注意这里是：Tab Bar 不是Tab Bar Controller. Tab bar是继承UIView，所以可以添加到ViewController里。是View就可以add到另一个View上去。Tab Bar Controller是新建View视图。

XX.h 里需要定义UITabBar，并且要引用协议 UITabBarDelegate.

@interface LoginViewController :UIViewController<UITabBarDelegate>

{

    UITabBar *tabbar;

}

@property (nonatomic, retain) UITabBar *tabbar;

XX.m

@synthesize tabbar;

- (void)viewDidLoad

{

    //加载Tab bar

    CGRect footFrame = CGRectMake(0, 420, 320, 60);

    tabbar = [[UITabBar alloc]initWithFrame:footFrame];

    UITabBarItem *item1 = [[UITabBarItem alloc]initWithTabBarSystemItem:1 tag:0];

    UITabBarItem *item2 = [[UITabBarItem alloc]initWithTabBarSystemItem:2 tag:1];

    NSArray *items = [[NSArray alloc]initWithObjects:item1,item2, nil];

    [tabbar setItems:items animated:YES];

    [item1 release];

    [item2 release];

    [items release];

    [self.view addSubview:tabbar];

    tabbar.delegate = self;//指定其代理方法，不然方法不起作用

    [tabbar release]; 

}

- (void)tabBar:(UITabBar *)tabbar didSelectItem:(UITabBarItem *)item 

{

    NSLog(@"Selected is %d",item.tag);

    NSString *msg = [[NSString alloc]initWithFormat:@"selected is %d",item.tag];

    UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"a" message:msg delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];

    [alert show];

    [msg release];

    [alert release];

}

学习笔记：Tab Bar 控件使用详解