画一条线来连接两个圆圈

Question

我正在构建一个自定义的用户界面输入，让用户通过一条线连接两个圆圈。

这就是原型的样子

我想知道怎么画直线？ UIViews？ SpriteKit？或者什么？

Answer 1

您应该使用UIBezierPath()和CAShapeLayer()。

这个功能可以解决这个问题：

func drawLineFromPoint(point1:CGPoint, point2:CGPoint) {
    let path = UIBezierPath()
    path.moveToPoint(point1)
    path.addLineToPoint(point2)

    let shapeLayer = CAShapeLayer()
    shapeLayer.path = path.CGPath
    shapeLayer.strokeColor = UIColor.greenColor().CGColor
    shapeLayer.lineWidth = 1
    shapeLayer.fillColor = UIColor.clearColor().CGColor

    self.view.layer.addSublayer(shapeLayer)
}

Answer 2

没有缓存版本：

class LineView:UIView {

    var startP: CGPoint?
    var endP: CGPoint?

    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
        let touch = touches.first
        let location = touch?.locationInView(self);

        //do some matching here...

        self.startP = location
    }

    override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
        let touch = touches.first
        let location = touch?.locationInView(self);
        self.endP = location
        self.setNeedsDisplay()
    }

    override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
        let touch = touches.first
        let location = touch?.locationInView(self);

        //do some matching here...

        self.endP = location
        self.setNeedsDisplay()
    }

    override func drawRect(rect: CGRect) {
        let context = UIGraphicsGetCurrentContext()

        if let start = self.startP {
            if let end = self.endP {
                CGContextMoveToPoint(context, start.x, start.y)
                CGContextAddLineToPoint(context, end.x, end.y)
                CGContextSetStrokeColorWithColor(context, UIColor.blueColor().CGColor)
                CGContextStrokePath(context)
            }
        }
    }
}