Simple Tab-bar Controller

CDBViewController.h

#import <UIKit/UIKit.h>@interface CDBViewController : UIViewController {NSString *message;}@property(nonatomic, retain) NSString *message;- (id)initWithMessage:(NSString *)theMessage andImage:(UIImage *)Image;@end

CDBViewController.m

#import "CDBViewController.h"#import "CDBView.h"@implementation CDBViewController@synthesize message;- (id)initWithMessage:(NSString *)theMessage andImage:(UIImage *)image {    self = [super initWithNibName:nil bundle:nil];    if (self) {        self.message = theMessage;self.tabBarItem.image = image;    }    return self;}- (void)loadView {CDBView *theView = [[CDBView alloc] initWithFrame:[UIScreen mainScreen].applicationFrame];theView.backgroundColor = [UIColor whiteColor];theView.myController = self;theView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;self.view = theView;[theView release];}@end

The tabBarItem is declared in UIViewController class as follows:
@property(nonatomic, readonly, retain) UITabBarItem *tabBarItem

The UITabBarItem class is a subclass of UIBarItem. It inherits from its superclass theimage andtitle properties. The default value of theimage is nil. However, thetitle value, if not set, is set to the value of theview controller's title property.

CDBView.h

#import <UIKit/UIKit.h>@class CDBViewController;@interface CDBView : UIView {CDBViewController *myController;}@property(nonatomic, assign) CDBViewController *myController;@end

CDBView.m

#import "CDBView.h"#import "CDBViewController.h"@implementation CDBView@synthesize myController;- (void)drawRect:(CGRect)rect {    [myController.message drawAtPoint:CGPointMake(80, 30) withFont:[UIFont systemFontOfSize:50]];}- (void)dealloc {    [super dealloc];}@end

@interface TabBar2AppDelegate : NSObject <UIApplicationDelegate> {    UIWindow *window;CDBViewController *viewController1, *viewController2,*viewController3,  *viewController4, *viewController5,*viewController6;UITabBarController *tabBarController;}@property (nonatomic, retain) UIWindow *window;@end

#import "TabBar2AppDelegate.h"@implementation TabBar2AppDelegate@synthesize window;#pragma mark -#pragma mark Application lifecycle- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {        // Override point for customization after application launch.self.window = [[[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds]    autorelease];viewController1 = [[CDBViewController alloc] initWithMessage:@"item1" andImage:[UIImage imageNamed:@"item1.png"]];viewController1.title = @"item1";viewController2 = [[CDBViewController alloc] initWithMessage:@"item2" andImage:[UIImage imageNamed:@"item2.png"]];viewController2.title = @"item2";viewController3 = [[CDBViewController alloc] initWithMessage:@"item3" andImage:[UIImage imageNamed:@"item3.png"]];viewController3.title = @"item3";viewController4 = [[CDBViewController alloc] initWithMessage:@"item4" andImage:[UIImage imageNamed:@"item4.png"]];viewController4.title = @"item4";viewController5 = [[CDBViewController alloc] initWithMessage:@"item5" andImage:[UIImage imageNamed:@"item5.png"]];viewController5.title = @"item5";viewController6 = [[CDBViewController alloc] initWithMessage:@"item6" andImage:[UIImage imageNamed:@"item6.png"]];viewController6.title = @"item6";tabBarController = [[UITabBarController alloc] init];tabBarController.viewControllers = [[NSArray alloc] initWithObjects:viewController1,viewController2,viewController3,viewController4,viewController5,viewController6,nil];[self.window addSubview:tabBarController.view];    [self.window makeKeyAndVisible];    return YES;}- (void)dealloc {[viewController1 release];[viewController2 release];[viewController3 release];[viewController4 release];[viewController5 release];[viewController6 release];[tabBarController release];[window release];    [super dealloc];}@end

The viewControllers is declared inUITabBarController class as follows:

@property(nonatomic, copy) NSArray *viewControllers

Some comments on tab-bat conrollers

The More list

The more item is managed by a navigation controller that can be accessed using the tab-bar controller's propertymoreNavigationController, Which is declared as :
@property(nonatomic, readonly) UINavigationController *moreNavigationController

Badge (displayed in item's up-right corner)
@property(nonatomic, copy) NSString *badgeValue
viewController1.tabBarItem.badgeValue = @"3";

Selected controller

@property(nonatomic, assgin) UIViewController *selectedViewController;
tabBarController.selectedViewController = viewController3;

@property(nonatomic) NSUInteger selectedIndex

customization

if you have more than five items managed by the tab-bar controller, you can give the user ability to rearrage the postion of these controllers.

@property(nonatomic, copy) NSArray *customizableViewController

tabBarController.customizableViewController = [[NSArray alloc] initWithObjects:viewController1,viewController2,viewController6,nil];