touchUpInside 事件未触发

Question

我是 IOS 编程新手，但奇怪的是相同的代码在不同的类中工作，所以我不知道为什么它不工作 它在 Swift 3 中

class BottomMenu : NSObject{

    //Container view
    var bottomView: UIView!    

    //Button
    var buttonContents : UIButton!


    init(bottomView : UIView) {
        super.init()
        self.bottomView = bottomView        

        buttonContents = UIButton(frame: getFrame(index: 0))    
        buttonContents.backgroundColor = UIColor.blue //To see where to click on the screen
        bottomView.addSubview(buttonContents)

        buttonContents.addTarget(self, action: #selector(onClick), for: .touchUpInside)
    }

    func getFrame(index : CGFloat!) -> CGRect{
        let screenW = UIScreen.main.bounds.width
        return CGRect(x: (screenW/3) * index,
                           y: 0,
                           width: screenW/3,
                           height: self.bottomView.frame.size.height)
    }    
    func onClick(sender: UIButton!){
        NSLog("click")
    }

}

这是这个类的实现：

let bottomMenu = BottomMenu(bottomView: bottomNavBarContainer)

所以，“点击”日志永远不会显示

Answer 1

您的代码在 Playground 中运行良好。错误必须在类的使用中。父视图禁用了 userInteraction 等。

import UIKit
import Foundation
import PlaygroundSupport

class BottomMenu : NSObject{

//Container view
var bottomView: UIView!

//Button
var buttonContents : UIButton!


init(bottomView : UIView) {
    super.init()
    self.bottomView = bottomView

    buttonContents = UIButton(frame: getFrame(index: 0))
    buttonContents.backgroundColor = UIColor.blue //To see where to click on the screen
    bottomView.addSubview(buttonContents)

    buttonContents.addTarget(self, action: #selector(onClick), for: .touchUpInside)
}

func getFrame(index : CGFloat!) -> CGRect{
    let screenW = UIScreen.main.bounds.width
    return CGRect(x: (screenW/3) * index,
                  y: 0,
                  width: screenW/3,
                  height: self.bottomView.frame.size.height)
}
func onClick(sender: UIButton!){
    NSLog("click")
}

}

var container = UIView(frame: CGRect(x: 0.0, y: 0.0, width: 100.0, height: 100.0))
let view = UIView(frame: CGRect(x: 0.0, y: 0.0, width: 100.0, height: 100.0))
container.addSubview(view)
let buttonContents = BottomMenu(bottomView: view)

PlaygroundPage.current.liveView = container

Answer 2

NSObject 不是 UIResponder，所以它不能处理 UIEvent。一个解决方案可能是让类从 UIView 继承而不是 NSObject 或公开按钮以在 ViewController 内添加目标。

Answer 3

选择器#selector(onClick) 表示一个没有参数的函数。你的 onClick 函数只有一个参数，所以选择器应该是#selector(onClick(sender:))。至少我认为这是 Swift 3 中的选择器格式。我还在习惯 Swift 选择器语法。

Answer 4

对于 Swift 3 适配，添加目标时有两个主要变化。

1. 将您的 selector 更改为

   buttonContents.addTarget(self, action: #selector(BottomMenu.onClick(_:)), for: .touchUpInside)
   

2. 在方法中添加下划线

   func onClick(_ sender: UIButton!){
   

澄清一下：

class BottomMenu : NSObject{

    //Container view
    var bottomView: UIView!    

    //Button
    var buttonContents : UIButton!


    init(bottomView : UIView) {
        super.init()
        self.bottomView = bottomView        

        buttonContents = UIButton(frame: getFrame(index: 0))    
        buttonContents.backgroundColor = UIColor.blue //To see where to click on the screen
        bottomView.addSubview(buttonContents)

        buttonContents.addTarget(self, action: #selector(self.onClick(_:)), for: .touchUpInside)
    }

    func getFrame(index : CGFloat!) -> CGRect{
        let screenW = UIScreen.main.bounds.width
        return CGRect(x: (screenW/3) * index,
                           y: 0,
                           width: screenW/3,
                           height: self.bottomView.frame.size.height)
    }    
    func onClick(_ sender: UIButton!){
        NSLog("click")
    }

}