help with page control

[cinek]

I'm trying to get pagecontrol to work. Right now I can scroll to the 2nd page, but the background is not changing (im changing the background to make sure it works fine). When I use pageControl to flip through pages, the background changes fine. I think I need to call pageTurning in scrollViewDidScroll but adding [self pageTurningage]; does not work

this is what I have atm:

static int kNumberOfPages = 2;

#import "AppDelegate.h"

@implementation AppDelegate

@synthesize window = _window;
@synthesize pageControl, scrollView, viewControllers;

-(IBAction)changePage:(id)sender
{
    pageControlUsed = YES;
}

-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
    pageControlUsed = NO;
}

-(void)scrollViewDidScroll:(UIScrollView *)sender
{
    if(pageControlUsed){
        return;
    }
    
    CGFloat pageWidth = scrollView.frame.size.width;
    int page = floor((scrollView.contentOffset.x - pageWidth / 2)/pageWidth) + 1;
    pageControl.currentPage = page;
    
}

-(void)pageTurning:(UIPageControl *)pageController{
    NSInteger nextPage = [pageController currentPage];
    
    switch (nextPage) {
        case 0:
            scrollView.backgroundColor = [UIColor blueColor];
            break;
        case 1:
            scrollView.backgroundColor = [UIColor redColor];
            
        default:
            break;
    }
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    scrollView.contentSize = CGSizeMake(scrollView.frame.size.width * kNumberOfPages, scrollView.frame.size.height);
    scrollView.delegate = self;
    
    [pageControl addTarget:self action:@selector(pageTurning:) forControlEvents:UIControlEventValueChanged];
    
    pageControl.currentPage = 0;
    
    [self pageTurning:pageControl];
    
    //self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    //self.window.backgroundColor = [UIColor whiteColor];
    [self.window makeKeyAndVisible];
    return YES;

any ideas?