ios - 除非我指定正确的 CGRect，否则 UIView 上的按钮没有响应

Question

我正在尝试实现一个简单的 UIView，当互联网连接丢失时，它会显示在屏幕底部，并且会有一个关闭按钮。我的 UIView 类看起来像这样。

import UIKit

class ConnectionLostAlertUIView: UIView {

    @IBOutlet var view: UIView!
    var viewConstraints: [NSLayoutConstraint] = []

    override init(frame: CGRect) {
        super.init(frame: frame)
        Bundle.main.loadNibNamed("ConnectionLostAlertView", owner: self, options: nil)
        self.addSubview(self.view)
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        Bundle.main.loadNibNamed("ConnectionLostAlertView", owner: self, options: nil)
        self.addSubview(self.view)
    }

    override func didMoveToSuperview() {

        view.translatesAutoresizingMaskIntoConstraints = false

        let bottomConstraint =     view.bottomAnchor.constraint(equalTo: self.superview!.bottomAnchor)
        let leftConstraint = view.leadingAnchor.constraint(equalTo: self.superview!.leadingAnchor)
        let rightConstraint = view.trailingAnchor.constraint(equalTo: self.superview!.trailingAnchor)

        viewConstraints = [bottomConstraint, leftConstraint, rightConstraint]
        NSLayoutConstraint.activate(viewConstraints)
    }

    @IBAction func dismissButton(_ sender: Any) {
        Logger.log(message: "Dismiss button was pressed", event: .d)
        self.isHidden = true
    }

然后我通过执行以下操作将此 UIView 添加到我的 UIViewController

var ConnectionLostAlert: ConnectionLostAlertUIView!
ConnectionLostAlert = ConnectionLostAlertUIView(frame: CGRect.zero)
self.view.addSubview(ConnectionLostAlert)

好吧，我可以为 CGRect 使用实际值而不是零，但问题是在我的 UIView 中添加约束后，我的 UIView 中的按钮停止响应。如果我实际上设置了一些 CGRect 坐标并且不在 UIView 中使用约束，它就可以正常工作。有没有更好的方法来完成我正在努力实现的目标，它仍然允许我处理 UIView 内的按钮事件？

Answer 1

问题是您正在从内部 View 添加约束，即 View 到 super View ，跳过实际上被添加到 super View 的主视图 (ConnectionLostAlertUIView)。

您应该做的是首先在 view 和 self 之间添加约束。然后当 self(ConnectionLostAlertUIView) 添加到 superview 时，然后添加与 super view 的约束。

做这样的事情:

@IBOutlet var view: UIView!
var viewConstraints: [NSLayoutConstraint] = []

override init(frame: CGRect) {
    super.init(frame: frame)
    Bundle.main.loadNibNamed("ConnectionLostAlertView", owner: self, options: nil)
    self.addSubview(self.view)

    view.translatesAutoresizingMaskIntoConstraints = false

    let bottomConstraint =     view.bottomAnchor.constraint(equalTo: self.bottomAnchor)
    let leftConstraint = view.leadingAnchor.constraint(equalTo: self.leadingAnchor)
    let rightConstraint = view.trailingAnchor.constraint(equalTo: self.trailingAnchor)

    viewConstraints = [bottomConstraint, leftConstraint, rightConstraint]
    NSLayoutConstraint.activate(viewConstraints)
}

required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    Bundle.main.loadNibNamed("ConnectionLostAlertView", owner: self, options: nil)
    self.addSubview(self.view)
}

override func didMoveToSuperview() {

    self.translatesAutoresizingMaskIntoConstraints = false

    let bottomConstraint =     self.bottomAnchor.constraint(equalTo: self.superview!.bottomAnchor)
    let leftConstraint = self.leadingAnchor.constraint(equalTo: self.superview!.leadingAnchor)
    let rightConstraint = self.trailingAnchor.constraint(equalTo: self.superview!.trailingAnchor)

    viewConstraints = [bottomConstraint, leftConstraint, rightConstraint]
    NSLayoutConstraint.activate(viewConstraints)
}

@IBAction func dismissButton(_ sender: Any) {
    Logger.log(message: "Dismiss button was pressed", event: .d)
    self.isHidden = true
}