ios – 未调用UITapGestureRecognizer选择器

在我的主窗口的根视图控制器类中,我设置了一个UITapGestureRecognizer属性.在调用重写的viewDidLoad函数期间,我已通过addGestureRecognizer方法将此属性添加到图像属性.我还将image.isUserInteractionEnabled设置为true.

override func viewDidLoad() {
   image.addGestureRecognizer(tap)
   image.isUserInteractionEnabled = true

   self.view.addSubview(image)
}

var tap = UITapGestureRecognizer(target: self, action: #selector(imagePressed(_ :)))

遗憾的是,这不会导致运行时调用imagePressed().令我困惑的是,以下代码产生了预期的结果.

override func viewDidLoad() {
   var tap = UITapGestureRecognizer(target: self, action:#selector(imagePressed(_ :)))
   image.addGestureRecognizer(tap)
   image.isUserInteractionEnabled = true

   self.view.addSubview(image)
}

所以我的问题是,为什么在第一种情况下不会调用UITapGestureRecognizer的选择器?

使用Swift 3和Xcode 8.2.1

最佳答案 我认为这里的问题是addGestureRecognizer.

尝试将viewDidLoad更改为:

override func viewDidLoad() {
    var tap = UITapGestureRecognizer(target: self, action:#selector(imagePressed(_ :)))
    image.isUserInteractionEnabled = true

    self.view.addSubview(image)

    image.addGestureRecognizer(tapGesture)
}
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