Android Studio PWA how to get rid of Action Bar?

Question

android studio

I'm trying to write a PWA application for my site, everything works, but when I start it, the ActionBar flickers, which I disabled in the styles:

<style name="AppTheme" parent="@style/Theme.AppCompat.Light.NoActionBar">
        <item name="windowNoTitle">true</item>
        <item name="windowActionBar">false</item>
        <item name="android:windowNoTitle">true</item>
    </style>

Tell me how to eliminate his short-term appearance?
And how to rewrite the onCreate method of a single activity:

<activity
        android:name="android.support.customtabs.trusted.LauncherActivity">

Where to search and click?
Thank you!