小编mod*_*dew的帖子

在主窗口的根视图控制器类中，我设置了UITapGestureRecognizer属性。在调用覆盖的viewDidLoad函数的过程中，我已通过addGestureRecognizer方法将此属性添加到图像属性。我也将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(_ :)))

可悲的是，这不会导致在运行时调用imagePressed（）。令我感到困惑的是，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未调用UITapGestureRecognizer的选择器？

使用Swift 3和Xcode 8.2.1

我遇到了以下代码片段:

(defstructure object
  "An object is anything that occupies space.  Some objects are 'alive'."
  (name "?")            ; Used to print the object on the map
  (alive? nil)                  ; Is the object alive?
  (loc (@ 1 1))         ; The square that the object is in
  (bump nil)            ; Has the object bumped into something?
  (size 0.5)            ; Size of object as proportion of loc
  (color 'black)        ; Some objects have a color
  (shape 'rectangle)        ; Some objects have a shape
  (sound …