gistfile1.m

// Assuming again pageViewController.viewControllers returns the
// NSArray of UIViewControllers and the object at index 0 is the
// current view controller---which has a property idx indicating
// the current page.

- (NSInteger)presentationIndexForPageViewController:(UIPageViewController *)pageViewController {
    int currentPage = [[pageViewController.viewControllers objectAtIndex:0] idx];
    return currentPage;
}

// MAX_PAGES is the total # of pages.

- (NSInteger)presentationCountForPageViewController:(UIPageViewController *)pageViewController {
    return MAX_PAGES;
}