Badge on the tab bar item did not show
===

In my app, the badge value of my tabBar item is set in the `AppDelegate.m`, as following:

**AppDelegate.m**

    - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
    {
     ...
     UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
     UITabBarController *tabBarController = [storyboard instantiateViewControllerWithIdentifier:@"tabBarController"]; 
     [[tabBarController.tabBar.items objectAtIndex:4] setBadgeValue:@"1"];
    ...
    }
    
    - (void)applicationWillEnterForeground:(UIApplication *)application
    {
     ...
     UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
     UITabBarController *tabBarController = [storyboard instantiateViewControllerWithIdentifier:@"tabBarController"]; 
     [[tabBarController.tabBar.items objectAtIndex:4] setBadgeValue:@"2"];
    ...
    
    }
    
    - (void)applicationDidBecomeActive:(UIApplication *)application
    {
     ...
     UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
     UITabBarController *tabBarController = [storyboard instantiateViewControllerWithIdentifier:@"tabBarController"]; 
     [[tabBarController.tabBar.items objectAtIndex:4] setBadgeValue:@"3"];
    ...
    }

Problem is: The badge value is always "1". Why the badge value set in both `applicationWillEnterForeground:` and `applicationDidBecomeActive:` will never appear? If i did not set badge value in `application: didFinishLaunchingWithOptions:`, there is no badge shown there.