问题描述
我正在向另一个视图添加自定义视图,然后以编程方式设置其约束。这导致视图的内容绘制在错误的位置,我不确定为什么。这是我拥有的代码以及到目前为止我尝试过的代码:
// Called in viewDidLoad
let buttonView = UIView()
buttonView.translatesAutoresizingMaskIntoConstraints = false
let ring = CircularProgressView()
ring.frame = CGRect(x: 0,y: 0,width: 80,height: 80)
ring.backgroundColor = .yellow
buttonView.addSubview(ring)
self.view.addSubview(buttonView)
NSLayoutConstraint.activate([
buttonView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor,constant: -12),buttonView.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor,constant: -28),buttonView.heightAnchor.constraint(equalToConstant: 80),buttonView.widthAnchor.constraint(equalToConstant: 80),ring.centerXAnchor.constraint(equalTo: buttonView.centerXAnchor),ring.centerYAnchor.constraint(equalTo: buttonView.centerYAnchor)
])
我尝试调用ring.layoutIfNeeded()或使用约束设置环形视图的宽度和高度,但是它没有任何改变。
ring.heightAnchor.constraint(equalToConstant: 80),ring.widthAnchor.constraint(equalToConstant: 80)
CircleProgressView类如下所示。我尝试在此处使用边界而不是框架,或者不将值减2,然后再没有变化。
class CircularProgressView: UIView {
// First create two layer properties
private var circleLayer = CAShapeLayer()
private var progressLayer = CAShapeLayer()
private var currentValue: Double = 0
override init(frame: CGRect) {
super.init(frame: frame)
createCircularPath()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
createCircularPath()
}
func createCircularPath() {
let circularPath = UIBezierPath(arcCenter: CGPoint(x: frame.size.width / 2.0,y: frame.size.height / 2.0),radius: 41,startAngle: -.pi / 2,endAngle: 3 * .pi / 2,clockwise: true)
circleLayer.path = circularPath.cgPath
circleLayer.fillColor = UIColor.clear.cgColor
circleLayer.lineCap = .round
circleLayer.linewidth = 3.0
circleLayer.strokeColor = UIColor.black.withAlphaComponent(0.2).cgColor
progressLayer.path = circularPath.cgPath
progressLayer.fillColor = UIColor.clear.cgColor
progressLayer.lineCap = .round
progressLayer.linewidth = 3.0
progressLayer.strokeEnd = 0
progressLayer.strokeColor = UIColor.black.cgColor
layer.addSublayer(circleLayer)
layer.addSublayer(progressLayer)
let circularProgressAnimation = CABasicAnimation(keyPath: "strokeEnd")
circularProgressAnimation.duration = 2
circularProgressAnimation.tovalue = 1
circularProgressAnimation.fillMode = .forwards
circularProgressAnimation.isRemovedOnCompletion = false
progressLayer.add(circularProgressAnimation,forKey: "progressAnim")
progressLayer.pauseAnimation()
}
}
如果通过情节提要板进行操作,这一切都没有问题,但是我需要针对该用例以编程方式创建它,而我对问题所在感到困惑。
解决方法
您需要像编程一样制作两个视图
// Called in viewDidLoad
let buttonView = UIView()
buttonView.translatesAutoresizingMaskIntoConstraints = false
let ring = CircularProgressView()
ring.translatesAutoresizingMaskIntoConstraints = false
ring.backgroundColor = .yellow
buttonView.addSubview(ring)
self.view.addSubview(buttonView)
NSLayoutConstraint.activate([
buttonView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor,constant: -12),buttonView.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor,constant: -28),buttonView.heightAnchor.constraint(equalToConstant: 80),buttonView.widthAnchor.constraint(equalToConstant: 80),ring.centerXAnchor.constraint(equalTo: buttonView.centerXAnchor),ring.centerYAnchor.constraint(equalTo: buttonView.centerYAnchor),ring.heightAnchor.constraint(equalToConstant: 80),ring.widthAnchor.constraint(equalToConstant: 80)
])
仅在createCircularPath
内呼叫layoutSubviews
override func layoutSubviews() {
super.layoutSubviews()
createCircularPath()
}
,
还尝试将CircularProgressView
的{{1}}属性设置为translatesAutoresizingMaskIntoConstraints
:
false