Use of tabbarcontroller

Make a simple one tabbarController There are three steps ：

//1. Create label controller
UITabBarController *tab = [[UITabBarController alloc] init];

//2. Create the corresponding word controller 
ViewController *firstVc = [[ViewController alloc] init];
firstVc.tabBarItem.title = @" Hello ";
firstVc.tabBarItem.image = [UIImage imageNamed:@" Adorable adorable "];

SecondViewController *secondVC = [[SecondViewController alloc] init];
secondVC.tabBarItem.title = @"hello";
secondVC.tabBarItem.image = UIImageName(@" memory ");

//3. Add to controller 

NSArray *array = @[firstVc,secondVC];
tab.viewControllers = array;
self.window.rootViewController = tab;
[self.window makeKeyAndVisible];

In this case , A simple tabbarController It's coming out.

Generally, yes Tabbar It also carries navgationBar So today I will also navgationbar Add in, too Look at the code below ：
//1. Create label controller
UITabBarController *tab = [[UITabBarController alloc] init];

//2. Create the corresponding word controller 
ViewController *firstVc = [[ViewController alloc] init];
//2.1 It's added here nav Of title
firstVc.navigationItem.title = @" Hello ";
firstVc.tabBarItem.title = @" Hello ";
firstVc.tabBarItem.image = [UIImage imageNamed:@" Adorable adorable "];
//2.2 Initialization here nav And set rootVC
UINavigationController *firstNav = [[UINavigationController alloc] initWithRootViewController:firstVc];

SecondViewController *secondVC = [[SecondViewController alloc] init];
secondVC.navigationItem.title = @"hello";
secondVC.tabBarItem.title = @"hello";
secondVC.tabBarItem.image = UIImageName(@" memory ");
UINavigationController *secondNav = [[UINavigationController alloc] initWithRootViewController:secondVC];

//3. Add to controller 
// Particular attention ： Manage a group of controllers （ Display up to five , More than five include five all in more modules , And it can be edited sequentially by dragging ）;

// NSArray *array = @[firstVc,secondVC];
// Replace the controller in the array Just like the
NSArray *array = @[firstNav,secondNav];
tab.viewControllers = array;
self.window.rootViewController = tab;
[self.window makeKeyAndVisible];
This is just a low-level implementation Next encapsulation