快速画一条全宽的虚线？

Question

我正在尝试以编程方式创建虚线。然而，这条线并没有一直穿过屏幕。

我一直在使用这个SO answer 来帮助我构建我的虚线。这是我得到的输出。

这是我的代码

extension UIView{
    func addDashedBorder() {
        //Create a CAShapeLayer
        let shapeLayer = CAShapeLayer()
        shapeLayer.strokeColor = UIColor.red.cgColor
        shapeLayer.lineWidth = 2
        // passing an array with the values [2,3] sets a dash pattern that alternates between a 2-user-space-unit-long painted segment and a 3-user-space-unit-long unpainted segment
        shapeLayer.lineDashPattern = [2,3]

        let path = CGMutablePath()
        path.addLines(between: [CGPoint(x: 0, y: 0),
                                CGPoint(x: self.frame.width, y: 0)])
        shapeLayer.path = path
        layer.addSublayer(shapeLayer)


    }
}

如何修复我的代码以使该行跨越整个屏幕？

Answer 1

给CAShapeLayer框架

extension UIView{
    func addDashedBorder() {
        //Create a CAShapeLayer
        let shapeLayer = CAShapeLayer()
        shapeLayer.frame = self.bounds
        shapeLayer.strokeColor = UIColor.red.cgColor
        shapeLayer.lineWidth = 2
        // passing an array with the values [2,3] sets a dash pattern that alternates between a 2-user-space-unit-long painted segment and a 3-user-space-unit-long unpainted segment
        shapeLayer.lineDashPattern = [2,3]

        let size = shapeLayer.frame.size
        let rightTop = CGPoint.zero
        let leftTop = CGPoint(x: size.width, y: 0)
        let leftBottom = CGPoint(x: size.width, y: size.height)
        let rightBottom = CGPoint(x: 0, y: size.height)

        let path = CGMutablePath()
        path.addLines(between: [rightTop, leftTop, rightBottom, rightTop])
        shapeLayer.path = path
        layer.addSublayer(shapeLayer)


    }
}

Answer 2

使用self.bounds.width 而不是self.frame.width。

来自UIView的文档：

框架

框架矩形，描述视图的位置和 superview 的坐标系中的大小。

而：

界限

边界矩形，描述视图的位置和大小 自己的坐标系。