如何围绕环中的中心点绘制圆形按钮? [英] How to plot circular buttons around a central point in a ring?

问题描述

我正在尝试在这样的环中绘制圆形按钮.

I am attempting to plot circular buttons in a ring like this.

我有 6 个 UI 按钮，它们的圆角半径均为 360 度，我试图在 Swift 中做的是将它们均匀地绘制在中央按钮/点周围，就像上图一样.每个圆与其邻居等距.实现此功能的最佳方法是什么?我应该创建一条贝塞尔曲线，然后使用数学方法在所述曲线周围绘制按钮，还是您有其他建议?

I have 6 UI buttons which all have a corner-radius of 360 degrees, what I am attempting to do in Swift is plot them equally around a central button/point just like the image above. Each circle is equally spaced from its neighbour. What is the best way of achieving this functionality? Should I create a bezier curve and then use math to plot the buttons around said curve or is there another way which you would suggest?

旁注是我不是在寻找任何类型的径向菜单，不需要动画.我只是想以上面的格式绘制我现有的 UI 按钮.

A side note is that I am not looking for a radial menu of any kind there is no animation required. I am just trying to plot my existing UI Buttons in the format above.

谢谢！

推荐答案

我建议使用 math (trigonometry) 来计算中心按钮的水平和垂直偏移，然后使用布局锚来定位按钮.

I would suggest using math (trigonometry) to compute the horizontal and vertical offsets from the center button and then use layout anchors to position the buttons.

这是一个自包含的例子:

Here is a self contained example:

class ViewController: UIViewController {

    func createButton(size: CGFloat) -> UIButton {
        let button = UIButton(type: .custom)
        button.backgroundColor = .red
        button.translatesAutoresizingMaskIntoConstraints = false
        button.widthAnchor.constraint(equalToConstant: size).isActive = true
        button.heightAnchor.constraint(equalToConstant: size).isActive = true
        button.layer.cornerRadius = size / 2

        return button
    }

    func setUpButtons(count: Int, around center: UIView, radius: CGFloat) {
        // compute angular separation of each button
        let degrees = 360 / CGFloat(count)

        for i in 0 ..< count {
            let button = createButton(size: 50)
            self.view.addSubview(button)

            // use trig to compute offsets from center button
            let hOffset = radius * cos(CGFloat(i) * degrees * .pi / 180)
            let vOffset = radius * sin(CGFloat(i) * degrees * .pi / 180)

            // set new button's center relative to the center button's
            // center using centerX and centerY anchors and offsets
            button.centerXAnchor.constraint(equalTo: center.centerXAnchor, constant: hOffset).isActive = true
            button.centerYAnchor.constraint(equalTo: center.centerYAnchor, constant: vOffset).isActive = true
        }
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        let centerButton = createButton(size: 50)
        self.view.addSubview(centerButton)

        // use anchors to place center button in the center of the screen
        centerButton.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive = true
        centerButton.centerYAnchor.constraint(equalTo: self.view.centerYAnchor).isActive = true

        setUpButtons(count: 6, around: centerButton, radius: 100)
    }

}

注意事项:

• 如果不需要中心按钮，只需在self.view周围设置按钮:

setupButtons(count: 6, around: self.view, radius: 100)

或在任意点附近:

let point = CGPoint(x: 180, y: 300)
let centerView = UIView(frame: CGRect(origin: point, size: CGSize.zero))
self.view.addSubview(centerView)
setUpButtons(count: 6, around: centerView, radius: 140)

使用 UIView 作为中心而不是点更灵活，因为您可以动态移动 UIView 并且按钮将跟随.

Using a UIView as the center instead of a point is more flexible because you can dynamically move that UIView and the buttons will follow.

这里是在模拟器中运行:

Here it is running in the simulator:

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