让UIScrollView放弃UITouch

Question

我有一个绘图应用程序，它的画布比手机屏幕大小。我想实现两个手指滚动，一个手指作画。到目前为止，我可以使滚动工作正常，但当涉及到绘制时，线开始，然后绘制的视图失去了对触摸的控制，从而只绘制了线的第一部分。我认为scrollview收回了控制权。点可以画得很好。

这是我的子类UIScrollView

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    guard let touches = event?.touches(for: self) else { return }
    if touches.count < 2 {
        self.next?.touchesBegan(touches, with: event)
    } else {
        super.touchesBegan(touches, with: event)
    }
}

override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    guard let touches = event?.touches(for: self) else { return }
    if touches.count < 2 {
        self.next?.touchesEnded(touches, with: event)
    } else {
        super.touchesEnded(touches, with: event)
    }
}

override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
    guard let touches = event?.touches(for: self) else { return }
    if touches.count < 2 {
        self.next?.touchesMoved(touches, with: event)
    } else {
        super.touchesMoved(touches, with: event)
    }
}

override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
    guard let touches = event?.touches(for: self) else { return }
    if touches.count < 2 {
        self.next?.touchesCancelled(touches, with: event)
    } else {
        super.touchesCancelled(touches, with: event)
    }
}

override func touchesShouldCancel(in view: UIView) -> Bool {
    if (type(of: view)) == UIScrollView.self {
        return true
    }
    return false
}

Answer 1

您将需要一个连接到您的ScrollerView的长按手势识别器，设置为最小持续时间0秒，还可以识别only 1 Touch和Cancel touches in view选项激活。

您可以在Interface Builder上的Attributes Inspector下找到所有这些选项。

请稍微调整一下容差设置以微调结果。