tgt1.首先，新建一个继承UITabBarController的类MainTabBarController(ps：名字可修改)。右键NewFile->cocoa touch class->next

2.新建TabBarController 的ViewControllers（这里新建两个继承与UIViewController的类，这里分别取名为FirstViewController和SecondViewController）

新建类的过程跟上边一样。

3.在MainViewController.m文件中实现如下代码

#import "MainViewController.h"

#import "FirstViewController.h"

#import "SecondViewController.h"

@interface MainViewController ()

@end

@implementation MainViewController

- (void)viewDidLoad {

      [super viewDidLoad];

      [self addSubViewController];

// Do any additional setup after loading the view.

}

-(void)addSubViewController{

      FirstViewController *FVC = [[FisrtViewController alloc]init];

      UINavigationController *FNC = [[UINavigationController alloc]initWithRootViewController:FVC];

      //初始化tabbaritem的标题和图标

      UITabBarItem *FTB = [[UITabBarItem alloc]initWithTitle:@"activity" image:[UIImage imageNamed:    @"activity.png"] tag:0];

        saNC.tabBarItem = FTB;

        SecondViewController *SVC = [[SecondViewController alloc]init];

        UINavigationController *SNC = [[UINavigationController alloc]initWithRootViewController:SVC];

        UITabBarItem *STB = [[UITabBarItem alloc] initWithTitle:@"help" image:[UIImage imageNamed:@"help.png"] tag:1];

      SNC.tabBarItem=STB;

      NSArray *controllerArray = @[FNC,SNC];

      [self setViewControllers:controllerArray animated:YES];

}

4.在AppDelegate.m文件中的第一个方法，添加如下代码：

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

    // Override point for customization after application launch.

    MainViewController *mainvc = [[MainViewController alloc]init];

    self.window.backgroundColor = [UIColor whiteColor];

    self.window.rootViewController = mainvc;

    return YES;

}

5.在Target->general中改变Main Interface，将Main改为LaunchScreen(点击工程文件可进入)：

工程文件

6.运行效果如下：