Question

当用户触摸并按住手指在屏幕上时，我使用touchesBegan在屏幕上添加视图

请参见下面的示例

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        if let touch = touches.first {
            let location = touch.location(in: view)
            let dot = CustomTouch(frame: CGRect(x: location.x, y: location.y, width: 80, height: 80))
            dot.backgroundColor = randomColors[0]
            self.view.addSubview(dot)
        }
    }

我想检测用户何时从屏幕上抬起手指，然后删除在该位置添加的视图。我想要一些有关如何实现这一目标的想法

Answer 1

为添加的视图添加属性，而不是动态创建，然后如果在touchesEnded上存在，则将其删除：

var dot: CustomTouch?

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    if let touch = touches.first {
        let location = touch.location(in: view)
        dot = CustomTouch(frame: CGRect(x: location.x, y: location.y, width: 80, height: 80))
        dot.backgroundColor = randomColors[0]
        self.view.addSubview(dot)
    }
}

override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    dot?.removeFromSuperview()
}

Answer 2

这为我完成了工作： 1）创建一个字典来存储每个为特定触摸创建的“ CustomTouch” 2）当touchesEnded结束时，我将删除该键（UITouch）的对象

调用touchesEnded时删除视图

2 个答案: