UITabBar view programmatically chosen on tap - ios

Question

I had a navigation controller based application. And I decided to use tab bars in my application.
When the user presses at a certain tab bar item I want to display a certain view controller - and I want programmatically in my code choose which one to display.
I tried to add in the Interface Builder a navigation controller into my tab bar, but viewWillAppear of its view controller is not being called.
How can I implement this feature?

Answer 1

I don't know if it's the "right way", but here's how I usually do this with three tabs.
- (void)initControls {
// Create the window.
[self setWindow:[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]];
// Create Tab Bar.
tabCon = [[UITabBarController alloc] init];
// Local array variable that holds the viewcontrollers.
// Capacity corresponds to the number of VC's
NSMutableArray *localVCArray = [[NSMutableArray alloc] initWithCapacity:3];
MyFirstViewController *oneViewController = [[MyFirstViewController alloc] init];
UINavigationController *oneNavCon = [[UINavigationController alloc] initWithRootViewController:oneViewController];
[localVCArray addObject:oneNavCon];
[oneViewController release];
[oneNavCon release];
MySecondViewController *twoViewController = [[MySecondViewController alloc] init];
UINavigationController *twoNavCon = [[UINavigationController alloc] initWithRootViewController:twoViewController];
[localVCArray addObject:twoNavCon];
[twoViewController release];
[twoNavCon release];
MyThirdViewController *threeViewController = [[MyThirdViewController alloc] init];
UINavigationController *threeNavCon = [[UINavigationController alloc] initWithRootViewController:threeViewController];
[localVCArray addObject:threeNavCon];
[threeViewController release];
[threeNavCon release];
// Set the tab bars array of view controllers to the localVCArray
[[self tabCon] setViewControllers:localVCArray animated:YES];
// Release the localVCArray, all of its contents are now retained by tabCon.
[localVCArray release];
// Add controls to window and show.
[window addSubview:[tabCon view]];
[window makeKeyAndVisible];
}
In the init method each viewController you can do something like:
[[self tabBarItem] setImage:[dataSource tabConImg]];
[[self tabBarItem] setTitle:[dataSource name]];
[[self navigationItem] setTitle:[dataSource navConName]];
To set the icon used in the tab bar, the title in the tab bar, and the title of you navigation item.