无法更改视图中绘制的圆的颜色

Question

我试图通过在类中创建一个方法来更新我在UIView的子类中创建的圆的颜色，以更新颜色，但颜色不会改变。

import UIKit

class badge: UIView {

    struct mine {
        static var p = UIBezierPath(ovalInRect: CGRectMake(0,0,100,100))

}

override func drawRect(rect: CGRect) {
    // Drawing code


    UIColor.blueColor().setFill()
    mine.p.fill()        

}


func colour(whatColour: String) {

    UIColor.redColor().setFill()
    mine.p.fill()
    self.setNeedsDisplay()

}
}

// The above is referenced in view controller with

@IBOutlet weak var myBadge: badge!

// change function colour is called with 

myBadge.colour()

// but the colour of the circle does not change (its still filled in blue)
}

我做错了什么？

Answer 1

更新：Swift 3（和Swift 4）语法：

setNeedsDisplay会导致draw再次运行，并将填充颜色设置为蓝色。尝试在Badge视图中添加属性以存储desiredColour：

class Badge: UIView {

    var desiredColour: UIColor = .blue

    struct mine {
        static var p = UIBezierPath(ovalIn: CGRect(x: 0, y: 0, width: 100, height: 100))
    }

    override func draw(_ rect: CGRect) {
        // Drawing code

        desiredColour.setFill()
        mine.p.fill()
    }

    func colour() {
        desiredColour = .red
        self.setNeedsDisplay()
    }
}

---

如果您将didSet添加到desiredColour，则可以让它为您调用setNeedsDisplay，然后您甚至不需要colour功能。因此，要使用它，只需调用myBadge.desiredColour = .red，视图就会重新绘制！

class Badge: UIView {

    var desiredColour: UIColor = .blue {
        didSet {
            self.setNeedsDisplay()
        }
    }

    struct mine {
        static var p = UIBezierPath(ovalIn: CGRect(x: 0, y: 0, width: 100, height: 100))
    }

    override func draw(_ rect: CGRect) {
        // Drawing code

        desiredColour.setFill()
        mine.p.fill()
    }
}

---

这是在Swift游乐场中运行的：