i am getting exception when trying to call requestWindowFeature.
I have tried both adding it before and after the onCreate
    requestWindowFeature(Window.FEATURE_NO_TITLE)
    super.onCreate(savedInstanceState)
    getWindow()!!.setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
            WindowManager.LayoutParams.FLAG_FULLSCREEN)
    getWindow()!!.requestFeature(Window.FEATURE_ACTION_BAR)
it is running smoothly on api 28 but not working on api level 23
 
    