Question

我的CAShapeLayer未显示。我试图通过循环遍历CGPoints数组来创建一个形状。我需要使用数组或字典，以便稍后添加不同的CGPoints集来创建更复杂的形状。

var shapeLayer = CAShapeLayer()
var color = UIColor.redColor()
var openPath = UIBezierPath()
var closedPath = UIBezierPath()
let points = [CGPoint(x: 30, y: 30), CGPoint(x: 90, y: 30), CGPoint(x: 90, y: 90), CGPoint(x: 90, y: 30), CGPoint(x: 30, y: 30)]
var firstTime = false

override func viewDidLoad()
{
    super.viewDidLoad()
    setOpenPath()
}

func setOpenPath()
{
    for number in points
    {
        if number != points.first
        {
           openPath.addLineToPoint(number)
        }

        if number == points.first
        {
            if firstTime == false
            {
                openPath.moveToPoint(number)
            }
            if firstTime == true
            {
                openPath.addLineToPoint(number)
                setClosePath()
            }
            firstTime = true
        }
    }
}

func setClosePath()
{
    firstTime = false
    closedPath.CGPath = CGPathCreateMutableCopy(openPath.CGPath)
    closedPath.closePath()
    setShapeLayer()
}

func setShapeLayer()
{
    shapeLayer.path = closedPath.CGPath
    shapeLayer.fillColor = UIColor.greenColor().CGColor
    shapeLayer.fillRule = kCAFillRuleNonZero
    self.view.layer.addSublayer(shapeLayer)
}

如果我用下面的代码替换setOpenPath（）中的代码，脚本工作正常。

openPath.moveToPoint(CGPoint(x: 30, y: 30))
openPath.addLineToPoint(CGPoint(x: 90, y: 30))
openPath.addLineToPoint(CGPoint(x: 90, y: 90))
openPath.addLineToPoint(CGPoint(x: 30, y: 90))
openPath.addLineToPoint(CGPoint(x: 30, y: 30))
setClosePath()

Answer 1

你的点在points数组中搞砸了。与下面的代码相比，索引3处的元素是错误的。它不会产生封闭的路径。

是正确的要素

let points = [CGPoint(x: 30, y: 30), CGPoint(x: 90, y: 30), CGPoint(x: 90, y: 90), CGPoint(x: 30, y: 90), CGPoint(x: 30, y: 30)]

还可以使用其他条件并像这样简化循环

func setOpenPath()
{
    firstTime = true
    for number in points
    {
        if number != points.first
        {
            openPath.addLineToPoint(number)
        }
        else
        {
            if firstTime
            {
                openPath.moveToPoint(number)
            }
            else
            {
                openPath.addLineToPoint(number)
                setClosePath()
            }
            firstTime = false
        }
    }
}

CAShapeLayer形状不显示

1 个答案: