无法将 UITapGestureRecognizer 和 UILongPressGestureRecognizer 添加到 UIButton答案

【问题标题】：Not able to add UITapGestureRecognizer and UILongPressGestureRecognizer to a UIButton无法将 UITapGestureRecognizer 和 UILongPressGestureRecognizer 添加到 UIButton
【发布时间】：2019-09-14 13:00:49
【问题描述】：

我正在使用以下代码 sn-p 添加手势识别器：

let tapGesture = UITapGestureRecognizer(target: self, action: #selector(attachImage))
    let longGesture = UILongPressGestureRecognizer(target: self, action: #selector(longPress))
    tapGesture.numberOfTapsRequired = 1
    cell.image.addGestureRecognizer(tapGesture)
    cell.image.addGestureRecognizer(longGesture)

@objc func longPress(_ btn : UIButton) {
        selectedImageIndex = btn.tag
    }
@objc func attachImage(_ btn : UIButton) {
        selectedImageIndex = btn.tag
    }

当我按下按钮时出现以下错误

无法识别的选择器发送到实例 0x2802ec000

【问题讨论】：

标签： ios swift iphone uibutton

【解决方案1】：

如果您在imageView 上添加手势，则必须启用isUserInteractionEnabled。

imageView.isUserInteractionEnabled = true

如果你在UIButton 上添加手势，那么

@IBOutlet weak var button: UIButton!

override func viewDidLoad() {

    let tapGesture = UITapGestureRecognizer(target: self, #selector (tapGestureActionHandler(_:)))  //Tap function will call when user tap on button
    let longGesture = UILongPressGestureRecognizer(target: self, #selector(longGestureActionHandler(_:)))  //Long function will call when user long press on button.
    tapGesture.numberOfTapsRequired = 1
    button.addGestureRecognizer(tapGesture)
    button.addGestureRecognizer(longGesture)
}

@objc func tapGestureActionHandler(_ gesture: UITapGestureRecognizer) {

    print("Tap happend")
}

@objc func longGestureActionHandler(_ gesture: UILongPressGestureRecognizer) {

    print("Long press")
}

【讨论】：

【解决方案2】：

如下改变函数

@objc func longPress(_ sender : UILongPressGestureRecognizer) {
    if let btn = sender.view {
        selectedImageIndex = btn.tag
    }
}
@objc func attachImage(_ sender : UITapGestureRecognizer) {
    if let btn = sender.view {
        selectedImageIndex = btn.tag
    }
}

并改变手势初始化如下

let tapGesture = UITapGestureRecognizer(target: self, action: #selector(attachImage(_:)))
let longGesture = UILongPressGestureRecognizer(target: self, action: #selector(longPress(_:)))

【讨论】：