touchesEnded 后如何使用 touchesBegan答案

【问题标题】：How to use touchesBegan again after touchesEndedtouchesEnded 后如何使用 touchesBegan
【发布时间】：2019-11-10 14:20:35
【问题描述】：

我的代码结果是在我已经画线之后，它会检测到正确或错误的位置并显示结果，但是在我已经画完之后它会突然显示结果。我希望它在绘制超过 1 条线后显示结果。我该怎么办？

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    super.touchesBegan(touches, with: event)
    let touch = touches.first
    swiped = false
    lastPoint = touch?.location(in: self)
    firstPoint = lastPoint
}


override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
    super.touchesMoved(touches, with: event)
    if let touch = touches.first {
        swiped = true
        currentPoint = touch.location(in: self)
        drawShapeLayer(from: lastPoint, to: currentPoint)
        lastPoint = currentPoint
    }
}

override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    super.touchesEnded(touches, with: event)
    if !swiped {
        drawShapeLayer(from: lastPoint, to: lastPoint!)
    }


    if  c1.contains(firstPoint) && c3.contains(linePoint) && c2.contains(lastPoint){
        AlertView.instance.showAlert(title: "Hooray!", message: "You made it!", alertType : .success)
    }

    else {
        AlertView.instance.showAlert(title: "Oops!", message: "You've almost got it.", alertType : .failure)
    }
}

【问题讨论】：

标签： ios swift touch draw cgpath

【解决方案1】：

首先，使用 UISwipeGestureRecognizer 可能更容易 https://developer.apple.com/documentation/uikit/uiswipegesturerecognizer

它们抽象出很多东西，并简化了状态和路径之类的东西。

其中一些让我感到困惑

if !swiped {
    drawShapeLayer(from: lastPoint, to: lastPoint!)
}

不应该是这样的

if !swiped {
    let touch = touches.first
    lastPoint = touch?.location(in: self)
    drawShapeLayer(from: firstPoint, to: lastPoint!)
}

也在这个

  if  c1.contains(firstPoint) && c3.contains(linePoint) && c2.contains(lastPoint){
        AlertView.instance.showAlert(title: "Hooray!", message: "You made it!", alertType : .success)
    }

不会有 linePoint != lastPoint 的时候。

除非“drawShapeLayer”改变了这些，在这种情况下你的数据封装有点混乱。

【讨论】：