我如何在iOS Swift中画一个圆？_Ios_Swift

我如何在iOS Swift中画一个圆？

ios swift

我如何在iOS Swift中画一个圆？,ios,swift,Ios,Swift,这就是我现在所拥有的，但这显然不是正确的方式最简单的方法是什么？如果要使用UIView绘制它，则需要绘制高度或宽度的半径所以只要改变一下： let block = UIView(frame: CGRectMake(cellWidth-25, cellHeight/2-8, 16, 16)) block.backgroundColor = UIColor(netHex: 0xff3b30) block.layer.cornerRadius = 9 block.clipsToBounds = t

这就是我现在所拥有的，但这显然不是正确的方式

最简单的方法是什么？

如果要使用UIView绘制它，则需要绘制高度或宽度的半径

所以只要改变一下：

let block = UIView(frame: CGRectMake(cellWidth-25, cellHeight/2-8, 16, 16))
block.backgroundColor = UIColor(netHex: 0xff3b30)
block.layer.cornerRadius = 9
block.clipsToBounds = true

致：

但是，您需要使高度和宽度相同。如果您想使用coregraphics，则需要执行以下操作：

block.layer.cornerRadius = block.frame.width / 2

警告！这是一个错误的解决方案。在
drawRect
方法中无限添加图层（每次绘制视图时）。决不能在
drawRect
方法中添加层。改用
layoutSubview
。

您可以使用此（Swift 3.0+）绘制一个圆：

let circlePath=UIBezierPath（弧心：CGPoint（x:100，y:100），半径：CGFloat（20），星形缠结：CGFloat（0），端角：CGFloat（Double.pi*2），顺时针：true）
设shapeLayer=CAShapeLayer（）
shapeLayer.path=circlePath.cgPath
//更改填充颜色
shapeLayer.fillColor=UIColor.clear.cgColor
//您可以更改笔划颜色
shapeLayer.strokeColor=UIColor.red.cgColor
//您可以更改线宽
shapeLayer.lineWidth=3.0
view.layer.addSublayer（shapeLayer）

使用您发布的代码，您正在裁剪

ui视图的角，而不是在视图中添加圆

下面是使用该方法的完整示例：
///一个特殊的UIView，显示为一圈颜色
类环：UIView{
重写func drawRect（rect:CGRect）{
图纸配件侧视图（）
}
内部函数DrawringFittingSideView（）->（）{
let halfSize:CGFloat=min（bounds.size.width/2，bounds.size.height/2）
让desiredLineWidth:CGFloat=1//指定所需的值
设circlePath=UIBezierPath(
弧中心：CGPoint（x:半尺寸，y:半尺寸），
半径：CGFloat（半尺寸-（所需线宽/2）），
startAngle:CGFloat（0），
端角：CGFloat（M_PI*2），
顺时针：正确）
设shapeLayer=CAShapeLayer（）
shapeLayer.path=circlePath.CGPath
shapeLayer.fillColor=UIColor.clearColor（）.CGColor
shapeLayer.strokeColor=UIColor.redColor（）.CGColor
shapeLayer.lineWidth=所需线宽
layer.addSublayer（shapeLayer）
}
}



请注意，这里有一个非常方便的电话：
let circlePath=UIBezierPath（ovalInRect:rect）
它完成了制作路径的所有工作。（别忘了为线条粗细插入它，使用CGRectInset
也非常容易）
内部函数绘图装置侧视图（rect:CGRect）{
让desiredLineWidth:CGFloat=4//指定所需的值
设hw:CGFloat=desiredLineWidth/2
设circlePath=UIBezierPath（ovalInRect:CGRectInset（rect，hw，hw））
设shapeLayer=CAShapeLayer（）
shapeLayer.path=circlePath.CGPath
shapeLayer.fillColor=UIColor.clearColor（）.CGColor
shapeLayer.strokeColor=UIColor.redColor（）.CGColor
shapeLayer.lineWidth=所需线宽
layer.addSublayer（shapeLayer）
}



在Swift的实践中，您肯定会使用@IBDesignable
和@IBInspectable
。使用这些，您实际上可以在故事板中查看和更改渲染
如您所见，它实际上向情节提要上的检查器添加了新功能，您可以在情节提要上更改这些功能：


最后，请注意，如果您有一个UIView
（它是方形的，并且在故事板中设置为红色），并且您只想将它变成一个红色圆圈，那么您可以执行以下操作：
/// A dot with a border, which you can control completely in Storyboard
@IBDesignable class Dot: UIView {

    @IBInspectable var mainColor: UIColor = UIColor.blueColor() {
        didSet { 
             print("mainColor was set here")
        }
    }

