如何制作三角形 UIView？答案

【问题标题】：How can I make a triangular UIView?如何制作三角形 UIView？
【发布时间】：2017-03-18 23:24:23
【问题描述】：

我是 Swift 新手。我的应用程序中有一个常规的矩形 UIView，我试图将其设为三角形，以便用户可以在边界内绘制。

有什么建议吗？我正在使用 UIKit 并希望避免使用 SpriteKit。

谢谢！

【问题讨论】：

使用 UIBezierPath。
stackoverflow.com/questions/30650343/triangle-uiview-swift回答了同样的问题

标签： swift xcode uiview uikit

【解决方案1】：

Result triangles

swift5中的代码

//TriangleView

extension UIView {

    func setRightTriangle(targetView:UIView?){
        let heightWidth = targetView!.frame.size.width //you can use triangleView.frame.size.height
        let path = CGMutablePath()

        path.move(to: CGPoint(x: heightWidth/2, y: 0))
        path.addLine(to: CGPoint(x:heightWidth, y: heightWidth/2))
        path.addLine(to: CGPoint(x:heightWidth/2, y:heightWidth))
        path.addLine(to: CGPoint(x:heightWidth/2, y:0))

        let shape = CAShapeLayer()
        shape.path = path
        shape.fillColor = UIColor.blue.cgColor

        targetView!.layer.insertSublayer(shape, at: 0)
    }

    func setLeftTriangle(targetView:UIView?){
        let heightWidth = targetView!.frame.size.width
        let path = CGMutablePath()

        path.move(to: CGPoint(x: heightWidth/2, y: 0))
        path.addLine(to: CGPoint(x:0, y: heightWidth/2))
        path.addLine(to: CGPoint(x:heightWidth/2, y:heightWidth))
        path.addLine(to: CGPoint(x:heightWidth/2, y:0))

        let shape = CAShapeLayer()
        shape.path = path
        shape.fillColor = UIColor.blue.cgColor

        targetView!.layer.insertSublayer(shape, at: 0)
    }

    func setUpTriangle(targetView:UIView?){
     let heightWidth = targetView!.frame.size.width
        let path = CGMutablePath()

        path.move(to: CGPoint(x: 0, y: heightWidth))
        path.addLine(to: CGPoint(x:heightWidth/2, y: heightWidth/2))
        path.addLine(to: CGPoint(x:heightWidth, y:heightWidth))
        path.addLine(to: CGPoint(x:0, y:heightWidth))

        let shape = CAShapeLayer()
        shape.path = path
        shape.fillColor = UIColor.blue.cgColor

        targetView!.layer.insertSublayer(shape, at: 0)
    }

    func setDownTriangle(targetView:UIView?){
        let heightWidth = targetView!.frame.size.width
        let path = CGMutablePath()

        path.move(to: CGPoint(x: 0, y: 0))
        path.addLine(to: CGPoint(x:heightWidth/2, y: heightWidth/2))
        path.addLine(to: CGPoint(x:heightWidth, y:0))
        path.addLine(to: CGPoint(x:0, y:0))

        let shape = CAShapeLayer()
        shape.path = path
        shape.fillColor = UIColor.blue.cgColor

        targetView!.layer.insertSublayer(shape, at: 0)
    }
}

【讨论】：