自定义UIGestureRecognizer后按钮失效，如何实现视图与按钮事件共存？

嘿，我帮你搞定这个手势和按钮冲突的问题～

问题根源分析 #

你的自定义SingleTouchDownGestureRecognizer目前有两个核心问题：

1. 默认cancelsTouchesInView = true，当手势被标记为.recognized后，系统会直接拦截后续的触摸事件（比如touchesEnded），导致按钮收不到完整的触摸流程，自然触发不了Touch Up Inside事件。
2. 没有判断触摸区域是否属于子控件（按钮），导致按钮上的触摸也会触发视图的手势响应，不符合你“触摸按钮时视图无需响应”的需求。

解决方案&代码修改 #

我们从两个方向调整代码就能解决问题：

1. 允许触摸事件继续传递给子控件

在添加手势时，把cancelsTouchesInView设为false，这样即使视图的手势被识别，后续的触摸事件依然能传递给按钮：

let t = SingleTouchDownGestureRecognizer(target: self, action: #selector(handleTap(sender:)))
t.cancelsTouchesInView = false // 关键设置！
self.view.addGestureRecognizer(t)

2. 在自定义手势中过滤按钮区域的触摸

在touchesBegan方法里，先判断触摸的目标视图是否是UIControl（按钮是它的子类），如果是直接将手势状态设为.failed，让事件正常传递给按钮，同时视图的手势不响应：

class SingleTouchDownGestureRecognizer: UIGestureRecognizer {
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent) {
        guard let touch = touches.first else {
            state = .failed
            return
        }
        
        // 触摸的是按钮等UIControl控件，直接让手势失败
        if let _ = touch.view as? UIControl {
            state = .failed
            return
        }
        
        if state == .possible {
            state = .recognized
        }
    }
    
    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent) {
        state = .failed
    }
    
    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent) {
        state = .failed
    }
}

完整修改后的代码 #

import UIKit
import UIKit.UIGestureRecognizerSubclass

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        let t = SingleTouchDownGestureRecognizer(target: self, action: #selector(handleTap(sender:)))
        t.cancelsTouchesInView = false // 允许后续触摸事件传递给子控件
        self.view.addGestureRecognizer(t)
    }
    
    @objc func handleTap(sender: UITapGestureRecognizer? = nil) {
        self.view.backgroundColor = #colorLiteral(red: 0.2392156869, green: 0.6745098233, blue: 0.9686274529, alpha: 1)
        UIView.animate(withDuration: 1) {
            self.view.backgroundColor = #colorLiteral(red: 1, green: 1, blue: 1, alpha: 1)
        }
    }
    
    @IBAction func testBtnPressed(_ sender: Any) {
        print("testBtnPressed!")
    }
}

class SingleTouchDownGestureRecognizer: UIGestureRecognizer {
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent) {
        guard let touch = touches.first else {
            state = .failed
            return
        }
        
        // 过滤按钮等UIControl的触摸
        if let _ = touch.view as? UIControl {
            state = .failed
            return
        }
        
        if state == .possible {
            state = .recognized
        }
    }
    
    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent) {
        state = .failed
    }
    
    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent) {
        state = .failed
    }
}

现在测试一下：

• 触摸视图空白区域：视图会正常触发handleTap，背景色变化；
• 触摸按钮：按钮能完整响应Touch Up Inside事件，打印testBtnPressed!，同时视图不会有任何响应。

内容的提问来源于stack exchange，提问作者skyIsCoding