I hide in this way ActionBar
<style name="AppTheme" parent="Theme.AppCompat.NoActionBar"> <!-- Customize your theme here. --> <item name="windowNoTitle">true</item> <item name="windowActionBar">false</item> </style> After that, it disappears, but the application stops working correctly, the essence of the application is WebView, and a couple of local pages are nothing complicated, the application loads, after the click, a black screen, although if you don’t hide the ActionBar