Changing Uipageviewcontroller's Page Programmatically Doesn't Update the Uipagecontrol

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

to update your UIPageControl indicator, you need to implement one data source method of UIPageViewController (the UIPageViewControllerDataSource method) :

-(NSInteger)presentationIndexForPageViewController:(UIPageViewController *)pageViewController

This method is responsible for updating the page control indicator (when you use UIPageViewController). You only need to return the currentpage value in this method. The Method gets called by default when you use/make a call for setViewControllers on your custom UIPageViewController.

So the chunk of code that you need to write is:

- (void)scrollToNext
{
    UIViewController *current = self.viewControllers[0];
    NSInteger currentIndex = [self.model indexForViewController:current];
    UIViewController *nextController = [self.model viewControllerForIndex:++currentIndex];
    if (nextController) {
        NSArray *viewControllers = @[nextController];
       // This changes the View Controller and calls the presentationIndexForPageViewController datasource method
       [self setViewControllers:viewControllers
                   direction:UIPageViewControllerNavigationDirectionForward
                    animated:YES
                  completion:nil];
}

- (NSInteger)presentationIndexForPageViewController:(UIPageViewController *)pageViewController
{
    return currentIndex;
}

Hope this solves your problem. :)

Is it possible to Turn page programmatically in UIPageViewController?

Yes it is possible with the method:

- (void)setViewControllers:(NSArray *)viewControllers 
                 direction:(UIPageViewControllerNavigationDirection)direction 
                  animated:(BOOL)animated 
                completion:(void (^)(BOOL finished))completion;`

That is the same method used for setting up the first view controller on the page. Similar, you can use it to go to other pages.

Wonder why viewControllers is an array, and not a single view controller?

That's because a page view controller could have a "spine" (like in iBooks), displaying 2 pages of content at a time. If you display 1 page of content at a time, then just pass in a 1-element array.

An example in Swift:

pageContainer.setViewControllers([displayThisViewController], direction: .Forward, animated: true, completion: nil)

Programmatically-added page control disappears when setting view controllers after setup

Create a single UIPageControl that you put in the WalkthroughRootViewController and update it when you navigate the pages - don't create a page control for each child.

Try not to use extensions to override methods - it can cause you trouble - see this blog entry.

Reloading Views in UIPageViewController

After a long time and after wasting a support ticket with Apple, I decided to go with another approach.

In my Storyboard I created 2 different navigation controllers, one for each case (if there are somethings and if there aren't any), and I have an initial view Controller that, on viewDidAppear, instantiates one of the two and presents it. This way, I make sure that the entire navigation controller gets reloaded correctly.

UINavigationController *nc;

if ([Settings somethings].count)
{
    nc = [self.storyboard instantiateViewControllerWithIdentifier:@"NavigationController"];
}
else
{
    nc = [self.storyboard instantiateViewControllerWithIdentifier:@"NoSomethingNavigationController"];
}

self.nc = nc;

[self presentViewController:nc animated:NO completion:nil];

How to change position of UIPageControl in iOS =8.0?

Yes, you can add custom page controller for that.

self.pageControl = [[UIPageControl alloc] initWithFrame:CGRectMake(0, self.view.frame.size.height - 50, self.view.frame.size.width, 50)]; // your position

[self.view addSubview: self.pageControl];

then remove

- (NSInteger)presentationCountForPageViewController:(UIPageViewController *)pageViewController

and

- (NSInteger)presentationIndexForPageViewController:(UIPageViewController *)pageViewController

Then add another delegate method:

- (void)pageViewController:(UIPageViewController *)pageViewController willTransitionToViewControllers:(NSArray<UIViewController *> *)pendingViewControllers
 {
     PageContentViewController *pageContentView = (PageContentViewController*) pendingViewControllers[0];
     self.pageControl.currentPage = pageContentView.pageIndex;
 }

UIPageViewController, how do I correctly jump to a specific page without messing up the order specified by the data source?

Programming iOS6, by Matt Neuburg documents this exact problem, and I actually found that his solution feels a little better than the currently accepted answer. That solution, which works great, has a negative side effect of animating to the image before/after, and then jarringly replacing that page with the desired page. I felt like that was a weird user experience, and Matt's solution takes care of that.

__weak UIPageViewController* pvcw = pvc;
[pvc setViewControllers:@[page]
              direction:UIPageViewControllerNavigationDirectionForward
               animated:YES completion:^(BOOL finished) {
                   UIPageViewController* pvcs = pvcw;
                   if (!pvcs) return;
                   dispatch_async(dispatch_get_main_queue(), ^{
                       [pvcs setViewControllers:@[page]
                                  direction:UIPageViewControllerNavigationDirectionForward
                                   animated:NO completion:nil];
                   });
               }];

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