ios - 带有 UIBezierPath 的 CAShapeLayer

Question

我想像这样在 UITableView 单元格中显示三角形 View 。

我设法使用打击代码完成了此任务。

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)
    }
}

当我在搜索如何在 UIViews 中创建形状时，我发现您可以使用 UIBezierPath 来做同样的事情。所以我尝试使用 UIBezierPath 复制相同的东西。

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。没有显示任何形状。

我需要做任何额外的事情才能让它正常工作吗？

Answer 1

你让这件事变得比它需要的更难。您只需要添加一个带有路径的形状图层，并设置该图层的fillColor。但是，您的代码不起作用的主要原因是因为您对所有行都使用 moveToPoint 而不是对第一行以外的所有行使用 addLineToPoint 。

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)
    }
}