ios - UITapGestureRecognizer 仅适用于最后一项

Question

我正在创建一个简历应用程序(主要是为了好玩)，但似乎无法让点击手势识别器为我工作。我想要的是让一个标签显示信息，并根据他们在下面点击的标题标签来改变它。这是我写的代码:

import UIKit

class WorkHistoryViewController: UIViewController {

    // MARK: Properties

    @IBOutlet weak var jobOne: UILabel!
    @IBOutlet weak var jobTwo: UILabel!
    @IBOutlet weak var jobThree: UILabel!
    @IBOutlet weak var jobFour: UILabel!
    @IBOutlet weak var jobFive: UILabel!
    @IBOutlet weak var workHistoryDescriptionLabel: UILabel!
    let tapRec = UITapGestureRecognizer()

    override func viewDidLoad() {
        super.viewDidLoad()
        tapRec.addTarget(self, action: "tappedLabel")
        jobOne.addGestureRecognizer(tapRec)
        jobTwo.addGestureRecognizer(tapRec)
        jobThree.addGestureRecognizer(tapRec)
        jobFour.addGestureRecognizer(tapRec)
        jobFive.addGestureRecognizer(tapRec)
    }

    // MARK: Methods

    func tappedLabel() {
        workHistoryDescriptionLabel.text = "It worked!"
    }
}

发生的事情是，最后一个在 viewDidLoad() 中调用 addGestureRecognizer() 的标签是唯一有效的标签。如果我注释掉最后一行，那么只有上面的标签有效。我还尝试以编程方式在每个标签和属性检查器上启用用户交互，但都没有改变任何东西。

Answer 1

根据 Apple 的事件处理指南

Gesture Recognizers Are Attached to a View

Every gesture recognizer is associated with one view. By contrast, a view can have multiple gesture recognizers, because a single view might respond to many different gestures. For a gesture recognizer to recognize touches that occur in a particular view, you must attach the gesture recognizer to that view. When a user touches that view, the gesture recognizer receives a message that a touch occurred before the view object does. As a result, the gesture recognizer can respond to touches on behalf of the view.

因此您需要创建多个 UITapGestureRecognizer 实例并将它们附加到每个 View ，即使它们执行相同的操作也是如此。

例如，

let tapRecOne = UITapGestureRecognizer()
tapRecOne.addTarget(self, action: "tappedLabel")
jobOne.addGestureRecognizer(tapRecOne)

let tapRecTwo = UITapGestureRecognizer()
tapRecTwo.addTarget(self, action: "tappedLabel")
jobTwo.addGestureRecognizer(tapRecTwo)

等等。