Background transparent style.xml
<item name="android:windowBackground">@color/transparent</item>
<item name="android:windowIsTranslucent">true</item>
Reproduced in: https: //my.oschina.net/zhouz/blog/213193
Background transparent style.xml
<item name="android:windowBackground">@color/transparent</item>
<item name="android:windowIsTranslucent">true</item>
Reproduced in: https: //my.oschina.net/zhouz/blog/213193