Question

我正在尝试显示NavigationController并在完成块中选择第二个选项卡。我的代码是：

public class Client {
    private UserClass User { get; };

    public Client(UserClass user)
    {
        User = user;
    }

    public void Verify(string serveraddress, string domain)
    {
        try 
        {
            var connection = new LdapConnection();
            connection.Connect(serveraddress, 389);
            // try to connect, if success go through this step and return true
            return true;
        }
        catch
        {
            return false;
        }
    }

    public string GetEmail()
    {
        // Connect again
        // Here, it is redundant when I have to connect again to retrieve the information
    }
}

第二次尝试：

let chatViewController = UITabBarController()
let navigationController = UINavigationController(rootViewController: chatViewController)

present(navigationController, animated: true, completion: {
    self.visibleViewController = navigationController
    self.visibleViewController?.tabBarController?.selectedIndex = 1
})

在两种情况下，tabBarController均为nil。如何切换到其他标签？

Answer 1

您正尝试访问UITabBarController中的UINavigationController，但是您需要从UINavigationController访问第一个控制器，并且需要从此处选择UITabBar这样：

func showTabBarControllerr() {
    let chatViewController = UITabBarController()
    //Note: Make sure you have already added the Controllers in Tabbarcontroller
    chatViewController.viewControllers = [DemoOne(), DemoTwo()]
    let navigationController = UINavigationController(rootViewController: chatViewController)
    present(navigationController, animated: true, completion: {
        if let tabBarController = navigationController.viewControllers.first as? UITabBarController {
            tabBarController.selectedIndex = 1
        }
    })
}

让我知道这是否有帮助！

Answer 2

代替呼叫

present(navigationController, animated: true, completion: { })

在viewDidLoad中，尝试在viewWillAppear或viewDidAppear

中调用它

Answer 3

尝试一下（快速5）：

在情节提要中为UITabBarController设置一个标识符，类似于MainTabBar
在函数或IBAction中，使用以下代码：

让tbc = storyboard？.instantiateViewController（withIdentifier：“ MainTabBar”）为！ UITabBarController

tbc.selectedIndex = 1 //这是您的控制器的索引

present（待定，动画：false，完成：nil）

使用TabBarViewController呈现NavigationController无法以编程方式选择索引

3 个答案: