在UIViewController中添加UITabBar

// 错误代码

// Main Controller 
@implementation MainViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    HomeViewController *homeViewController =   [[HomeViewController alloc] init];
    // 此时呈现包含UITabBar的控制器
    [self presentViewController:homeViewController animated:NO completion:nil];
}


// 正确代码
-(void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
    HomeViewController *homeViewController = [[HomeViewController alloc] init];
    [self presentViewController:homeViewController animated:NO completion:nil];
}