Some basic settings of UITabBarController

Add UITabBarController using code

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    
    ViewController *vc1 = [[ViewController alloc] init];
    
    UserGuideViewController *vc2 = [[UserGuideViewController alloc] init];
    
    UITabBarController *tabBarController = [[UITabBarController alloc] init];
    tabBarController.viewControllers = [[NSArray alloc] initWithObjects:vc1, vc2, nil];
    
    for(int i=0; i<tabBarController.tabBar.items.count; i++) {
        UITabBarItem *item = [tabBarController.tabBar.items objectAtIndex:i];
        
        item.title = [NSString stringWithFormat:@" %d",i];
        
        NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:[UIColor grayColor],UITextAttributeTextColor, nil];
        [item setTitleTextAttributes:dict forState:UIControlStateNormal];
        
        NSDictionary *dict2 = [NSDictionary dictionaryWithObjectsAndKeys:[UIColor redColor],
                               UITextAttributeTextColor,nil];
        [item setTitleTextAttributes:dict2 forState:UIControlStateSelected];
    }
    
    self.window.rootViewController = tabBarController;
    [self.window makeKeyAndVisible];
    
    return YES;
}

 
Change the background color of the TabBar
method one:

UIView *bgView = [[UIView alloc] initWithFrame:self.tabBar.bounds];
bgView.backgroundColor = [UIColor redColor];
[self.tabBar insertSubview:bgView atIndex:0];

Method Two:

CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, [[UIColor redColor] CGColor]);
CGContextFillRect(context, rect);
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

self.tabBar.backgroundImage = image;

 
Change TabBarItem's (selected/unselected) background image
Method 1, change the global:

UIImage *bgImage = [UIImage imageNamed:@"Image1"];
[[UITabBar appearance] setBackgroundImage:[bgImage resizableImageWithCapInsets:UIEdgeInsetsZero]];
[[UITabBar appearance] setSelectionIndicatorImage:[UIImage imageNamed:@"Image2"]];

Method two, change the specific:

[self.tabBar setBackgroundImage:[UIImage imageNamed:@"GuideImage1"]];
[self.tabBar setSelectionIndicatorImage:[UIImage imageNamed:@"GuideImage2"]];

 
Change TabBarItem's selected and unselected icons

- (void)viewDidLoad {
    [super viewDidLoad];

    UIImage *carIcon = [UIImage imageNamed:@"CarIcon"];
    UIImage *grayCarIcon = [UIImage imageNamed:@"GrayCarIcon"];

    
    ViewController *vc1 = [[ViewController alloc] init];
    UITabBarItem *item1 = [[UITabBarItem alloc] initWithTitle:@" A" image:carIcon tag:0];
    item1.selectedImage = grayCarIcon;
    vc1.tabBarItem = item1;
    
    
    UserGuideViewController *vc2 = [[UserGuideViewController alloc] init];
    UITabBarItem *item2 = [[UITabBarItem alloc] initWithTitle:@" B" image:carIcon tag:0];
    item2.selectedImage = grayCarIcon;
    vc2.tabBarItem = item2;
    
    self.viewControllers = [[NSArray alloc] initWithObjects:vc1, vc2, nil];
    
    [self setSelectedViewController:vc2];
}

 
Change text color of TabBarItem

UITabBarItem *item = self.tabBar.items[0];

NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:[UIColor grayColor],UITextAttributeTextColor, nil];
[item setTitleTextAttributes:dict forState:UIControlStateNormal];

NSDictionary *dict2 = [NSDictionary dictionaryWithObjectsAndKeys:[UIColor redColor],
                       UITextAttributeTextColor,nil];
[item setTitleTextAttributes:dict2 forState:UIControlStateSelected];