Changing UIPageViewController's page programmatically doesn't update the UIPageControl

Question

In my custom UIPageViewController class:

- (id)initWithCoder:(NSCoder *)aDecoder
{
    self = [super initWithCoder:aDecoder];
    if (self) {
           


        

Answer 1

As mentioned in accepted answer, you need to implement

- (NSInteger)presentationIndexForPageViewController:(UIPageViewController *)pageViewController

But for me it was enough to use it like this:

Objective-C:

- (NSInteger)presentationIndexForPageViewController:(UIPageViewController *)pageViewController {
    // The selected item reflected in the page indicator.
    return [self.controllers indexOfObject:[pageViewController.viewControllers firstObject]];
}

Swift 3+:

func presentationIndex(for pageViewController: UIPageViewController) -> Int {
        guard let index = viewControllers?.index(of: (pageViewController.viewControllers?.first)!) else { return 0 }
        return index
}

Without the need to remember the current index. Where self.controllers is an NSArray of UIViewControllers displayed in given UIPageViewController. I'm not sure how exactly your BSTCMWelcomingPageViewModel works, but it should be easy to adjust.