ios - UIViewController 子类不识别 UITapGesture

Question

为了稍微精简我的 viewcontroller，我想将 ui 元素和相应的函数移动到一个子类中。但是我的手势不起作用。我该如何解决这个问题？

MyViewController.swift

class MyViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        SubclassMyViewController().setupUserInterface(view: view)
    }

    @objc func doSomething() {
        log.info("logo was tapped")
    }

 }

SubclassMyViewController.swift

class SubclassMyViewController: MyViewController {

    func setupUserInterface(view: UIView) {
        // ...
        view.addSubview(logoImage)
        logoImage.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        logoImage.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
        logoImage.heightAnchor.constraint(equalTo: view.heightAnchor, multiplier: 0.5).isActive = true        

    }

    lazy var logoImage: UIImageView = {
        let imageView = UIImageView()
        imageView.image = UIImage(named: "logo")

        imageView.translatesAutoresizingMaskIntoConstraints = false
        imageView.contentMode = .scaleAspectFit

        // ADD GESTURE 
        let tap = UITapGestureRecognizer(target: self, action: #selector(doSomething))
        imageView.isUserInteractionEnabled = true
        imageView.addGestureRecognizer(tap)

        return imageView
    }()
}

将所有内容放入 Viewcontroller 确实有效。如果我将它分成两类，手势将无法识别。谢谢!

Answer 1

我认为您在这里混淆了一些事情。

SubclassMyViewController().setupUserInterface(view: view) 此行创建了 SubclassMyViewController 的实例，在您的代码示例中它拥有 ImageView 。但是，因为您没有对创建的子类的任何引用，所以一旦该行执行完毕，它就会死掉。

您可以通过创建静态帮助程序类来实现您的目标。这是它的样子。

class MyViewController: UIViewController {

    var imageView: UIImageView!

    override func viewDidLoad() {
        super.viewDidLoad()

        MyViewControllerSetupHelper.setupUserInterface(viewController: self)
    }

    @objc func doSomething() {
        log.info("logo was tapped")
    }

}

class MyViewControllerSetupHelper {

    static func setupUserInterface(viewController: MyViewController) {
        let view = viewController.view!

        let imageView = getLogoImageView()
        viewController.imageView = imageView

        let tapGesture = UITapGestureRecognizer(target: viewController, action: #selector(MyViewController.doSomething))
        imageView.addGestureRecognizer(tapGesture)

        view.addSubview(imageView)

        NSLayoutConstraint.activate([
            imageView.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            imageView.centerYAnchor.constraint(equalTo: view.centerYAnchor),
            imageView.heightAnchor.constraint(equalTo: view.heightAnchor, multiplier: 0.5)
        ])
    }

    static func getLogoImageView() -> UIImageView {
        let imageView = UIImageView()
        imageView.image = UIImage(named: "logo")
        imageView.translatesAutoresizingMaskIntoConstraints = false
        imageView.contentMode = .scaleAspectFit
        imageView.isUserInteractionEnabled = true

        return imageView
    }
}