self.tabBarController为NULL [英] self.tabBarController is NULL

问题描述

我创建了如下所示的UITabBarController并推送了NavigationController，但是由于tabbarcontroller为NULL，所以现在我无法设置标签栏项的标题等.

I created a UITabBarController like the following and pushed a navigationController, but I now cannot set the title of tab bar items etc... as the tabbarcontroller is NULL.

请你告诉我我要去哪里错了.

Please can you tell me where I am going wrong.

UITabBarController *tabBarController = [[UITabBarController alloc] init];
        LoggedInFeedNavigationController *lvc = [[LoggedInFeedNavigationController alloc] initWithAccount:account];
        [tabBarController setViewControllers:[NSArray arrayWithObject:lvc]];
        [tabBarController setSelectedIndex:0];
        [self presentModalViewController:tabBarController animated:YES];
        [tabBarController release];
        [lvc release];

推荐答案

在

In the documentation for tabBarController I see the following

如果没有标签栏，则或 接收者是模式视图， 属性为零.

If no tab bar is present or the receiver is a modal view, this property is nil.

在注释中说您正在从LoggedInFeedNavigationController内部调用self.tabBarController，我认为它应该可以正常工作.但是，您正在以模式方式显示选项卡栏，并且如果文档的意思是即使它在UITabBarController内作为模式视图也存在，那么这就是您的问题.

In the comments it says that you are calling self.tabBarController from within the LoggedInFeedNavigationController and I would think it should work properly. But you are displaying the tab bar modally and if the documentation means even if it is inside of UITabBarController as a modal view then that is your problem.

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