如何在所有屏幕尺寸上调整视图大小？

Question

I am creating a simple timer app and want to resize the timer circle to the size of the view with the rounded corners. The timer path is added within the background views class.

On my iPhone XS Max, it looks like this:

But, on the iPhone SE simulator, it looks like this:

How can I ensure the timer circles resize correctly?

This is my code for the sizing of the circle paths:

private func addTimerCircle() {
    let translateAmount = -(CGFloat.pi/2)

    let circlePath = UIBezierPath(arcCenter: CGPoint.zero, radius: (self.frame.width - 64)/2, startAngle: translateAmount, endAngle: (2*CGFloat.pi)+translateAmount, clockwise: true)

    addTrackLayer(withPath: circlePath)
}

private func addTrackLayer(withPath circlePath: UIBezierPath) {
    let trackLayer = CAShapeLayer()

    trackLayer.path = circlePath.cgPath

    trackLayer.strokeColor = UIColor.red.withAlphaComponent(0.5).cgColor
    trackLayer.lineWidth = 10
    trackLayer.position = CGPoint(x: frame.size.width / 2, y: frame.size.height / 2)
    trackLayer.fillColor = UIColor.clear.cgColor
    layer.addSublayer(trackLayer)
}

Why does the circlePath not resize based on frame.width on the different screen sizes?

Thanks for any help!

Answer 1

View controller views are loaded with the size they have in Interface Builder, and once they are added to the hierarchy the view is resized to the actual size.

I'm guessing you're calling addTimerCircle() on viewDidLoad() , which happens before the final sizing is applied.

You could override viewDidLayoutSubviews() , which will be called when the view size changes, and add/update the shape there, but my suggestion would be to subclass UIView , add the shape layer as a property, and update it's frame on layoutSubviews .