1-) Android RMOS - navigationView navController DrawerLayout button visible false hide menu

public NavigationView navigationView;

...

navigationView = findViewById(R.id.nav_view);

navigationView = (NavigationView) findViewById(R.id.nav_view);
Menu nav_Menu = navigationView.getMenu();
nav_Menu.findItem(R.id.nav_grup).setVisible(hizliSiparis);