iphone - 単一ビュー アプリケーションにタブバーを適用する必要がある

Question

xcode4.2 を使用しています。シングル ビュー アプリケーションのタブバーに 3 つの項目を追加しました。

問題は、ios シミュレーターに黒い画面が表示されるのではなく、出力を視覚化できないことです。

誰でも私を助けてくれますか

私のコードは

@synthesize window = _window;
@synthesize viewController = _viewController;
@synthesize appNavigation = _appNavigation;  

- (void)dealloc
{
    [_window release];
    [_viewController release];
    [_appNavigation release];    
    [super dealloc];
}



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

    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
        self.viewController = [[[ViewController alloc] initWithNibName:@"ViewController" bundle:nil] autorelease];

            UITabBarController *tabController = [[UITabBarController alloc] init];
            NSMutableArray *tabsArray = [[NSMutableArray alloc] init];
            `enter code here`ViewController *homeScreen = [[ViewController alloc] init];
            homeScreen.navigationItem.title = @"App Title";
            _appNavigation = [[UINavigationController alloc]initWithRootViewController:homeScreen];
            _appNavigation.tabBarItem.title = @"Home";
            [_appNavigation.tabBarItem setImage:[UIImage imageNamed:@"Home_Button.png"]];
            [tabsArray addObject:_appNavigation];
            [_appNavigation release];

            BookmarksViewController *bookMark = [[BookmarksViewController alloc] init];
            bookMark.navigationItem.title = @"Bookmarks";
            _appNavigation = [[UINavigationController alloc] initWithRootViewController:bookMark];
            [_appNavigation.tabBarItem initWithTabBarSystemItem:UITabBarSystemItemBookmarks tag:2];
            _appNavigation.tabBarItem.title = @"Bookmarks";
            [tabsArray addObject:_appNavigation];
            [_appNavigation release];

            AppSettingsController *settings = [[AppSettingsController alloc] initWithStyle:UITableViewStyleGrouped];
            settings.navigationItem.title = @"Settings";
            _appNavigation = [[UINavigationController alloc] initWithRootViewController:settings];
            _appNavigation.tabBarItem.title = @"Settings";
            [_appNavigation.tabBarItem setImage:[UIImage imageNamed:@"Settings_Button.png"]];
            [tabsArray addObject:_appNavigation];
            [_appNavigation release];

            SearchViewController *searchView = [[SearchViewController alloc] init];
            searchView.navigationItem.title = @"Ranga";
            _appNavigation = [[UINavigationController alloc] initWithRootViewController:searchView];
            _appNavigation.tabBarItem.title = @"Search";
            [_appNavigation.tabBarItem initWithTabBarSystemItem:UITabBarSystemItemSearch tag:4];
            [tabsArray addObject:_appNavigation];
            [_appNavigation release];


            tabController.viewControllers = tabsArray;


LoginViewController *loginView = [[LoginViewController alloc] init];

           [self.window addSubview:tabController.view];

[tabController presentModalViewController:loginView animated:NO];

    [self.window makeKeyAndVisible];
    return YES;
}


@end