How does iOS set the font color of the status bar on all interfaces to white and ios font color?

How does iOS set the font color of the status bar on all interfaces to white and ios font color?

Step 1: Add a field in info. plist: view controller-base status bar to NO

Step 2: Add the following in didfinishlaunchingwitexceptions of the AppDelegate class:

If (IOS7) {// determine whether the value is greater than or equal to IOS7

// [[UIApplication sharedApplication] setStatusBarStyle: UIStatusBarStyleLightContentanimated: NO];

[[UIApplication sharedApplication] setStatusBarStyle: UIStatusBarStyleLightContent];

}