从 ModalViewController 中选择第二个选项卡

Question

在我的应用程序委托中，我在选项卡栏顶部加载了一个视图控制器。该控制器上有三个按钮，一个用于导航到每个选项卡。当按下第二个按钮时，我想关闭视图控制器并转到第二个选项卡。但这似乎并不按正常方式工作。

我的 AppDelegate：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 
{    
    //-- Insert a delay of 5 seconds before the splash screen disappears
    [NSThread sleepForTimeInterval:3.0];        

    // Set the tab bar controller as the window's root view controller and display.
    self.window.rootViewController = self.tabBarController;

    // Set StartView to load first
    StartViewController *startViewController = [[StartViewController alloc] initWithNibName:@"StartView" bundle: nil];
    [window addSubview: [startViewController view]];
    [window makeKeyAndVisible];

    [self.tabBarController presentModalViewController:startViewController animated:NO];
    [startViewController release];

    return YES;
}

这是我当前的 IBAction，它似乎不起作用：

 - (IBAction) toSecondView:(id)sender
    {
    // Show status bar
    [[UIApplication sharedApplication] setStatusBarHidden:NO withAnimation:UIStatusBarAnimationNone];

    [(UITabBarController *)self.parentViewController setSelectedIndex:1];

    [self dismissModalViewControllerAnimated:NO];
}

我也尝试了这些，但没有成功：

self.tabBarController.selectedIndex = 1;  

任何人都

[self.tabBarController setSelectedIndex:1];

可以帮助我并解释我所缺少的内容吗？

Answer 1

发生这种情况有以下原因。

您已将 ViewController 作为子视图添加到窗口中，无需添加 SubView，因为您已经将该 ViewController 呈现为 ModalViewController。

请尝试如下。

-(BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{    
//-- Insert a delay of 5 seconds before the splash screen disappears
[NSThread sleepForTimeInterval:3.0];        

// Set the tab bar controller as the window's root view controller and display.
self.window.rootViewController = self.tabBarController;

// Set StartView to load first
StartViewController *startViewController = [[StartViewController alloc] initWithNibName:@"StartView" bundle: nil];
//[window addSubview: [startViewController view]]; no need to add subView here
[window makeKeyAndVisible];

[self.tabBarController presentModalViewController:startViewController animated:NO];
[startViewController release];
return YES;

}

-(IBAction) toSecondView:(id)sender
{
// Show status bar
[[UIApplication sharedApplication] setStatusBarHidden:NO withAnimation:UIStatusBarAnimationNone];
//create delegate's class object for accessing tabBarController
 AppDelegate* delegate=(AppDelegate*)[[UIApplication sharedApplication]delegate];
 //instead of [(UITabBarController *)self.parentViewController setSelectedIndex:1];
 //delegate.tabBarController your tabBarControler at which you have added viewController
[delegate.tabBarController setSelectedIndex:1];

[self dismissModalViewControllerAnimated:NO];

}