hide status bar on iOS 7, add this snippet on the root view controller.

hideStatusBar.m

- (void)viewDidLoad 
{
	[super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
	
	if ([self respondsToSelector:SELE(setNeedsStatusBarAppearanceUpdate)]) { //iOS 7
        [self setNeedsStatusBarAppearanceUpdate];
    } else {
        [[UIApplication sharedApplication] setStatusBarHidden:YES withAnimation:UIStatusBarAnimationFade];
    }
}

// overwrite this Method
- (BOOL)prefersStatusBarHidden 
{
    return YES;
}