UIPageViewController: get the currentPage

Question

I have been struggling with this issue for the last few days and after all this juggling I have figured out that all I need is the current Index from the datasource method to update with current visible page number

I have this UIPageViewController datasource method and I need to use the current index to get the current visible page for delegate method previousViewControllers transitionCompleted:(BOOL)completed

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController
   viewControllerAfterViewController:(UIViewController *)viewController { 
    NSString *path = [[NSBundle mainBundle] pathForResource:@"pages" ofType:@"pdf"];

    NSURL *pdfurl = [NSURL fileURLWithPath:path];
    PDFDocument = CGPDFDocumentCreateWithURL((__bridge CFURLRef)pdfurl);

    contentViewController = [[ContentViewController alloc] initWithPDFAtPath:path];

    currentIndex = [modelArray indexOfObject:[(ContentViewController *)viewController page]];

    if (currentIndex == totalPages - 1) {  
        return nil;
    }

    contentViewController.page = [modelArray objectAtIndex:currentIndex + 1];

    return contentViewController;
}

I'm confused about how to write the current index statement from datasource method into delegate method to update current visible page.

- (void)pageViewController:(UIPageViewController *)pageViewController didFinishAnimating:(BOOL)finished previousViewControllers:(NSArray *)previousViewControllers transitionCompleted:(BOOL)completed{

    if (!completed)
    {
        return;
    }

    //currentIndex = [[self.pageViewController.viewController lastObject]];  
    currentIndex = [self indexOfObject:contentViewController];

    [self displaycurrentIndex:currentIndex];
    //self.pageControl.currentPage = currentIndex;
}

How can I correct this?

score 29 · Answer 1 · edited Jul 07 '15 at 09:08

29

It looks like you should be able to get the current index with:

ContentViewController *viewController = [self.pageViewController.viewControllers lastObject];
currentIndex = [modelArray indexOfObject:[viewController page]];

edited Jul 07 '15 at 09:08

Daniel

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answered Jul 20 '13 at 22:09

Wain

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i have written it like this but getting parse issue expected identifier currentIndex = [modelArray indexOfObject:[ContentViewController *)viewController page]]; – user1120133 Jul 20 '13 at 22:23
Your snippet pasted is missing. `(` in the cast. – Wain Jul 20 '13 at 22:26
not working but tried this currentIndex=contentViewController.page; but getting 1 of 20 and when turning page over showing 128393777 of 20 – user1120133 Jul 20 '13 at 22:41
You'll need to show the code and the definition of what the page is and your source array. – Wain Jul 20 '13 at 22:53
if i try with your answer then getting 1 of 20 then after turning page over -2147483648 of 20 – user1120133 Jul 20 '13 at 22:59
solved it tried this and now it is working currentIndex = [modelArray indexOfObject:contentViewController.page]; [self displaycurrentIndex:currentIndex]; – user1120133 Jul 20 '13 at 23:03
Thanks for your time and help. Appreciate it. – user1120133 Jul 20 '13 at 23:05
I found this to be the most accurate method of getting the current page index. For a custom UIPageControl, placing this in the didFinishingAnimating... delegate method was the best way to update a it. There is need to keep track of the current index with a property as well. – barnabus Apr 29 '15 at 10:16

score 20 · Answer 2 · answered Oct 09 '15 at 23:17

20

for swift:

func pageViewController(pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool){
        let pageContentViewController = pageViewController.viewControllers![0] as! ViewController
        let index = pageContentViewController.pageIndex

}

answered Oct 09 '15 at 23:17

sof98789

1,051
11
17

Cool solution. Works in every situation .Can you explain the 2nd line of your code ? – G.Abhisek Dec 28 '15 at 10:49
4

When the user swipes back, you will not have the current index – jaytrixz Jan 05 '16 at 05:48
5

Value of type 'ViewController' has no member 'pageIndex' – N. Der Jan 29 '19 at 21:32

score 8 · Answer 3 · edited Mar 11 '15 at 11:40

if you implement ModelController (as in Apple example), use it's method indexOfViewController

