Question

我已经测试了以下代码，但是当我给它约束时，它会变成一个小圆圈：

 override func drawRect(rect: CGRect) {
var path = UIBezierPath(ovalInRect: rect)
fillColor.setFill()
path.fill()

//set up the width and height variables
//for the horizontal stroke
let plusHeight:CGFloat = 300.0
let plusWidth:CGFloat = 450.0

//create the path
var plusPath = UIBezierPath()

//set the path's line width to the height of the stroke
plusPath.lineWidth = plusHeight

//move the initial point of the path
//to the start of the horizontal stroke
plusPath.moveToPoint(CGPoint(
  x:self.bounds.width/2 - plusWidth/2 + 0.5,
  y:self.bounds.height/2 + 0.5))

//add a point to the path at the end of the stroke
plusPath.addLineToPoint(CGPoint(
  x:self.bounds.width/2 + plusWidth/2 + 0.5,
  y:self.bounds.height/2 + 0.5))

}

Answer 1

根据需要更改radius和fillColor。：）

import Foundation
import UIKit

class CircleLayerView: UIView {
    var circleLayer: CAShapeLayer!

    override func draw(_ rect: CGRect) {
        super.draw(rect)
        if circleLayer == nil {
            circleLayer = CAShapeLayer()
            let radius: CGFloat = 150.0
            circleLayer.path = UIBezierPath(roundedRect: CGRect(x: 0, y: 0, width: 2.0 * radius, height: 2.0 * radius), cornerRadius: radius).cgPath
            circleLayer.position = CGPoint(x: self.frame.midX - radius, y: self.frame.midY - radius)
            circleLayer.fillColor = UIColor.blue.cgColor
            self.layer.addSublayer(circleLayer)
        }
    }
}

Answer 2

传递到rect的{{1}}是需要更新的区域，而不是图纸的大小。在您的情况下，您可能只是忽略传入的矩形并将圆圈设置为您想要的大小。

drawRect

Answer 3

基于@picciano和@Huynh_Inc答案的组合，我现在正在做以下事情：

var selectionLayer: CAShapeLayer?

override func drawRect(rect: CGRect) {

    super.drawRect(rect)

    guard selectionLayer == nil else {
        return
    }

    let layer = CAShapeLayer()

    layer.path = UIBezierPath(ovalInRect: rect).CGPath
    layer.fillColor = myCoolColor.CGColor

    self.layer.addSublayer(layer)

    selectionLayer = layer   
}

如何使用CALayer创建一个圆圈？

3 个答案: