FullScreen View

//--------------- start style.xml --------------

<style name="Fullscreen" parent="AppTheme">
    <item name="android:windowNoTitle">true</item>
    <item name="android:windowActionBar">false</item>
    <item name="android:windowFullscreen">true</item>
    <item name="android:windowContentOverlay">@null</item>

</style>

//--------------- end style.xml --------------

//--------------- AndroidManisfest.xml ---------------

minSdkVersion 21targetSdkVersion 27

<uses-sdk   

 android:maxSdkVersion="27"    

android:minSdkVersion="21"    

android:targetSdkVersion="26" />

<application   android:theme="@style/Fullscreen">

</application>

//--------------- end AndroidManisfest.xml ---------------

//------------------ --------    MainActivity.java . --------------------

extends Activity {

protected void onCreate(Bundle savedInstanceState) {
 //   getWindow().addFlags(WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN);  //  getWindow().addFlags(WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS);   

 hideSystemUI();
   

 super.onCreate(savedInstanceState);
    

showSystemUI();
    

}

}

 // This snippet hides the system bars.    private void hideSystemUI() {
        // Set the IMMERSIVE flag.        // Set the content to appear under the system bars so that the content        // doesn't resize when the system bars hide and show.        View decorView = getWindow().getDecorView();
        decorView.setSystemUiVisibility(
                View.SYSTEM_UI_FLAG_LAYOUT_STABLE                        | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION                        | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN                        | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION // hide nav bar                        | View.SYSTEM_UI_FLAG_FULLSCREEN // hide status bar                        | View.SYSTEM_UI_FLAG_IMMERSIVE);
    }

    // This snippet shows the system bars. It does this by removing all the flags// except for the ones that make the content appear under the system bars.    private void showSystemUI() {
        View decorView = getWindow().getDecorView();
        decorView.setSystemUiVisibility(
                View.SYSTEM_UI_FLAG_LAYOUT_STABLE                        | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION                        | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
    }
}

//------------------ --------  End   MainActivity.java . --------------------