在iOS iPhone中难以显示选项卡视图

Question

I'm new to iOS dev and I have a program that begins by presenting the user a view. This view has two buttons, and depending on which the user clicks, a different tab view will be displayed. The tab view is displayed like this:

betaAppDelegate* delegate = (betaAppDelegate*)[[UIApplication sharedApplication]delegate];
acquireData *ac_view = (acquireData*)[[acquireData alloc] init];
[delegate.window addSubview:ac_view.view];

[self.view removeFromSuperview];
[self dealloc];

The tab view is ac_view.view. When I run the application in the simulator, instead of displaying my tab view with three tabs, it displays a white screen with a thin black bar (empty tab dock) on the bottom. It's encouraging to at least see something be displayed! But I've been trying without success for a while to get it to display my tabs. The .xib file looks correct. It has the three tabs at the bottom, and each of the three tabs say in the interface builder that they're loaded from xxxxxxx, so the linking appears correct...

Thank you!

Answer 1

I'm going to presume you're using the UITabBarController.

You can either set one up by adding the tabs in interface builder and then setting which xibs the individual tabs load up. It sounds like you have done this. After that there is no code you need to write to get the tab bar working to switch between your three view controllers.

You can also set up the TabBarController programatically.

This would be the programmatic way and would go into you application delegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{
UITabBarController * aTabBarController = [[UITabBarController alloc] init];
NSArray * array = [[NSArray alloc] initWithObjects:controller1, controller2, controller3, nil];
[aTabBarController setViewControllers:array animated:NO];
[array release];

self.window.rootViewController = aTabBarController;
[self.window makeKeyAndVisible];
[aTabBarController release];
return YES;
}

You would then see a tab bar with three tabs that correspond to controller1, 2 and 3 (your custom view controllers)

To set the icon and text and things its as easy as reading the documentation and seeing

Tab bar items are configured through their corresponding view controller. To associate a tab bar item with a view controller, create a new instance of the UITabBarItem class, configure it appropriately for the view controller, and assign it to the view controller's tabBarItem property.

Just a final word of warning in Objective C you should never call dealloc yourself. Dealloc is called by the system when an objects retain count reaches 0. Read into how to retain and release objects to get the hang of how this all works.

Good luck