Swift Xcode 中的游乐场 - UILabel 的 TapGestureRecognizer 不工作

Question

我正在 Xcode 中创建一个 Swift 游乐场，我在将 TapGestureRecognizer 放入 UILabel 时遇到问题...

class MyViewController : UIViewController {

  override func loadView() {

    func tapped() {

        print("The label was tapped!")

    }

    let label11 = UILabel()
    label11.frame = CGRect(x: -350, y: 360, width: 350, height: 20)
    label11.text = "name."
    label11.textColor = .black
    label11.isUserInteractionEnabled = true
    view.addSubview(label11)

    let tap = UITapGestureRecognizer(target: self, action: "tapped")
    label11.addGestureRecognizer(tap)
  }
}

Answer 1

看来您正在以编程方式创建视图控制器，因为您仅在 loadView 中操作（您正确地没有调用 super），这需要您创建实际的 view 那个控制器。

import UIKit
import PlaygroundSupport

class MyViewController: UIViewController {

    override func loadView() {

        view = UIView()

        let label11 = UILabel()
        label11.frame = CGRect(x: 0, y: 360, width: 350, height: 20)
        label11.text = "name."
        label11.textColor = .yellow
        label11.isUserInteractionEnabled = true
        view.addSubview(label11)

        let tap = UITapGestureRecognizer(target: self, action: #selector(tapped))
        label11.addGestureRecognizer(tap)

    }

    @objc func tapped() {
        print("The label was tapped!")
    }

}

PlaygroundPage.current.liveView = MyViewController()

或者，您可以使用 viewDidLoad（这需要您调用 super）来复制 non-programmatic 视图控制器。

import UIKit
import PlaygroundSupport

class MyViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let label11 = UILabel()
        label11.frame = CGRect(x: 0, y: 360, width: 350, height: 20)
        label11.text = "name."
        label11.textColor = .yellow
        label11.isUserInteractionEnabled = true
        view.addSubview(label11)

        let tap = UITapGestureRecognizer(target: self, action: #selector(tapped))
        label11.addGestureRecognizer(tap)

    }

    @objc func tapped() {
        print("The label was tapped!")
    }

}

PlaygroundPage.current.liveView = MyViewController()

此外，您的 origin-x 值超出范围，这就是为什么您可能没有看到标签并且您缺少 Swift 4 中要求的 @objc 语法的原因。 =18=]

Swift Xcode 中的游乐场 - UILabel 的 TapGestureRecognizer 不工作

Swift Playground in Xcode - TapGestureRecognizer to UILabel not working

uilabel

ios

uitapgesturerecognizer

swift

swift-playground