I see viewIsAppearing is available on iOS 13 and above, but when I use it, found that the function not be called below iOS 16
https://developer.apple.com/documentation/uikit/uiviewcontroller/4195485-viewisappearing
environment: Macos 14.4.1, Xcode 15.3
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let sub = SubViewController()
addChild(sub)
view.addSubview(sub.view)
}
@available(iOS 13.0, *)
override func viewIsAppearing(_ animated: Bool) {
super.viewIsAppearing(animated)
print("ViewController viewIsAppearing")
}
}
class SubViewController: UIViewController {
@available(iOS 13.0, *)
override func viewIsAppearing(_ animated: Bool) {
super.viewIsAppearing(animated)
print("SubViewController viewIsAppearing")
}
}
In iOS 15 devcice console log:
ViewController viewIsAppearing
iOS 16, 17:
ViewController viewIsAppearing
SubViewController viewIsAppearing