ios - 添加到 UILabel 的点击手势识别器不起作用

Question

我使用以下代码将手势识别器添加到 UILabel。 Storyboard中的标签已启用用户交互，但当我点击标签时，不会调用 onUserClickingSendToken 方法。

class ViewController: UIViewController, MFMailComposeViewControllerDelegate {

    @IBOutlet weak var tokenDisplay: UILabel!
    var tapGestureRecognizer:UITapGestureRecognizer = UITapGestureRecognizer(target:self, action:  #selector(onUserClickingSendToken(_:)))

    override func viewDidLoad() {
        super.viewDidLoad()
        tapGestureRecognizer.numberOfTapsRequired = 1
        tokenDisplay.addGestureRecognizer(tapGestureRecognizer)
    }

    func onUserClickingSendToken(_ sender: Any)
    {
      ....

Answer 1

初始化 viewDidLoad 中的 tapRecognizer 应该可以做到，因为您在初始化 View 之前以自身为目标

class ViewController: UIViewController, MFMailComposeViewControllerDelegate {

@IBOutlet weak var tokenDisplay: UILabel!
var tapGestureRecognizer:UITapGestureRecognizer!

override func viewDidLoad() {
    super.viewDidLoad()
    tapGestureRecognizer = UITapGestureRecognizer(target:self, action:      #selector(onUserClickingSendToken(_:)))
    tapGestureRecognizer.numberOfTapsRequired = 1
    tokenDisplay.isUserInteractionEnabled = true
    tokenDisplay.addGestureRecognizer(tapGestureRecognizer)
}

@objc func onUserClickingSendToken(_ sender: Any)
{
  ....