iOS 26中hidesBottomBarWhenPushed交互返回TabBar层级异常问题

1. 这是iOS 26的预期行为吗？ #

从目前开发者社区反馈和苹果官方文档来看，这更像是版本回归bug而非预期行为。iOS 16及后续版本曾出现过类似的TabBar层级渲染问题，iOS 26的该表现大概率属于同一类问题，并非苹果有意调整的交互逻辑。

2. 是否仍应使用hidesBottomBarWhenPushed，还是有新的API/模式？ #

hidesBottomBarWhenPushed仍是官方推荐的隐藏TabBar的标准API，目前没有替代它的官方新接口或模式。只要你的业务场景需要在push页面时隐藏TabBar，这个属性依然是首选方案。

3. 如何恢复iOS 26之前的行为，让交互过渡时TabBar保持在详情视图后方？ #

提供三种可行方案，可根据项目场景选择：

方案一：自定义导航控制器转场代理 #

通过实现UINavigationControllerDelegate手动控制转场过程中的TabBar层级：

class CustomNavigationController: UINavigationController, UINavigationControllerDelegate {
    override func viewDidLoad() {
        super.viewDidLoad()
        delegate = self
    }

    func navigationController(_ navigationController: UINavigationController, animationControllerFor operation: UINavigationController.Operation, from fromVC: UIViewController, to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        if operation == .pop {
            return CustomPopTransition()
        }
        return nil
    }
}

class CustomPopTransition: NSObject, UIViewControllerAnimatedTransitioning {
    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
        return 0.35
    }

    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
        guard let fromVC = transitionContext.viewController(forKey: .from),
              let toVC = transitionContext.viewController(forKey: .to) else {
            transitionContext.completeTransition(false)
            return
        }
        
        let containerView = transitionContext.containerView
        containerView.addSubview(toVC.view)
        containerView.sendSubviewToBack(toVC.view)
        
        fromVC.view.frame = containerView.bounds
        let finalFrame = CGRect(x: containerView.bounds.width, y: 0, width: containerView.bounds.width, height: containerView.bounds.height)
        
        UIView.animate(withDuration: transitionDuration(using: transitionContext)) {
            fromVC.view.frame = finalFrame
            if let tabBar = (toVC as? UITabBarController)?.tabBar {
                containerView.sendSubviewToBack(tabBar)
            }
        } _ in
            fromVC.view.removeFromSuperview()
            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
        }
    }
}

方案二：监听侧滑手势动态调整TabBar层级 #

在详情页监听导航控制器的侧滑手势，根据手势状态调整TabBar层级：

class DetailViewController: UIViewController {
    private var tabBar: UITabBar?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        tabBar = tabBarController?.tabBar
        
        if let popGesture = navigationController?.interactivePopGestureRecognizer {
            popGesture.addTarget(self, action: #selector(handlePopGesture(_:)))
        }
    }
    
    @objc private func handlePopGesture(_ gesture: UIPanGestureRecognizer) {
        guard let tabBar = tabBar else { return }
        
        switch gesture.state {
        case .began, .changed:
            tabBar.superview?.sendSubviewToBack(tabBar)
        case .cancelled:
            tabBar.superview?.bringSubviewToFront(tabBar)
        default:
            break
        }
    }
}

方案三：修改TabBar的zPosition（简洁版） #

在详情页生命周期方法中直接调整TabBar的层级：

class DetailViewController: UIViewController {
    private var originalZPosition: CGFloat = 0
    
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        if let tabBar = tabBarController?.tabBar {
            originalZPosition = tabBar.layer.zPosition
            tabBar.layer.zPosition = -1000
        }
    }
    
    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        if let tabBar = tabBarController?.tabBar {
            tabBar.layer.zPosition = originalZPosition
        }
    }
}

注意：该方案实现简单，但直接修改layer的zPosition可能影响其他视图层级，需充分测试后使用。

内容的提问来源于stack exchange，提问作者ChaseChoi