ios - 从左侧滑动 UIBarButtonItem

Question

当转到二级页面时，我试图在 0.33 秒的时间内从左侧滑入后退按钮。现在动画似乎并没有这样做，即使在将持续时间减慢到 2 秒以进行视觉澄清之后也是如此。想知道是否有人可以告诉我我在代码中做错了什么以及如何更正它？

出来说我可能只是误解了动画的某些方面是如何工作的。

func addBackButton() {
        let backButton = UIButton(type: .custom)
        backButton.setImage(#imageLiteral(resourceName: "backArrow"), for: .normal)
        backButton.setTitle("", for: .normal)
        backButton.setTitleColor(backButton.tintColor, for: .normal)
        backButton.addTarget(self, action: #selector(backAction), for: .touchUpInside)
        let backBarButtonItem = UIBarButtonItem(customView: backButton)
        backBarButtonItem.customView?.transform = CGAffineTransform(translationX: -backButton.frame.width, y: 0)
        navigationItem.leftBarButtonItems?.insert(backBarButtonItem, at: 0)
        UIView.animate(withDuration: 2, delay: 0.5, animations: {
            backBarButtonItem.customView?.transform = CGAffineTransform(translationX: 2 * backButton.frame.width, y: 0)
        })
    }

Answer 1

您只需将此自定义按钮放入 containerView 并将该 containerView 设置为 UIBarButtonItem 的 自定义 View 。您的设置将如下所示，

let containerFrame = CGRect(origin: .zero, size: CGSize(width: 44.0, height: 44.0))
let container = UIView(frame: containerFrame)

let buttonFrame = CGRect(origin: CGPoint(x: -100, y: 0), size: CGSize(width: 44, height: 44))  
let backButton = UIButton(frame: buttonFrame)
backButton.setImage(#imageLiteral(resourceName: "backArrow"), for: .normal)
backButton.setTitle("", for: .normal)
backButton.setTitleColor(backButton.tintColor, for: .normal)
backButton.addTarget(self, action: #selector(backAction), for: .touchUpInside)
container.addSubview(backButton)

let backBarButtonItem = UIBarButtonItem(customView: container)
UIView.animate(withDuration: 2, delay: 0.5, animations: {
    backButton.transform = CGAffineTransform(translationX: 2 * backButton.frame.width, y: 0)
})

您可以检查为什么需要将自定义 button 包装在另一个 UIView 中 here .