如何獲取 Swift 中子層的填充顏色？

Question

我在各個 UIView 中創建了許多圓圈。 圓圈由 CAShapeLayer 制成，具有不同的 colors。

每個 UIView 都保存在一個數組中。

當我在數組中選擇一個隨機索引時，我想用該索引“測量”圓的顏色。

我試圖訪問 UIView 的子層，然后獲取它的“背景顏色”。 但我得到一個零值。

func createBalls(addToView circleView: UIView, x: CGFloat, y: CGFloat, size: CGFloat, color: CGColor) -> UIView {
    //create view to contain circle
    let containerView: UIView = {
            let view = UIView()
            view.backgroundColor = .clear
            return view
    }()
    // add container view to view
    containerView.frame = CGRect(x: x + size/2, y: y + size/2, width: size, height: size)
    circleView.addSubview(containerView)
    //create circle inside container view
    let path = UIBezierPath(ovalIn: containerView.bounds)
    let shapeLayer = CAShapeLayer()
    shapeLayer.path = path.cgPath
    shapeLayer.fillColor = color
    shapeLayer.lineWidth = 3
    shapeLayer.strokeColor = UIColor.black.cgColor
    containerView.layer.addSublayer(shapeLayer)
    circleView.clipsToBounds = false
    return containerView
}

func sampleOfCircles(addToView circleView: UIView, circleSize: CGFloat) {
    nBalls = Int.random(in: 3...5)
    nRedBalls = Int.random(in: 1...nBalls - 1)
    nBlueBalls = nBalls - nRedBalls
    for i in 0...nBalls-1 {
        let x = CGFloat(10 + i*(Int(circleSize) + 5))
        let y = circleView.frame.height/2
        if i < nRedBalls {
            ballArray.append(createBalls(addToView: circleView, x: x, y: y, size: circleSize, color: UIColor.red.cgColor))
        } else {
            ballArray.append(createBalls(addToView: circleView, x: x, y: y, size: circleSize, color: UIColor.blue.cgColor))
        }
    }
}

func createBallProblem(viewStackLeft: UIView, viewStackRight: UIView, viewBottom: UIView) {
   sampleOfCircles(addToView: viewStackLeft, circleSize: K.Ball.ballWidth)
   for a in ballArray {
      let color = a.layer.sublayers?.last?.backgroundColor
      print(color)
   }     
}
            

Answer 1

您正在使用fillColor將顏色設置為圖層，而不是backgroundColor 。 這就是你收到nil的原因。

要檢索您設置的顏色，請使用以下代碼：

let color = (a.layer.sublayers?.last as? CAShapeLayer)?.fillColor
print(color)