Swift button from nested UIView is not clickable - ios

Question

I have a ViewController and another UIView called MySubview which contains a simple button.
If I add MySubview into ViewController the button is unclickable. However if I put the button directly inside ViewController everything works as expected.
Example:
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let button = MySubview()
view.addSubview(button)
button.translatesAutoresizingMaskIntoConstraints = false
button.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 0).isActive = true
button.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 0).isActive = true
}
}
class MySubview: UIView {
let button: UIButton = {
let button = UIButton()
button.setTitle("MyButton", for: .normal)
button.setTitleColor(.label, for: .normal)
button.addTarget(self, action: #selector(myfunc), for: .touchUpInside)
return button
}()
#objc func myfunc() {
print("clicked")
}
override init(frame: CGRect) {
super.init(frame: frame)
backgroundColor = .red
addSubview(button)
button.translatesAutoresizingMaskIntoConstraints = false
button.topAnchor.constraint(equalTo: topAnchor, constant: 0).isActive = true
button.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 0).isActive = true
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
When I click on the button I do not see printed message.

Answer 1

Your code is confused, if I understand well take a look to my code below, declare your button and your view under your controller class:
class ViewController: UIViewController {
let button: UIButton = {
let button = UIButton()
button.setTitle("MyButton", for: .normal)
button.setTitleColor(.white, for: .normal)
button.backgroundColor = .black
button.addTarget(self, action: #selector(myfunc), for: .touchUpInside)
return button
}()
let mysubview = UIView()
...
now in viewDidLoad set constraints like this:
override func viewDidLoad() {
super.viewDidLoad()
mysubview.backgroundColor = .red
view.addSubview(mysubview)
mysubview.translatesAutoresizingMaskIntoConstraints = false
mysubview.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 0).isActive = true
mysubview.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 0).isActive = true
mysubview.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: 0).isActive = true
mysubview.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor, constant: 0).isActive = true
mysubview.addSubview(button)
button.translatesAutoresizingMaskIntoConstraints = false
button.topAnchor.constraint(equalTo: mysubview.topAnchor, constant: 20).isActive = true
button.leadingAnchor.constraint(equalTo: mysubview.leadingAnchor, constant: 20).isActive = true
button.trailingAnchor.constraint(equalTo: mysubview.trailingAnchor, constant: -20).isActive = true
button.heightAnchor.constraint(equalToConstant: 50).isActive = true
}
now add your func
#objc func myfunc() {
print("clicked")
}
complete code:
import UIKit
class ViewController: UIViewController {
let button: UIButton = {
let button = UIButton()
button.setTitle("MyButton", for: .normal)
button.setTitleColor(.white, for: .normal)
button.backgroundColor = .black
button.addTarget(self, action: #selector(myfunc), for: .touchUpInside)
return button
}()
let mysubview = UIView()
override func viewDidLoad() {
super.viewDidLoad()
mysubview.backgroundColor = .red
view.addSubview(mysubview)
mysubview.translatesAutoresizingMaskIntoConstraints = false
mysubview.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 0).isActive = true
mysubview.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 0).isActive = true
mysubview.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: 0).isActive = true
mysubview.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor, constant: 0).isActive = true
mysubview.addSubview(button)
button.translatesAutoresizingMaskIntoConstraints = false
button.topAnchor.constraint(equalTo: mysubview.topAnchor, constant: 20).isActive = true
button.leadingAnchor.constraint(equalTo: mysubview.leadingAnchor, constant: 20).isActive = true
button.trailingAnchor.constraint(equalTo: mysubview.trailingAnchor, constant: -20).isActive = true
button.heightAnchor.constraint(equalToConstant: 50).isActive = true
}
#objc func myfunc() {
print("clicked")
}
}

Answer 2

If your subview has a frame of size zero, you won't be able to tap the button even if you can see it. Using a view debugger from Xcode will show you if this is the issue.
Also, check if the subview has user interaction enabled when adding it.

Answer 3

I think , the problem is in layers (I mean, subviews). Try this instead of view.addSubview(button) :
view.insertSubview(your_button_view, at: view.subviews.count)