CGRect frame = CGRectMake（0，0，320，48）；

 UIView *v = [[UIView alloc]initWithFrame:frame];

 [v setBackgroundColor:[[UIColor allor]initWithRed:70.0/255.0

 green:65.0/255.0

 blue:62.0/255.0

 alpha:1.0]];

 [rootController.tabBar insertSubview:v atIndex:0];

 [v release];

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    

// Override point for customization after application launch.
    FirstViewController *mainViewController = [[FirstViewController alloc] init];
    SecondViewController *searchViewController = [[SecondViewController alloc]init];
    ThirdViewController *myselfViewController = [[ThirdViewController alloc]init];
    ForthViewController *settingViewController = [[ForthViewController alloc]init];

//隐藏tabbar所留下的黑边（试着注释后你会知道这个的作用）
    mainViewController.hidesBottomBarWhenPushed = true;
    searchViewController.hidesBottomBarWhenPushed = true;
    myselfViewController.hidesBottomBarWhenPushed = true;
    settingViewController.hidesBottomBarWhenPushed = true;

    mainViewController.title = @"首页";
    searchViewController.title = @"搜索";
    myselfViewController.title = @"我";
    settingViewController.title = @"设置";

//创建导航
    UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:mainViewController ];
    UINavigationController *nav1 = [[ UINavigationController alloc] initWithRootViewController:searchViewController];
    UINavigationController *nav2 = [[UINavigationController alloc] initWithRootViewController:myselfViewController];
    UINavigationController *nav3 = [[UINavigationController alloc]initWithRootViewController:settingViewController];

//创建数组
    NSMutableArray *controllers = [[NSMutableArray alloc]init];
    [controllers addObject:nav];
    [controllers addObject:nav1];
    [controllers addObject:nav2];
    [controllers addObject:nav3];

//创建tabbar
    tabBarController = [[ CustomTabBar alloc] init];
    tabBarController.viewControllers = controllers;
    tabBarController.selectedIndex = 0;

//显示
    [self.window addSubview:tabBarController.view];
    [self.window makeKeyAndVisible];


return YES;
}

#import "Ivan_UITabBar.h"


@implementation Ivan_UITabBar
@synthesize currentSelectedIndex;
@synthesize buttons;

- (void)viewDidAppear:(BOOL)animated{
   
    slideBg = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"slide"]];
    [self hideRealTabBar];
    [self customTabBar];
}

- (void)hideRealTabBar{
   
for(UIView *view in self.view.subviews){
   
if([view isKindOfClass:[UITabBar class]]){
   
            view.hidden = YES;
break;
        }
    }
}

- (void)customTabBar{
   
    UIView *tabBarBackGroundView = [[UIView alloc] initWithFrame:self.tabBar.frame];
    tabBarBackGroundView.backgroundColor = [UIColor grayColor];
//创建按钮
    int viewCount = self.viewControllers.count > 5 ? 5 : self.viewControllers.count;
    self.buttons = [NSMutableArray arrayWithCapacity:viewCount];
double _width = 320 / viewCount;
//    NSLog(@"%d",viewCount);
    double _height = self.tabBar.frame.size.height;
for (int i = 0; i < viewCount; i++) {
   
        UIViewController *v = [self.viewControllers objectAtIndex:i];
        UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
        btn.frame = CGRectMake(i*_width, 0, _width, _height);
        ;
        btn.tag = i;
//        NSLog(@"%@",v.tabBarItem.image);
        ;
        UILabel *titleLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, _height-20, _width, _height-30)];
        titleLabel.backgroundColor = [UIColor clearColor];
        titleLabel.text = v.tabBarItem.title;
        titleLabel.textAlignment = 1;
        titleLabel.textColor = [UIColor whiteColor];
        ;
        [titleLabel release];
        [self.buttons addObject:btn];
        [tabBarBackGroundView addSubview:btn];
    }
    [self.view addSubview:tabBarBackGroundView];
    [tabBarBackGroundView addSubview:slideBg];
    [self.view insertSubview:tabBarBackGroundView atIndex:0];
    [tabBarBackGroundView release];
    [self selectedTab:[self.buttons objectAtIndex:0]];
}

- (void)selectedTab:(UIButton *)button{
   
if (self.currentSelectedIndex == button.tag) {
   
        [[self.viewControllers objectAtIndex:button.tag] popToRootViewControllerAnimated:YES];
    }
    self.currentSelectedIndex = button.tag;
    self.selectedIndex = self.currentSelectedIndex;
    [self performSelector:@selector(slideTabBg:) withObject:button];
}

- (void)slideTabBg:(UIButton *)btn{
   
    [UIView beginAnimations:nil context:nil];  
    [UIView setAnimationDuration:0.20];  
    [UIView setAnimationDelegate:self];
    slideBg.frame = btn.frame;
    [UIView commitAnimations];
}