ios - 标签栏未出现在 applicationDidBecomeActive 上

Question

要求 - 当用户从后台 tabBar 打开应用程序时，所选索引应为 2

我尝试过的 -

//For getting current visible controller -
    public extension UIWindow {
        public var visibleViewController: UIViewController? {
            return UIWindow.getVisibleViewControllerFrom(self.rootViewController)
        }

        public static func getVisibleViewControllerFrom(_ vc: UIViewController?) -> UIViewController? {
            if let nc = vc as? UINavigationController {
                return UIWindow.getVisibleViewControllerFrom(nc.visibleViewController)
            } else if let tc = vc as? UITabBarController {
                return UIWindow.getVisibleViewControllerFrom(tc.selectedViewController)
            } else {
                if let pvc = vc?.presentedViewController {
                    return UIWindow.getVisibleViewControllerFrom(pvc)
                } else {
                    return vc
                }
            }
        }
    }
let appdelegate = UIApplication.shared.delegate as! AppDelegate

    //Selected 2 tabbar -
         func applicationDidBecomeActive(_ application: UIApplication) {
                if appdelegate.window?.visibleViewController != nil {
                    appdelegate.window?.visibleViewController?.hidesBottomBarWhenPushed = false
                    appdelegate.window?.visibleViewController?.navigationController?.popToRootViewController(animated: true)

                    appdelegate.window?.visibleViewController?.tabBarController?.selectedIndex = 2
                    appdelegate.window?.visibleViewController?.tabBarController?.tabBar.isHidden = false
                    appdelegate.window?.bringSubview(toFront: (appdelegate.window?.visibleViewController?.tabBarController?.view)!)

                }
            }

代码工作正常，但问题是 Tabbbar 被隐藏。为什么？

Answer 1

如果每个选项卡都有一个 navigationController，这将起作用

if let tabController = self.window!.rootViewController as? UITabBarController {
         if let navController =  tabBarController.selectedViewController as? UINavigationController{
              navController.popToRootViewController(animated: true)
              tabBarController.selectedIndex = 2
     }
}