Change the value of another class (Extension) with argument - ios

Question

A function whose argument is used for Extension of another class is described.
I want to change the value of the UIView property (alpha) that exists in that function "at the button tap in another class".
However, this function can be changed at ViewDidLoad time.
How can I change the value when tapping buttons?
If possible please write the code.
ViewController Class
class ViewController: UIViewController {
#IBOutlet weak var vHome: UICollectionView!
#IBOutlet weak var vSearch: UICollectionView!
override func viewDidLoad() {
super.viewDidLoad()
selectRd(rd: 3) //This time can change calue of alpha.
}
}
extension ViewController {
func selectRd(rd reader:Int){
var animateView:UIView!
let animateVHome = vHome
let animateVSearch = vSearch
UIView.animate(withDuration: 0.3, delay: 0.0, animations: {
animateVHome.alpha = 0.0
animateVSearch.alpha = 0.0
}, completion: nil)
switch reader {
case 2:
animateView = animateVHome
case 3:
animateView = animateVSearch
default:
break
}
UIView.animate(withDuration: 0.3, delay: 0.3, animations: {
animateView.alpha = 1.0
}, completion: nil)
}
}
Another Class
class Another{
#objc func buttonTapped(sender : HeaderButton) {
let vC = ViewController
vC.selectRd(rd: 2) //This time can not!!
}
}
Please comment if you can not understand the question.

Answer 1

The problem is that you can't access a function of a class if its currently active , as this will result in a crash , so Add a var in viewControler
class ViewController: UIViewController {
#IBOutlet weak var vHome: UICollectionView!
#IBOutlet weak var vSearch: UICollectionView!
var index:Int?
override func viewDidLoad() {
super.viewDidLoad()
selectRd(rd: self.index) //This time can change calue of alpha.
}
}
..
class Another{
#objc func buttonTapped(sender : HeaderButton) {
let vC = ViewController
vC.index = 2 //This time can not!!
}
}