iOS - 动画背景问题

Posted 2023-03-21

【中文标题】iOS - 动画背景问题

【英文标题】：iOS - Animating background issue

【发布时间】：2017-12-05 11:35:48

【问题描述】：

我正在尝试为屏幕上的几个元素设置动画，代码如下：

  private func setupAnimations() 

    self.emailAddress.alpha = 0
    self.fullName.alpha = 0
    self.password.alpha = 0
    self.confirmPassword.alpha = 0
    self.signUp.alpha = 0
    self.fullName.leftView?.alpha = 0
    self.emailAddress.leftView?.alpha = 0
    self.password.leftView?.alpha = 0
    self.confirmPassword.leftView?.alpha = 0

    self.emailAddress.center.x += self.view.bounds.width-10
    self.fullName.center.x -= self.view.bounds.width-10
    self.password.center.x -= self.view.bounds.width-10
    self.confirmPassword.center.x += self.view.bounds.width-10
    self.signUp.center.y += self.view.bounds.height/2

    UIView.animate(withDuration: 1.7, delay: 0.2, usingSpringWithDamping: 0.7, initialSpringVelocity: 0.5, options: [.allowUserInteraction,.curveEaseInOut], animations: 

        self.emailAddress.alpha = 1
        self.emailAddress.center.x -= self.view.bounds.width-10
        self.view.layoutIfNeeded()

    , completion: (completed) in

        if completed 

            UIView.animate(withDuration: 1, animations: 
                self.fullName.leftView?.alpha = 1
                self.emailAddress.leftView?.alpha = 1
                self.password.leftView?.alpha = 1
                self.confirmPassword.leftView?.alpha = 1
            )

        

    )

    UIView.animate(withDuration: 1.7, delay: 0, usingSpringWithDamping: 0.7, initialSpringVelocity: 0.5, options: [.allowUserInteraction,.curveEaseInOut], animations: 

        self.fullName.alpha = 1
        self.fullName.center.x += self.view.bounds.width-10
        self.view.layoutIfNeeded()

    , completion: (completed) in

        if completed 

            UIView.animate(withDuration: 1, animations: 
                self.fullName.leftView?.alpha = 1
                self.emailAddress.leftView?.alpha = 1
                self.password.leftView?.alpha = 1
                self.confirmPassword.leftView?.alpha = 1
            )

        

    )

等等......你明白了 - 我将 alpha 设置为 0 并将 x 居中设置为离屏，并为其“到达”屏幕设置动画，在 viewDidLoad() 中调用它。一切都解决了一个月，但最近我检查了这个问题：

视频链接：https://streamable.com/lhqvu

作为超级视图中的 UIImage 的背景也正在被动画化，从而可以看到超级视图（红色背景）。

任何帮助将不胜感激。提前谢谢你。

【问题讨论】：

在 viewDidAppear 方法中尝试所有动画，将您的代码分成两部分在视图中执行是否加载 1）初始设置，您设置所有 alpha 0 和您设置的任何帧 2）（在视图中执行确实出现了）应用动画

【参考方案1】：

在viewWillAppear 中添加您的动画setupAnimations 方法，并从usingSpringWithDamping 块中删除self.view.layoutIfNeeded()。在情节提要中取消选中 safeArea 并在将顶部约束设置为 superview 时取消选中 Constrain to margins 并设置为零。

【参考方案2】：

当涉及到动画时，您应该调用 viewDidAppear 上的函数，而不是 viewDidLoad。