Swift：同时平移和长按识别器

Question

我在 viewController class 级别定义了 longPress 和平移手势识别器，如下所示：

var touch = UILongPressGestureRecognizer()
var pan = UIPanGestureRecognizer()

然后我创建一个简单的 UIView：

let qBox = UIView()
qBox.frame = CGRect(x: 100, y: 200, width: 50, height: 50)
self.view.addSubview(qBox)

然后我配置并添加我的识别器：

touch.addTarget(self, action: "ourTouched:")
touch.minimumPressDuration = 0
touch.numberOfTouchesRequired = 1
touch.numberOfTapsRequired = 0
qBox.addGestureRecognizer(touch)

pan.addTarget(self, action:"pan:")
pan.maximumNumberOfTouches = 1
pan.minimumNumberOfTouches = 1
self.view.addGestureRecognizer(pan)

现在，当我触摸 qBox UIView 时，它会触发 "ourTouched" 方法，但如果我一直按住然后开始平移，它不会拖动 qBox UIView。我尝试在我的 "ourTouched" 函数中添加以下行，以便在用户触摸 qBox UIView 时立即删除长按识别器：

qBox.removeGestureRecognizer(touch)

但是，在第一次触摸和拖动时，只会调用长按方法。我必须放手，然后重新开始平移。我错过了什么？

Answer 1

将 UIGestureRecognizerDelegate 添加到您的识别器，并将其 return YES 添加到 shouldRecognizeSimultaneously。

{
  // setup ...
  touch.delegate = self
}

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWithGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool {
  return (gestureRecognizer == touch && otherGestureRecognizer == pan)
}

更新：Swift 4 或更高版本

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
    return (gestureRecognizer == touch && otherGestureRecognizer == pan)
 }