class NavigationDrawerActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_navigation_drawer)
        setSupportActionBar(toolBar)
        title = "Navigation Drawer Activity"
        supportActionBar!!.setDisplayHomeAsUpEnabled(true)
        supportActionBar!!.setDisplayShowTitleEnabled(false)
        setUpDrawerToggle()
        NavigationUI.setupWithNavController(navView, Navigation.findNavController(this, R.id.navDrawerActivity)) // here navView using Kotlin extension to avoid findviewbyid
    }
}