    @IBInspectable var ringColor: UIColor = UIColor.orangeColor() {
         didSet {
             print("bColor was set here") 
        }
    }

    @IBInspectable var ringThickness: CGFloat = 4 {
        didSet { 
            print("ringThickness was set here")
        }
    }
    
    @IBInspectable var isSelected: Bool = true
    
    override func drawRect(rect: CGRect) {
        let dotPath = UIBezierPath(ovalInRect:rect)
        let shapeLayer = CAShapeLayer()
        shapeLayer.path = dotPath.CGPath
        shapeLayer.fillColor = mainColor.CGColor
        layer.addSublayer(shapeLayer)
        
        if (isSelected) { 
            drawRingFittingInsideView(rect)
        }
    }
    
    internal func drawRingFittingInsideView(rect: CGRect) {
        let hw:CGFloat = ringThickness/2
        let circlePath = UIBezierPath(ovalInRect: CGRectInset(rect,hw,hw) )
        
        let shapeLayer = CAShapeLayer()
        shapeLayer.path = circlePath.CGPath
        shapeLayer.fillColor = UIColor.clearColor().CGColor
        shapeLayer.strokeColor = ringColor.CGColor
        shapeLayer.lineWidth = ringThickness
        layer.addSublayer(shapeLayer)
    }
}

import UIKit

@IBDesignable
class DrawCircles: UIView {

    override init(frame: CGRect) {
        super.init(frame: frame)
    }

    required public init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    override func draw(_ rect: CGRect) {

        guard let context = UIGraphicsGetCurrentContext() else {
            print("could not get graphics context")
            return
        }

        context.setLineWidth(2)

        context.setStrokeColor(UIColor.blue.cgColor)

        context.addEllipse(in: CGRect(x: 30, y: 30, width: 50.0, height: 50.0))

        context.strokePath()

        context.setStrokeColor(UIColor.red.cgColor)

        context.beginPath() // this prevents a straight line being drawn from the current point to the arc

        context.addArc(center: CGPoint(x:100, y: 100), radius: 20, startAngle: 0, endAngle: 2.0*CGFloat.pi, clockwise: false)

        context.strokePath()
    }
}

更新@Dario针对Xcode 8.2.2、Swift 3.x的代码方法。请注意，在情节提要中，将背景颜色设置为“清除”，以避免方形视图中出现黑色背景：
// Makes a UIView into a circular dot of color
class Dot: UIView {
    override func layoutSubviews() {
        layer.cornerRadius = bounds.size.width/2
    }
}

如果要控制起点和终点角度：
import UIKit
@IBDesignable
class Dot:UIView
{
    @IBInspectable var mainColor: UIColor = UIColor.clear
        {
        didSet { print("mainColor was set here") }
    }
    @IBInspectable var ringColor: UIColor = UIColor.clear
        {
        didSet { print("bColor was set here") }
    }
    @IBInspectable var ringThickness: CGFloat = 4
        {
        didSet { print("ringThickness was set here") }
    }


    @IBInspectable var isSelected: Bool = true

    override func draw(_ rect: CGRect)
    {

        let dotPath = UIBezierPath(ovalIn: rect)
        let shapeLayer = CAShapeLayer()
        shapeLayer.path = dotPath.cgPath
        shapeLayer.fillColor = mainColor.cgColor
        layer.addSublayer(shapeLayer)

        if (isSelected) { drawRingFittingInsideView(rect: rect) }
    }

    internal func drawRingFittingInsideView(rect: CGRect)->()
    {
        let hw:CGFloat = ringThickness/2
        let circlePath = UIBezierPath(ovalIn: rect.insetBy(dx: hw,dy: hw) )

        let shapeLayer = CAShapeLayer()
        shapeLayer.path = circlePath.cgPath
        shapeLayer.fillColor = UIColor.clear.cgColor
        shapeLayer.strokeColor = ringColor.cgColor
        shapeLayer.lineWidth = ringThickness
        layer.addSublayer(shapeLayer)
    }
}

创建一个类UIView，并将此代码分配给它，使其成为一个简单的圆
import UIKit
@IBDesignable
class Dot:UIView
{
    @IBInspectable var mainColor: UIColor = UIColor.clear
        {
        didSet { print("mainColor was set here") }
    }
    @IBInspectable var ringColor: UIColor = UIColor.clear
        {
        didSet { print("bColor was set here") }
    }
    @IBInspectable var ringThickness: CGFloat = 4
        {
        didSet { print("ringThickness was set here") }
    }


