How to set fullscreen in Android R?

KOTLIN

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.layout_container)
    @Suppress("DEPRECATION")
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
        window.insetsController?.hide(WindowInsets.Type.statusBars())
    } else {
        window.setFlags(
            WindowManager.LayoutParams.FLAG_FULLSCREEN,
            WindowManager.LayoutParams.FLAG_FULLSCREEN
        )
    }
}

if this doesn’t help, try to remove android:fitsSystemWindows="true" in the layout file

JAVA

class Activity extends AppCompatActivity {

@Override
@SuppressWarnings("DEPRECATION")
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.layout_container);
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
        final WindowInsetsController insetsController = getWindow().getInsetsController();
        if (insetsController != null) {
            insetsController.hide(WindowInsets.Type.statusBars());
        }
    } else {
        getWindow().setFlags(
                WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN
        );
    }
}
}