在 iOS 12.2 上，使用UIAlertController'sactionSheet时，Xcode 会出现约束错误。有人遇到这个问题吗？
相同的代码在 iOS 12.1 上运行，没有错误。
我已经在 Xcode 10.2 和 10.1 上测试了这段代码。
class ViewController: UIViewController {
let Click : UIButton = {
let button = UIButton(type: UIButton.ButtonType.system)
button.translatesAutoresizingMaskIntoConstraints = false
button.setTitle("OK", for: .normal)
button.tintColor = UIColor.blue
button.addTarget(self, action: #selector(click(_:)), for: UIControl.Event.touchUpInside)
return button
}()
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(Click)
Click.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
Click.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
}
@objc func click(_ sender: UIButton) {
let optionMenu = UIAlertController(title: nil, message: "Choose Option", preferredStyle: .actionSheet)
let deleteAction = UIAlertAction(title: "Delete", style: .default)
let saveAction = UIAlertAction(title: "Save", style: .default)
let cancelAction = UIAlertAction(title: "Cancel", style: .cancel)
optionMenu.addAction(deleteAction)
optionMenu.addAction(saveAction)
optionMenu.addAction(cancelAction)
self.present(optionMenu, animated: true, completion: nil)
}
}
[LayoutConstraints] Unable to simultaneously satisfy constraints.
Probably at least one of the constraints in the following list is one you don't want.
Try this:
(1) look at each constraint and try to figure out which you don't expect;
(2) find the code that added the unwanted constraint or constraints and fix it.
(
"<NSLayoutConstraint:0x6000001b6ee0 UIView:0x7fe3b6513020.width == - 16 (active)>"
)
Will attempt to recover by breaking constraint
<NSLayoutConstraint:0x6000001b6ee0 UIView:0x7fe3b6513020.width == - 16 (active)>
PS：
只是为了确保问题存在UIAlertController，我删除了所有内容并更新了如下代码，但我收到了同样的错误：
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
let optionMenu = UIAlertController(title: "Test", message: "Choose Option", preferredStyle: .actionSheet)
let deleteAction = UIAlertAction(title: "Delete", style: .default)
let saveAction = UIAlertAction(title: "Save", style: .default)
let cancelAction = UIAlertAction(title: "Cancel", style: .cancel)
optionMenu.addAction(deleteAction)
optionMenu.addAction(saveAction)
optionMenu.addAction(cancelAction)
self.present(optionMenu, animated: true, completion: nil)
}
}