Question

对于我的标签栏控制器的第二项，我有一个导航控制器，我想以模态方式呈现。我不断收到错误消息

由于未捕获的异常'NSInvalidArgumentException'而终止应用程序，原因：'应用程序尝试以模态方式呈现活动控制器。'

然后我的应用程序崩溃并转到应用代表。

这是我到目前为止的代码

func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
    if let restoreID = viewController.restorationIdentifier {
        if restoreID == "NavigationCamera" {
            if let nav = tabBarController.viewControllers![tabBarController.selectedIndex] as? UINavigationController {
                print("Nav is allowed")
                //let newVC = tabBarController.storyboard?.instantiateViewController(withIdentifier: "CameraView")

                tabBarController.present(nav, animated: true, completion: {
                    print("complete")
                })
                return false
            }
        }
    }
    return true
}

Answer 1

您正在尝试呈现已在UITabBarController中处于活动状态的viewcontroller，这就是应用程序崩溃的原因。尝试使用此

    func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
    if let restoreID = viewController.restorationIdentifier {
        if restoreID == "NavigationCamera" {
                print("Nav is allowed")
                let newVC = tabBarController.storyboard?.instantiateViewController(withIdentifier: "CameraView") as! UIViewController
                tabBarController.present(UINavigationController.init(rootViewController: newVC), animated: true, completion: {
                    print("complete")
                })
                return false
        }
    }
    return true
}

Answer 2

您需要尝试在tabBarController内更改selectedViewController属性，而不要使用本方法。试试这个

func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
    if let restoreID = viewController.restorationIdentifier {
        if let restoreID == "NavigationCamera" {
            print("Nav is allowed")
            tabBarController.selectedViewController = tabBarController.viewControllers![tabBarController.selectedIndex] as? UINavigationController
            return false
        }
    }
    return true
}

应用程序尝试以模态方式呈现活动控制器 - 导航控制器

2 个答案: