带有UIBezierPath的CAShapeLayer

Question

我想在这样的UITableView单元格中显示三角形视图.

我设法使用吹码完成了这个.

import UIKit

class TriangleView: UIView {

    override func drawRect(rect: CGRect) {
        let width = self.layer.frame.width
        let height = self.layer.frame.height

        let path = CGPathCreateMutable()
        CGPathMoveToPoint(path, nil, 0, 0)
        CGPathAddLineToPoint(path, nil, width, 0)
        CGPathAddLineToPoint(path, nil, 0, height)
        CGPathAddLineToPoint(path, nil, 0, 0)
        CGPathCloseSubpath(path)

        let mask = CAShapeLayer()
        mask.frame = self.layer.bounds
        mask.path = path

        self.layer.mask = mask

        let shape = CAShapeLayer()
        shape.frame = self.bounds
        shape.path = path
        shape.fillColor = UIColor.clearColor().CGColor

        self.layer.insertSublayer(shape, atIndex: 0)
    }
}

当我在UIViews中搜索如何创建形状时,我发现你可以使用UIBezierPath它来做同样的事情.所以我尝试使用相同的东西复制UIBezierPath.

let path = UIBezierPath()
path.moveToPoint(CGPoint(x: 0, y: 0))
path.moveToPoint(CGPoint(x: width, y: 0))
path.moveToPoint(CGPoint(x: 0, y: height))
path.moveToPoint(CGPoint(x: 0, y: 0))
path.closePath()

let mask = CAShapeLayer()
mask.frame = self.bounds
mask.path = path.CGPath

self.layer.mask = mask

let shape = CAShapeLayer()
shape.frame = self.bounds
shape.path = path.CGPath
shape.fillColor = UIColor.clearColor().CGColor

self.layer.insertSublayer(shape, atIndex: 0)

但这根本行不通.没有形状显示出来.

我是否需要做额外的工作以使其正常工作？

Answer 1

你正在努力使它变得更加困难.您只需要添加带路径的形状图层,然后设置该fillColor图层.你的代码不起作用的主要原因是因为你使用的moveToPoint是所有行而不是addLineToPoint除了第一行之外的所有行.

class TriangleView: UIView {

    required init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        let path = UIBezierPath()
        path.moveToPoint(CGPoint(x: 0, y: 0))
        path.addLineToPoint(CGPoint(x: frame.size.width, y: 0))
        path.addLineToPoint(CGPoint(x: 0, y: frame.size.height))
        path.closePath()

        let shape = CAShapeLayer()
        shape.frame = self.bounds
        shape.path = path.CGPath
        shape.fillColor = UIColor.blueColor().CGColor
        self.layer.addSublayer(shape)
    }
}