UITabBarController中自定义UITabBar

1.创建多个视图控制器，放如UITabBarController中

AViewController  *aa = [[AViewController alloc] init];
    UINavigationController* ayNav = [[UINavigationController alloc]initWithRootViewController:aa];
    
    BViewController  *bb = [[BViewController alloc] init];
    UINavigationController* bNav = [[UINavigationController alloc]initWithRootViewController:bb];

    CViewController  *cc = [[CViewController alloc] init];
    UINavigationController* cNav = [[UINavigationController alloc]initWithRootViewController:cc];

    DViewController  *dd = [[DViewController alloc] init];
    UINavigationController* dNav = [[UINavigationController alloc]initWithRootViewController:dd];
     2.初始化tabbar
    UITabBarController *tabBarController = [[UITabBarController alloc]init];
    tabBarController.delegate=self;
    tabBarController.viewControllers=[[NSArray alloc]initWithObjects:ayNav,bNav,cNav,dNav,nil];

  3.获取到tabBarController中的tabBar，在从tabBar中获取到每个items

UITabBar *tabBar = tabBarController.tabBar;
    UITabBarItem *aTabBarItem = [tabBar.items objectAtIndex:0];
    UITabBarItem *bTabBarItem = [tabBar.items objectAtIndex:1];
    UITabBarItem *cTabBarItem = [tabBar.items objectAtIndex:2];
    UITabBarItem *dTabBarItem = [tabBar.items objectAtIndex:3];

  4. 设置tabBar中items的标题

aTabBarItem.title = @"aaa";
    bTabBarItem.title = @"bbb";
    cTabBarItem.title = @"ccc";
    dTabBarItem.title = @"ddd";

   5.设置tabBar中items的图片

[aTabBarItem setFinishedSelectedImage:[UIImage imageNamed:@"aa_selected.png"] withFinishedUnselectedImage:[UIImage imageNamed:@"aa.png"]];
    [bTabBarItem setFinishedSelectedImage:[UIImage imageNamed:@"bb_selected.png"] withFinishedUnselectedImage:[UIImage imageNamed:@"bb.png"]];
    [cTabBarItem setFinishedSelectedImage:[UIImage imageNamed:@"cc_selected.png"] withFinishedUnselectedImage:[UIImage imageNamed:@"cc.png"]];
    [dTabBarItem setFinishedSelectedImage:[UIImage imageNamed:@"dd_selected.png"] withFinishedUnselectedImage:[UIImage imageNamed:@"dd.png"]];

    6.设置tabBar的背景图片

// Change the tab bar background
    UIImage* tabBarBackground = [UIImage imageNamed:@"tabbarbg.png"];
    [[UITabBar appearance] setBackgroundImage:[tabBarBackground resizableImageWithCapInsets:UIEdgeInsetsZero]];
    [[UITabBar appearance] setSelectionIndicatorImage:[UIImage imageNamed:@"tabbar_selected.png"]];

   7.改变tabBar中items上字体的颜色

// Change the title color of tab bar items
    [[UITabBarItem appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
                                                       [UIColor grayColor], UITextAttributeTextColor,
                                                       nil] forState:UIControlStateNormal];
    UIColor *titleHighlightedColor = [UIColor colorWithRed:153/255.0 green:192/255.0 blue:48/255.0 alpha:1.0];
    [[UITabBarItem appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
                                                       titleHighlightedColor, UITextAttributeTextColor,
                                                       nil] forState:UIControlStateHighlighted];

   8.将tabBarController加入window中

self.window.rootViewController = tabBarController;
   [self.window makeKeyAndVisible];