带有自定义 UIView（包括按钮）的 UIViewController 无法识别水龙头

Question

当尝试以编程方式将包含 UIButton 的自定义 UIView (BaseHeader.swift) 加载到 UIViewController (ViewController.swift) 中时，按钮上的点击不被识别。

如果我在自定义 UIView 中提取代码并将其直接粘贴到 UIViewController 中，则所有点击都会被识别并按预期工作。我错过了什么？

起初，我认为在 UIView 实例化后没有为其定义帧大小是一个问题。我认为按钮可能没有“命中框”，尽管它按预期显示。在给视图一个框架之后，我仍然没有运气，并在谷歌搜索了一段时间后尝试了其他各种方法。

The view loads but button taps are not recognized -- see image

ViewController.swift

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        self.title = "Authentication"
    }

    override func loadView() {
        super.loadView()

        let header = BaseHeader()
        header.translatesAutoresizingMaskIntoConstraints = false
        self.view.addSubview(header)

        NSLayoutConstraint.activate([
            header.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
            header.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),
            header.topAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.topAnchor, constant: -10),
        ])
    }
}

BaseHeader.swift

import UIKit

class BaseHeader: UIView {

    override init(frame: CGRect) {
        super.init(frame: frame)
        setupView()
    }

    required init?(coder: NSCoder) {
        super.init(coder: coder)
    }

    func setupView() {

        self.isUserInteractionEnabled = true

        let avenirFont = UIFont(name: "Avenir", size: 40)
        let lightAvenirTitle = avenirFont?.light

        let title = UILabel()
        title.text = "Title"
        title.font = lightAvenirTitle
        title.textColor = .black
        title.translatesAutoresizingMaskIntoConstraints = false
        self.addSubview(title)

        NSLayoutConstraint.activate([
            title.topAnchor.constraint(equalTo: self.topAnchor, constant: 20),
            title.centerXAnchor.constraint(equalTo: self.centerXAnchor)
        ])


        let profile = UIButton()
        let profileImage = UIImage(named: "person-icon")
        profile.setImage(profileImage, for: .normal)
        profile.setImage(UIImage(named: "think-icon"), for: .highlighted)
        profile.addTarget(self, action: #selector(profileTapped), for: .touchUpInside)
        profile.backgroundColor = .systemBlue
        profile.frame.size = CGSize(width: 30, height: 30)
        profile.isUserInteractionEnabled = true
        profile.translatesAutoresizingMaskIntoConstraints = false
        self.addSubview(profile)

        NSLayoutConstraint.activate([
            profile.centerYAnchor.constraint(equalTo: title.centerYAnchor),
            profile.trailingAnchor.constraint(equalTo: self.trailingAnchor, constant: -20),
        ])
    }

    @objc func profileTapped(sender: UIButton) {
        print("Tapped")
    }
}

Answer 1

可能是您为自定义视图调用了错误的初始化程序，并且您的 setupView() 函数没有被调用。它看起来像在您正在调用的视图控制器中

let header = BaseHeader()

要初始化视图，不过是这个初始化：

override init(frame: CGRect) {
    super.init(frame: frame)
    setupView()
}

这会调用您的 setupView() 函数并设置水龙头。

Answer 2

您忘记为 BaseHeader 设置高度

 NSLayoutConstraint.activate([
            header.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
            header.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),
            header.topAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.topAnchor, constant: -10),
header.heightAnchor.constraint(equalToConstant: 40) //add more
        ])