ios - 应用程序尝试以模态方式呈现事件 Controller - 导航 Controller

Question

对于标签栏 Controller 的第二项，我有一个想要以模态方式呈现的导航 Controller 。我不断收到错误消息

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Application tried to present modally an active controller .'

然后我的应用程序崩溃并转到应用程序委托(delegate)。

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 中处于事件状态的 View Controller ，这就是应用程序崩溃的原因。 尝试使用这个

    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
}