Question

我有一个UITabBarController，它有9个视图控制器，我使用前进和后退按钮自定义处理导航。我创建了一个UIViewControllerAnimatedTransitioning对象来处理动画（从左到右简单），并在委托方法中返回它：

tabBarController(_ tabBarController: UITabBarController, animationControllerForTransitionFrom fromVC: UIViewController, to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning?

但是，在选择第五个索引时和之后，不再调用此函数（因为它现在由UIMoreNavigationController处理。是否有动画委托或某种方式我应该为{{{{1}处理它1}}实例？

Answer 1

您需要指定moreNavigationController的委托。因此，在您的UITabBarController类中，您需要：

        self.moreNavigationController.delegate = strongDelegate // where strongDelegate is a local instance of MyControllerDelegate as defined below

然后，委托应实现NavigationController函数，该函数将调用适用的UIViewControllerAnimatedTransitioning实例：

class MyControllerDelegate: NSObject, UINavigationControllerDelegate {

func navigationController(_ navigationController: UINavigationController, animationControllerFor operation: UINavigationController.Operation, from fromVC: UIViewController, to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
    switch operation {
    case .push:
        return MyPresentationAnimationController(isPresenting: true)
    case .pop:
        return MyPresentationAnimationController(isPresenting: false)
    default:
        return nil
    }
}

}

您的animateTransition函数包含发生魔术的逻辑：

class MyPresentationAnimationController : NSObject, UIViewControllerAnimatedTransitioning {

private let isPresenting: Bool

init(isPresenting: Bool) {
    self.isPresenting = isPresenting
}

func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
    return TimeInterval(UINavigationController.hideShowBarDuration)
}

func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
    guard
        let toView = transitionContext.view(forKey: .to),
        let fromView = transitionContext.view(forKey: .from)
        else {
            return
    }
    let containerView = transitionContext.containerView

    // TODO: Implement the logic with UIView.animateKeyframes here ...

}

}

如何使用5个以上的ViewControllers为UITabBarController中的转换设置动画？

1 个答案: