添加UITabBarController并且没有NavigationController

问题描述

由于我是Xamarin.IOS的新手，所以我想问一个问题.我遵循了此示例在Xamarin.IOS项目中添加UITabBarController.

As I'm new in Xamarin.IOS, I'd like to ask a question.I've followed this example for adding UITabBarController in a Xamarin.IOS project.

当我通过TabController的实例初始化RootViewController时，它可以正常工作，并且我具有所有选项卡.但是我的NavigationController设置为null！这意味着:

When I initialized RootViewController by an instance of TabController, it works fine and I have all tabs.BUT my NavigationController set null ! it means that :

1. NavigationItem将消失

2. 无法通过此代码在viewController之间导航:

1. NavigationItem will disappear

2. navigating between viewControllers are not possible by this code :

this.NavigationController.PushViewController(new ProfileViewController(), true);

因为NavigationController为null！这是我在AppDelegate中的代码:

because the NavigationController is null !Here is my code in AppDelegate:

_tabController = new TabController();
_window.RootViewController = _tabController;

和我的TabController:

and my TabController :

public class TabController : UITabBarController
    {

        UIViewController tab1, tab2, tab3, tab4;

        public TabController()
        {
            tab1 = new HomeViewController();
            tab1.TabBarItem.Image = UIImage.FromFile("Icons/Home.png");

            tab2 = new TagCategoryViewController(null, null, 1, null);
            tab2.TabBarItem.Image = UIImage.FromFile("Icons/Tag.png");

            tab3 = new SearchViewController();
            tab3.TabBarItem.Image = UIImage.FromFile("Icons/Search.png");

            tab4 = new ProfileViewController();
            tab4.TabBarItem.Image = UIImage.FromFile("Icons/Home.png");

            var tabs = new UIViewController[] {
                tab1, tab2, tab3,tab4
            };

            ViewControllers = tabs;
        }
    }

此外，我有很多UIViewControllers，我都是通过编程方式完成的，因此我不使用StoryBoard！

In additional, I have lots of UIViewControllers and I do all of them programmatically and I dont use StoryBoard !

推荐答案

通过将TabController包装在UINavigationController中.

_tabController = new TabController();
_window.RootViewController = new UINavigationController(_tabController);

这样，NavigationController属性将不会为null，并且可以完成导航.

This way NavigationController property won't be null and navigation can be done.

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