activity theme

<style name="DialogTransparent" parent="Theme.AppCompat.Light.NoActionBar">
        <item name="android:windowNoTitle">true</item>
        <item name="android:windowIsFloating">true</item>
        <item name="android:windowBackground">@android:color/transparent</item>
</style>

让activity全屏显示

getWindow().setLayout(ViewGroup.LayoutParams.MATCH_PARENT,ViewGroup.LayoutParams.MATCH_PARENT);

这行代码必须在setContentView后设置