Holo.Wallpaper">
<item name="android:windowBackground">@android:color/transparent</item>
<item name="android:colorBackgroundCacheHint">@null</item>
<item name="android:windowShowWallpaper">true</item>
</style>
直接用Theme_Holo_Wallpaper或者在自定义的Theme中增加这3个item
