如何使CAShapeLayer快速处理约束？ [英] How to get CAShapeLayer to work with constraints with swift?

问题描述

我在viewdidload中得到了

i got this in viewdidload

rectShape1 = CAShapeLayer()

rectShape1.fillColor = UIColor.blueColor().CGColor
rectShape1.path = UIBezierPath(roundedRect: rectShape1.bounds, byRoundingCorners: .BottomLeft | .TopRight, cornerRadii: CGSize(width: 20, height: 20)).CGPath
redview.layer.addSublayer(rectShape1)


var constTop = NSLayoutConstraint(item: redview, attribute: NSLayoutAttribute.CenterX, relatedBy: NSLayoutRelation.Equal, toItem: view, attribute: NSLayoutAttribute.CenterX, multiplier: 1, constant: 0)
view.addConstraint(constTop)

var constH = NSLayoutConstraint(item: redview, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: 50)
redview.addConstraint(constH)

var constW = NSLayoutConstraint(item: redview, attribute: NSLayoutAttribute.Width, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: 50)
redview.addConstraint(constW)

constH = NSLayoutConstraint(item: redview, attribute: NSLayoutAttribute.CenterY, relatedBy: NSLayoutRelation.Equal, toItem: view, attribute: NSLayoutAttribute.CenterY, multiplier: 1, constant: 0)
view.addConstraint(constH)
rectShape1.frame = redview.bounds

，这在didlayoutsubviews中

and this in didlayoutsubviews

            self.rectShape1.frame = self.redview.bounds

我在gradientLayer上也有类似的东西，但我工作得很好，

i have similar stuff with gradientLayer and i works fine, any suggestions?

推荐答案

问题是 rectShape1.bounds.size 创建贝塞尔曲线路径时的值为{0,0}。从 viewDidLoad 中删除​​创建路径的行，并在 viewDidLayoutSubviews ，

The problem is that rectShape1.bounds.size is {0,0} at the time you create the bezier path. Remove the line where you create the path from viewDidLoad, and move it to after you set the frame in viewDidLayoutSubviews,

override func viewDidLayoutSubviews() {
        self.rectShape1.frame = self.redview.bounds
        rectShape1.path = UIBezierPath(roundedRect: rectShape1.bounds, byRoundingCorners: .BottomLeft | .TopRight, cornerRadii: CGSize(width: 20, height: 20)).CGPath
    }

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