    @IBInspectable var isSelected: Bool = true

    override func draw(_ rect: CGRect)
    {

        let dotPath = UIBezierPath(ovalIn: rect)
        let shapeLayer = CAShapeLayer()
        shapeLayer.path = dotPath.cgPath
        shapeLayer.fillColor = mainColor.cgColor
        layer.addSublayer(shapeLayer)

        if (isSelected) { drawRingFittingInsideView(rect: rect) }
    }

    internal func drawRingFittingInsideView(rect: CGRect)->()
    {
        let halfSize:CGFloat = min( bounds.size.width/2, bounds.size.height/2)
        let desiredLineWidth:CGFloat = ringThickness   // your desired value

        let circlePath = UIBezierPath(
            arcCenter: CGPoint(x: halfSize, y: halfSize),
            radius: CGFloat( halfSize - (desiredLineWidth/2) ),
            startAngle: CGFloat(0),
            endAngle:CGFloat(Double.pi),
            clockwise: true)

        let shapeLayer = CAShapeLayer()
        shapeLayer.path = circlePath.cgPath
        shapeLayer.fillColor = UIColor.clear.cgColor
        shapeLayer.strokeColor = ringColor.cgColor
        shapeLayer.lineWidth = ringThickness
        layer.addSublayer(shapeLayer)
    }
}

我发现对于Swift 3，核心图形非常简单：
import UIKit
@IBDesignable
class DRAW: UIView {

    override func draw(_ rect: CGRect) {

        var path = UIBezierPath()
        path = UIBezierPath(ovalIn: CGRect(x: 50, y: 50, width: 100, height: 100))
        UIColor.yellow.setStroke()
        UIColor.red.setFill()
        path.lineWidth = 5
        path.stroke()
        path.fill()


    }


}

加载项视图未加载
if let cgcontext = UIGraphicsGetCurrentContext() {
    cgcontext.strokeEllipse(in: CGRect(x: center.x-diameter/2, y: center.y-diameter/2, width: diameter, height: diameter))
}

Swift 4接受答案的版本：
    //Circle Points

     var CircleLayer   = CAShapeLayer() 

    let center = CGPoint (x: myCircleView.frame.size.width / 2, y: myCircleView.frame.size.height / 2)
    let circleRadius = myCircleView.frame.size.width / 2
    let circlePath = UIBezierPath(arcCenter: center, radius: circleRadius, startAngle: CGFloat(M_PI), endAngle: CGFloat(M_PI * 4), clockwise: true)
    CircleLayer.path = circlePath.cgPath
   CircleLayer.strokeColor = UIColor.red.cgColor
    CircleLayer.fillColor = UIColor.blue.cgColor
    CircleLayer.lineWidth = 8
    CircleLayer.strokeStart = 0
    CircleLayer.strokeEnd  = 1
    Self.View.layer.addSublayer(CircleLayer)

一个简单的函数，使用乘法器百分比在窗框中间画一个圆
@IBDesignable
class CircledDotView: UIView {

    @IBInspectable var mainColor: UIColor = .white {
        didSet { print("mainColor was set here") }
    }
    @IBInspectable var ringColor: UIColor = .black {
        didSet { print("bColor was set here") }
    }
    @IBInspectable var ringThickness: CGFloat = 4 {
        didSet { print("ringThickness was set here") }
    }

    @IBInspectable var isSelected: Bool = true

    override func draw(_ rect: CGRect) {
        let dotPath = UIBezierPath(ovalIn: rect)
        let shapeLayer = CAShapeLayer()
        shapeLayer.path = dotPath.cgPath
        shapeLayer.fillColor = mainColor.cgColor
        layer.addSublayer(shapeLayer)

        if (isSelected) {
            drawRingFittingInsideView(rect: rect)
        }
    }

    internal func drawRingFittingInsideView(rect: CGRect) {
        let hw: CGFloat = ringThickness / 2
        let circlePath = UIBezierPath(ovalIn: rect.insetBy(dx: hw, dy: hw))

        let shapeLayer = CAShapeLayer()
        shapeLayer.path = circlePath.cgPath
        shapeLayer.fillColor = UIColor.clear.cgColor
        shapeLayer.strokeColor = ringColor.cgColor
        shapeLayer.lineWidth = ringThickness
        layer.addSublayer(shapeLayer)
    }
}

一个更简单、资源友好的方法是
/// CGFloat is a multiplicator from self.view.frame.width
func drawCircle(withMultiplicator coefficient: CGFloat) {

    let radius = self.view.frame.width / 2 * coefficient

    let circlePath = UIBezierPath(arcCenter: self.view.center, radius: radius, startAngle: CGFloat(0), endAngle:CGFloat(Double.pi * 2), clockwise: true)
    let shapeLayer = CAShapeLayer()
    shapeLayer.path = circlePath.cgPath

