Swift Playgrounds 中的 UIGestureRecognizer

Posted 2023-02-24

【中文标题】Swift Playgrounds 中的 UIGestureRecognizer

【英文标题】：UIGestureRecognizer in Swift Playgrounds

【发布时间】：2017-03-31 23:45:10

【问题描述】：

我正在尝试将 UIGestureRecognizer 集成到我的快速操场中，这样无论我在操场上点击什么，我的精灵都会到达那个点。我什么都试过了！观看无数的 youtube 视频，并继续堆栈溢出以寻求答案，但每个人都从创建一个名为 view 的类开始，它是一个 UIView，并且在他们的代码中他们一直提到“self”。相反，我创建了一个名为“view”的变量，它是一个 SKView。我尝试获取他们的部分代码，将其放入我的代码中并进行更改，但它不起作用。这是我目前所做的工作。

view.addGestureRecognizer(UIGestureRecognizer(target: view, action:  #selector(handleTap(sender:))))

func handleTap(sender: UITapGestureRecognizer) 
        player.position = sender.location(in: view)

我的 Playground 一直告诉我我正在使用未解析的标识符 'handleTap(sender:)'

【参考方案1】：

在 Playground 中具有不同手势识别器状态的 UIGestureRecognizer 示例

swift3+

import UIKit
import PlaygroundSupport

class ViewController : UIViewController 

    var yellowView: UIView!
    var redView: UIView!
    var yellowViewOrigin: CGPoint!

    override func loadView() 

        // UI

        let view = UIView()
        view.backgroundColor = .white

        yellowView = UIView()
        yellowView.backgroundColor = .yellow
        view.addSubview(yellowView)

        redView = UIView()
        redView.backgroundColor = .red
        view.addSubview(redView)

        // Layout
        redView.translatesAutoresizingMaskIntoConstraints = false
        yellowView.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            yellowView.topAnchor.constraint(equalTo: view.topAnchor, constant: 20.0),
            yellowView.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 20.0),
            yellowView.heightAnchor.constraint(equalToConstant: 80.0),
            yellowView.widthAnchor.constraint(equalToConstant: 80.0),

            redView.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -20.0),
            redView.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -20.0),
            redView.heightAnchor.constraint(equalToConstant: 80.0),
            redView.widthAnchor.constraint(equalToConstant: 80.0)

            ])

        self.view = view
    

    override func viewDidLoad() 
        super.viewDidLoad()
        let pan = UIPanGestureRecognizer(target: self, action: #selector(self.handlePanGesture(_:)))
        yellowView.addGestureRecognizer(pan)
        yellowViewOrigin = yellowView.frame.origin
        view.bringSubview(toFront: yellowView)
    

    @objc func handlePanGesture(_ sender: UIPanGestureRecognizer) 
        let targetView = sender.view!
        let translation = sender.translation(in: view)

        switch sender.state 
        case .began,.changed:
            targetView.center = CGPoint(x: targetView.center.x + translation.x
                ,y: targetView.center.y + translation.y)
            sender.setTranslation(CGPoint.zero, in: view)
        case .ended:
            if targetView.frame.intersects(redView.frame)
                UIView.animate(withDuration: 0.3) 
                    targetView.alpha = 0.0
                

            
            else
            UIView.animate(withDuration: 0.3) 
                targetView.frame.origin = self.yellowViewOrigin
            
            
            break
        default:
            break
        

    


PlaygroundPage.current.liveView = ViewController()

【参考方案2】：

我认为您需要在函数声明前添加@objc 标记，以便handleTap 对#selector 可见。

@objc func handleTap(sender: UITapGestureRecognizer) 
    player.position = sender.location(in: view) 

【讨论】：

这不起作用，因为我的项目不在类中

【参考方案3】：

func handleTap 必须从您的 view 类型中调用。

请尝试将其添加到 SKView 扩展中：

    extension SKView 
        func handleTap(sender: UITapGestureRecognizer) 
                player.position = sender.location(in: view)