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我下面的快速代码试图围绕另一个图像视图旋转一个图像视图。我希望旋转像游戏旋转器一样工作。与我正在寻找的内容接近的链接是https://www.orientaltrading.com/large-spinner-wheel-stand-up-a2-13846120.fltr。现在我的代码没有这样做，您可以在下面的 gif 中看到代码当前正在执行的操作。gif 没有按照我的意愿去做。我希望粉红色框的底部锚点是它的中心底部锚点，它连接到 uiviewcontroller 的中心。它以一种方式旋转 180 度。就像上面链接中的游戏微调器一样。

在此处输入图像描述

import UIKit

class ViewController: UIViewController {
    var box = UIImageView()
    var box1 = UIImageView()
    override func viewDidLoad() {
        super.viewDidLoad()

        box.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(box)
        box.backgroundColor = .systemPink
        box1.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(box1)
        box1.backgroundColor = .purple

        self.box.setAnchorPoint(anchorPoint: CGPoint(x: 0.5, y: 0.5))

        Rotate()

        NSLayoutConstraint.activate([
            box.heightAnchor.constraint(equalTo: view.heightAnchor, multiplier: 0.25),
            box.widthAnchor.constraint(equalTo: view.widthAnchor, multiplier: 0.25),
            box.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            box.bottomAnchor.constraint(equalTo: view.centerYAnchor),

            box1.heightAnchor.constraint(equalTo: view.heightAnchor, multiplier: 0.05),
            box1.widthAnchor.constraint(equalTo: view.heightAnchor, multiplier: 0.05),
            box1.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            box1.centerYAnchor.constraint(equalTo: view.centerYAnchor)
        ])
        // Do any additional setup after loading the view.
    }


    func Rotate(){

        let   rotation = UIViewPropertyAnimator(duration: 25, curve: .linear, animations: {

            self.box.transform = self.box.transform.rotated(by: CGFloat.pi/0.94)

        })
        rotation.startAnimation()

    }





}

extension UIView{
    func setAnchorPoint(anchorPoint: CGPoint) {

        var newPoint = CGPoint(x: self.bounds.size.width * anchorPoint.x, y: self.bounds.size.height * anchorPoint.y)
        var oldPoint = CGPoint(x: self.bounds.size.width * self.layer.anchorPoint.x, y: self.bounds.size.height * self.layer.anchorPoint.y)

        newPoint = newPoint.applying(self.transform)
        oldPoint = oldPoint.applying(self.transform)

        var position : CGPoint = self.layer.position

        position.x -= oldPoint.x
        position.x += newPoint.x;

        position.y -= oldPoint.y;
        position.y += newPoint.y;

        self.layer.position = position;
        self.layer.anchorPoint = anchorPoint;
    }
}
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2 回答 2

1

您的代码有两个问题：

  1. 锚点应等于 (0.5, 1)。（底部中心）。
  2. 您在不适当的时间设置锚点。您转换位置的代码是正确的，但是bounds是 (0, 0, 0, 0)。

从视图中删除setAnchorPoint和Rotate调用确实加载和添加方法，如下所示：

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    view.setNeedsLayout()
    view.layoutIfNeeded()

    self.box.setAnchorPoint(anchorPoint: CGPoint(x: 0.5, y: 1))
    Rotate()
}

viewWillAppear控制器视图的大小已经设置。并调用view.setNeedsLayout()和view.layoutIfNeeded()布局你的盒子。您可以在这些调用之前和之后检查box帧。

于 2020-06-10T05:55:12.417 回答
0

经过测试，它在本地工作。

    // No need for a seperate extension
    self.box.layer.anchorPoint = CGPoint(x: 0.5, y: 1)

    // Start Animation
    Rotate()

    NSLayoutConstraint.activate([
        box.heightAnchor.constraint(equalTo: view.heightAnchor, multiplier: 0.25),
        box.widthAnchor.constraint(equalTo: view.widthAnchor, multiplier: 0.25),
        box.centerXAnchor.constraint(equalTo: view.centerXAnchor),

        // Use centerYAnchor instead of bottomAnchor
        box.centerYAnchor.constraint(equalTo: view.centerYAnchor),

        box1.heightAnchor.constraint(equalTo: view.heightAnchor, multiplier: 0.05),
        box1.widthAnchor.constraint(equalTo: view.heightAnchor, multiplier: 0.05),
        box1.centerXAnchor.constraint(equalTo: view.centerXAnchor),
        box1.centerYAnchor.constraint(equalTo: view.centerYAnchor)
    ])
    // Do any additional setup after loading the view.
}

// Use simple UIView animation
func Rotate(){
    UIView.animate(withDuration: 25) {
        self.box.transform = CGAffineTransform(rotationAngle: CGFloat.pi/0.94)
    }
}
于 2020-06-10T06:05:18.910 回答