Question

我正在创建一个应用程序，它使用tabbar.i创建了一个名为setuptabbar的函数，该函数调用所有使用tabbar的类。这是我的代码。

-(void)setupTabbar{
    //this is used to allocate space for tab bar item.
    TJourneylistController *journeylist =[[TJourneylistController alloc]initWithNibName:nil bundle:nil];
    UINavigationController *journeylistnavigation =[[UINavigationController alloc]initWithRootViewController:journeylist];
    [journeylist.tabBarItem initWithTitle:@"Journey List" image:[UIImage imageNamed:@""] tag:2];
    [journeylist release];

    TAppStoreController *appstore =[[TAppStoreController alloc]initWithNibName:nil bundle:nil];
    UINavigationController *appstorenavigation =[[UINavigationController alloc]initWithRootViewController:appstore];
    [appstore.tabBarItem initWithTitle:@"App Stroe" image:[UIImage imageNamed:@""] tag:1];
    [appstore release];

    TSettingsController *settings =[[TSettingsController  alloc]initWithNibName:nil bundle:nil];
    UINavigationController *settingsnavigation =[[UINavigationController alloc]initWithRootViewController:settings];
    [settings.tabBarItem initWithTitle:@"Journey List" image:[UIImage imageNamed:@""] tag:3];
    [settings release];

    TAboutController *about =[[TAboutController alloc]initWithNibName:nil bundle:nil];
    UINavigationController *aboutnavigation =[[UINavigationController alloc]initWithRootViewController:about];
    [about.tabBarItem initWithTitle:@"Journey List" image:[UIImage imageNamed:@""] tag:4];
    [about release];

    mTabController.viewControllers = [[NSArray alloc] initWithObjects:appstorenavigation,journeylistnavigation,settingsnavigation,aboutnavigation,nil];
    [appstorenavigation release];
    [journeylistnavigation release];
    [settingsnavigation release];
    [aboutnavigation release];
}


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    

    // Override point for customization after application launch.

    mTabController = [[UITabBarController alloc]init];
    [self setupTabbar];
    if([launchOptions objectForKey:UIApplicationLaunchOptionsRemoteNotificationKey]!=nil)
        mTabController.selectedViewController = [mTabController.viewControllers objectAtIndex:0];
    [mTabController presentModalViewController:mViewController animated:YES];
     //Screen *screen =[[Screen alloc]initWithNibName:@"Screen" bundle:nil];
    [window addSubview:mTabController.view];
    [self.window makeKeyAndVisible];
    //[screen release];

    return YES;
}

但是当我运行项目时，它给了我一个错误，'应用程序试图呈现一个零模态视图控制器。问题是什么。

Answer 1

在你的行中：

[mTabController presentModalViewController:mViewController animated:YES];

您正在从mTabController呈现mViewController。什么是mViewController？这可能是因为从未分配过mViewController。如果删除此行，我认为您的代码正在运行。

如何使用nil模态视图创建标签栏控制器

1 个答案: