如何在animationController（UIViewControllerTransitioningDelegate）中使用源（不呈现）？

Question

我正在制作一个自定义过渡管理器。它符合协议 UIViewControllerAnimatedTransitioning & UIViewControllerTransitioningDelegate。

当presenting从RocketsVC到RocketDetailsVC时，func被称为animationController（for Presentedpresented: UIViewController,presenting:UIViewController,source:UIViewController )，以下类型被传递到那里：

• presented: RocketDetailsViewController
• presenting: MainTabBarController （错误在这里）
• source： RocketsViewController

这个函数在 TransitionManager.swift 中声明：

func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
    type = .presentation
    return self // TransitionManager
}

然后 animateTransition 方法被调用...

func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
    guard let fromViewController = transitionContext.viewController(forKey: .from) as? TransitionManagerProtocol,
        let toViewController = transitionContext.viewController(forKey: .to) as? TransitionManagerProtocol

...效果为零，因为 MainTabBarController 不符合 TransitionManagerProtocol。

如果我构建一个没有 MainTabBarController 的项目（rootVC 是 RocketsVC），那么一切都会按预期进行。

我应该怎么做才能使转换工作？我在 MainTabBarController 上犯了罪，但也许有一种方法可以以某种方式传递给 animationController 方法source 而不是 presenting？

完整代码位于我的 GitHub

TransitionManager.swift
RocketsViewController.swift
MainTabBarController.swift

Answer 1

我花了很长时间找到的解决方案：

private var fromVC: UIViewController?
private var toVC: UIViewController?

...

func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
    type = .presentation
    fromVC = source
    toVC = presented
    return self
}

func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
    type = .dismissal
    toVC = fromVC // last `fromVC` is now `toVC`
    fromVC = dismissed // and now we set this to fromVC
    return self
}

并且：

func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
    guard let fromViewController = fromVC as? TransitionManagerProtocol,
          let toViewController = toVC as? TransitionManagerProtocol
    else {
        transitionContext.completeTransition(false)
        return
    }
    ...