ios - 如何在 UIView 上正确设置围绕圆的对象

Question

我已经编写了一些代码来围绕位于自定义 View 中心的圆圈放置对象，但它并没有完全围绕圆圈。我不知道代码哪里错了。

代码如下:

func createObjectsAroundCircle() {

    let center = CGPointMake(bounds.width/2 ,bounds.height/2)
    let radius : CGFloat = 100
    let count = 20

    var angle = CGFloat(2 * M_PI)
    let step = CGFloat(2 * M_PI) / CGFloat(count)

    let circlePath = UIBezierPath(arcCenter: center, radius: radius, startAngle: CGFloat(0), endAngle:CGFloat(M_PI * 2), clockwise: true)

    let shapeLayer = CAShapeLayer()
    shapeLayer.path = circlePath.CGPath

    shapeLayer.fillColor = UIColor.clearColor().CGColor
    shapeLayer.strokeColor = UIColor.redColor().CGColor
    shapeLayer.lineWidth = 3.0

    self.layer.addSublayer(shapeLayer)

    // set objects around circle
    for var index = 0; index < count ; index++ {
        let x = cos(angle) * radius + center.x
        let y = sin(angle) * radius + center.y

        let label = UILabel()
        label.text = "\(index)"
        label.frame.origin.x = x
        label.frame.origin.y = y
        label.font = UIFont(name: "Arial", size: 20)
        label.textColor = UIColor.blackColor()
        label.sizeToFit()

        self.addSubview(label)
        angle += step 
    }
}

Answer 1

您的代码运行正常，只是计算逻辑错误。您应该尝试设置 label.center 而不是 label.frame.origin，或者

let label = UILabel()
label.text = "\(index)"
label.font = UIFont(name: "Arial", size: 20)
label.textColor = UIColor.blackColor()
label.sizeToFit()
label.frame.origin.x = x - label.frame.midX
label.frame.origin.y = y - label.frame.midY

请记住在更改框架或设置标签的 center 之前使用 sizeToFit()。祝你好运!