UIView动画在iOS 8中无法正常运行？

Question

我想创建如下的动画，我在iOS 11.2中完成了这个。

我在iOS 8.4和9.2中测试了这一点 - broke

故事板

我使用了autoLaout

RoundedShadowButton

我将UIButton子类化。添加了RoundedCorner和DropShadow协议。它包含一个关注动画的animateButton函数。

class RoundedShadowButton: UIButton, RoundedCorner, DropShadow {
    var originalSize: CGRect?

    func animateButton(shouldLoad: Bool, withMessage message: String?) {
        let spinner = UIActivityIndicatorView()
        spinner.activityIndicatorViewStyle = .whiteLarge
        spinner.color = .darkGray
        spinner.alpha = 0.0
        spinner.hidesWhenStopped = true
        spinner.tag = 21

        if shouldLoad {
            self.addSubview(spinner)
            self.setTitle("", for: .normal)
            UIView.animate(withDuration: 0.2, animations: {
                self.setRoundedCorners(radius: self.frame.height / 2)
                self.frame = CGRect(x: self.frame.midX - (self.frame.height / 2), y: self.frame.origin.y, width: self.frame.height, height: self.frame.height)
            }, completion: { (finished) in
                if finished {
                    spinner.startAnimating()
                    spinner.center = CGPoint(x: self.frame.width / 2 + 1, y: self.frame.width / 2 + 1)
                    spinner.fadeTo(alphaValue: 1.0, withDuration: 0.2)
                }
            })
            self.isUserInteractionEnabled = false
        } else {
            self.isUserInteractionEnabled = true

            // remove spinner
            for subView in self.subviews {
                if subView.tag == 21 {
                    subView.removeFromSuperview()
                }
            }

            // return back to original button
            UIView.animate(withDuration: 0.2, animations: {
                if let size = self.originalSize {
                    self.setRoundedCorners(radius: 8)
                    self.frame = size
                    self.setTitle(message, for: .normal)
                }
            })
        }
    }
}

RoundedCorner

protocol RoundedCorner {}

extension RoundedCorner where Self: UIView {
    func setRoundedCorners(radius: CGFloat) {
        layer.cornerRadius = radius
    }
}

阴影效果

protocol DropShadow {}

extension DropShadow where Self: UIView {
    func setShadow(width: CGFloat = 0, height: CGFloat = 0, opacity: Float, radius: CGFloat, color: UIColor) {
        layer.shadowColor = color.cgColor
        layer.shadowOpacity = opacity
        layer.shadowOffset = CGSize(width: width, height: height)
        layer.shadowRadius = radius
    }
}

HomeVC

在HomeVC的viewDidAppear中，我设置了角半径，阴影和帧大小。在IBAction按钮中，我调用了animate函数。

override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        actionBtn.originalSize = actionBtn.frame
        actionBtn.setRoundedCorners(radius: 8)
        actionBtn.setShadow(opacity: 0.3, radius: 10.0, color: .darkGray)
    }

@IBAction func actionBtnTapped(_ sender: Any) {
        self.actionBtn.animateButton(shouldLoad: true, withMessage: nil)
    }

如何解决这个问题？

Answer 1

使用约束制作动画时，您还需要使用约束。虽然它有时可能有效，但它不是你可以依赖的东西。你可以这样解决它。

• 删除leading和trailing约束。
• 添加same width宽度限制为superview减去40。将其连接到名为NSLayoutConstraint的{​​{1}}类型的类变量。设置优先级widthConstraint。
• 添加另一个宽度约束，其750设置为与高度相同，因此它变为圆形。将优先级设置为width。
• 在500。{/ li>中向center添加约束

现在，在您的代码中替换帧修改部分。

superview

有了这个。通过更改优先级，您可以选择应该生效的约束。由于宽约束是750，它将胜过狭窄约束。将优先级更改为250时，窄约束将获胜。

            self.frame = CGRect(x: self.frame.midX - (self.frame.height / 2), y: self.frame.origin.y, width: self.frame.height, height: self.frame.height)

Answer 2

试试这个，我的工作只是禁用它：

   self.view.translatesAutoresizingMaskIntoConstraints  = false