    //change the fill color
    shapeLayer.fillColor = UIColor.clear.cgColor
    shapeLayer.strokeColor = UIColor.darkGray.cgColor
    shapeLayer.lineWidth = 2.0

    view.layer.addSublayer(shapeLayer)
}

使用边框颜色
和边框大小
以及默认的背景
属性，可以定义圆的外观

请注意，要画一个圆圈，视图的高度和宽度必须相等
该代码适用于Swift>=4
和Xcode>=9
 这是我使用Swift 5和核心图形的版本
我创建了一个类来绘制两个圆。第一个圆是使用addEllipse（）
创建的。它将椭圆变成正方形，从而创建一个圆。我发现没有函数addCircle（）
令人惊讶。第二个圆是使用2pi弧度的addArc（）
创建的
import UIKit

@IBDesignable
class CircleDrawView: UIView {

    @IBInspectable var borderColor: UIColor = UIColor.red;

    @IBInspectable var borderSize: CGFloat = 4

    override func draw(_ rect: CGRect)
    {
        layer.borderColor = borderColor.cgColor
        layer.borderWidth = borderSize
        layer.cornerRadius = self.frame.height/2
    }

}

在ViewController的didViewLoad（）
中添加以下内容：
/// A dot with a border, which you can control completely in Storyboard
@IBDesignable class Dot: UIView {

    @IBInspectable var mainColor: UIColor = UIColor.blueColor() {
        didSet { 
             print("mainColor was set here")
        }
    }

    @IBInspectable var ringColor: UIColor = UIColor.orangeColor() {
         didSet {
             print("bColor was set here") 
        }
    }

    @IBInspectable var ringThickness: CGFloat = 4 {
        didSet { 
            print("ringThickness was set here")
        }
    }
    
    @IBInspectable var isSelected: Bool = true
    
    override func drawRect(rect: CGRect) {
        let dotPath = UIBezierPath(ovalInRect:rect)
        let shapeLayer = CAShapeLayer()
        shapeLayer.path = dotPath.CGPath
        shapeLayer.fillColor = mainColor.CGColor
        layer.addSublayer(shapeLayer)
        
        if (isSelected) { 
            drawRingFittingInsideView(rect)
        }
    }
    
    internal func drawRingFittingInsideView(rect: CGRect) {
        let hw:CGFloat = ringThickness/2
        let circlePath = UIBezierPath(ovalInRect: CGRectInset(rect,hw,hw) )
        
        let shapeLayer = CAShapeLayer()
        shapeLayer.path = circlePath.CGPath
        shapeLayer.fillColor = UIColor.clearColor().CGColor
        shapeLayer.strokeColor = ringColor.CGColor
        shapeLayer.lineWidth = ringThickness
        layer.addSublayer(shapeLayer)
    }
}

import UIKit

@IBDesignable
class DrawCircles: UIView {

    override init(frame: CGRect) {
        super.init(frame: frame)
    }

    required public init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    override func draw(_ rect: CGRect) {

        guard let context = UIGraphicsGetCurrentContext() else {
            print("could not get graphics context")
            return
        }

        context.setLineWidth(2)

        context.setStrokeColor(UIColor.blue.cgColor)

        context.addEllipse(in: CGRect(x: 30, y: 30, width: 50.0, height: 50.0))

        context.strokePath()

        context.setStrokeColor(UIColor.red.cgColor)

        context.beginPath() // this prevents a straight line being drawn from the current point to the arc

        context.addArc(center: CGPoint(x:100, y: 100), radius: 20, startAngle: 0, endAngle: 2.0*CGFloat.pi, clockwise: false)

        context.strokePath()
    }
}

当它运行时，应该是这样的。我希望你喜欢我的解决方案
你有很多方法可以做到这一点，SpriteKit、Core Graphics等。你可能应该为我们再确定一点。根本看不出有什么原因，有人会投票来结束这个问题吗？@Joe我非常肯定，作为管理员，你可以为某些活动（包括结束问题）赢得分数。这可能解释了为什么有五个人在问题已经结束的时候（其中四个人）被引用为结束问题。嗨，文斯，对，我不明白。这个问题被关闭了，这真是太奇怪了。它也被标记为“不清楚”。再清楚不过了，非常清楚。奇怪的问题:
let myView = DrawCircles(frame: CGRect(x: 50, y: 50, width: 300, height: 300))

self.view.addSubview(myView)