Swift: Use of unresolved identifier 'present' - ios

Question

I have a UIView added to UIViewController, and some code of them
ViewController.swift
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
let listView = ListView()
self.view.addSubview(listView)
}
ListView.swift
class ListView: UIView {
override init(frame: CGRect) {
super.init(frame: frame)
self.addSubview(btnGO)
}
convenience init() {
self.init(frame: CGRect.zero)
}
required init(coder aDecoder: NSCoder) {
fatalError("This class does not support NSCoding")
}
lazy var btnGO:(UIButton) = {
let btn = UIButton(frame: CGRect(x: 0, y: 0, width: 44, height: 34))
btn.addTarget(self, action: #selector(btnClicked), for: .touchUpInside)
//some codes
return btn
}()
#objc func btnClicked(sender:UIButton) {
let shareWOW = "some content"
let objectsToShare = [shareWOW]
let activityController = UIActivityViewController(
activityItems: objectsToShare,
applicationActivities: nil)
activityController.popoverPresentationController?.sourceRect = self.frame
activityController.popoverPresentationController?.sourceView = self
activityController.popoverPresentationController?.permittedArrowDirections = .any
present(activityController, animated: true, completion: nil)
}
}
I always get error information Use of unresolved identifier 'present', and I know UIActivityViewController should be placed in UIViewController, and my question is I place the function btnClicked in ViewController.swift, how to call this function in a UIView as ListView.swift? Many thanks

Answer 1

present(_:animated:completion:) method should be used with UIViewController instance. You can't call this method in a UIView subclass. Use delegate to call a method in ViewController from ListView and present UIActivityViewController from the ViewController like this
ViewController.swift
class ViewController: UIViewController, ListViewDelegate {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
let listView = ListView()
listView.delegate = self
self.view.addSubview(listView)
}
func btnClicked(sender: UIButton) {
let shareWOW = "some content"
let objectsToShare = [shareWOW]
let activityController = UIActivityViewController(
activityItems: objectsToShare,
applicationActivities: nil)
activityController.popoverPresentationController?.sourceRect = sender.frame
activityController.popoverPresentationController?.sourceView = sender
activityController.popoverPresentationController?.permittedArrowDirections = .any
self.present(activityController, animated: true, completion: nil)
}
}
ListView.swift
protocol ListViewDelegate {
func btnClicked(sender:UIButton)
}
class ListView: UIView {
var delegate: ListViewDelegate?
override init(frame: CGRect) {
super.init(frame: frame)
self.addSubview(btnGO)
}
convenience init() {
self.init(frame: CGRect.zero)
}
required init(coder aDecoder: NSCoder) {
fatalError("This class does not support NSCoding")
}
lazy var btnGO:(UIButton) = {
let btn = UIButton(frame: CGRect(x: 0, y: 0, width: 44, height: 34))
btn.addTarget(self, action: #selector(btnClicked), for: .touchUpInside)
//some codes
return btn
}()
#objc func btnClicked(sender:UIButton) {
delegate?.btnClicked(sender: sender)
}
}