- (void)pageViewController:(UIPageViewController *)pageViewController didFinishAnimating:(BOOL)finished previousViewControllers:(NSArray *)previousViewControllers transitionCompleted:(BOOL)completed {
    myDataViewController *currentView = [pageViewController.viewControllers objectAtIndex:0];
    NSInteger currentIndex = [_modelController indexOfViewController:currentView];
    [self displayPageNumber:currentIndex];
}

Mandeep Singh · Answer 4 · 2017-10-04T17:14:55.717

I am facing the same issue on pageViewController, everytime i swipe my pageViewController it calls my delegate twice and am not able to find the issue. And my array is dynamic so i want the proper index value from pageController. First of all set the delegate of your pageViewController. Like this :-

self.pageViewController.delegate = self;

And then add this delegate method to your class

- (void)pageViewController:(UIPageViewController *)pageViewController didFinishAnimating:(BOOL)finished previousViewControllers:(NSArray *)previousViewControllers transitionCompleted:(BOOL)completed
{
if (completed) {
    NSInteger currentIndex = ((PageContentViewController *)self.pageViewController.viewControllers.firstObject).pageIndex;

    NSLog(@"%ld",(long)currentIndex);
}
}

PageContentViewController is the class where you are showing your data of pageViewController.

Run your project and if everything is working fine, you will get your index value. PageIndex is the Integer value for getting the current index. Hope it will helps you.

Thanks

Mandeep Singh

score 5 · Answer 5 · answered Feb 13 '19 at 15:30

My approach is quite simple:

When the page (controller) is instantiated I pass in the page index, which at this point is known.
Then in the delegate call below, iff the transition finished, I obtain the controller currently shown and cast it to my custom page class, before I fetch and update the currentPage with the associated page index.

To keep things simple I setup the data source and delegate to be the WalkThroughController which embeds the page view controller.

extension WalkThroughController: UIPageViewControllerDelegate {

    func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {

        guard finished, let currentPageController = pageViewController.viewControllers?.last as? WalkThroughPageViewController else {
            return
        }

        self.currentPage = currentPageController.pageIndex
    }

}

The take away point is to set the page index of the pages when they are created in the data source. With this approach it is very straight forward to retrieve it later.

The best and quite simple decision which just works. – devshok Jul 07 '20 at 12:48 — devshok, Jul 07 '20 at 12:48

score 4 · Answer 6 · edited Jun 23 '14 at 09:15

4

Implement Delegate Method

- (void)pageViewController:(UIPageViewController *)pageViewController didFinishAnimating:(BOOL)finished previousViewControllers:(NSArray *)previousViewControllers transitionCompleted:(BOOL)completed{
        NSLog(@"Current Page = %@", pageViewController.viewControllers);

        UIViewController *currentView = [pageViewController.viewControllers objectAtIndex:0];

             if ([currentView isKindOfClass:[FirstPageViewController class]]) {
                 NSLog(@"First View");
            }
            else if([currentView isKindOfClass:[SecondPageViewController class]]){
                 NSLog(@"Second View");
            }
            else if([currentView isKindOfClass:[ThirdViewController class]]){
                  NSLog(@"Third View");
            }
 }

//pageViewController.viewControllers always return current visible View ViewController

edited Jun 23 '14 at 09:15

Daniel

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answered Apr 01 '14 at 11:34

Avinash Kashyap

861
10
16

3

I dont know who upvoted this but I dont think that this is the correct solution. What do I do in my case because I have 12 Pages and I am loading the same view controller with different data. – iOS_Developer May 12 '15 at 22:21
Hey, you can use tag for differentiate view controller. – Avinash Kashyap May 26 '15 at 09:48
This doesn't solve the problem if you are reusing a controller – tf.alves Jul 06 '15 at 14:30

score 2 · Answer 7 · answered Oct 06 '15 at 04:31

To get the current index you'll have to do the following:

-(void)pageViewController:(UIPageViewController *)pageViewController didFinishAnimating:(BOOL)finished previousViewControllers:(NSArray *)previousViewControllers transitionCompleted:(BOOL)completed {


   NSUInteger index = [self.viewControllers indexOfObject: [pageViewController.viewControllers lastObject]];

   NSLog(@"INDEX: %lu",(unsigned long)index);

}

score 2 · Answer 8 · answered Dec 11 '15 at 23:09

I struggled with this too and none of the other solutions worked for me, but was finally able to solve it using a delegate method:

First in PageContentViewController.h Add the following property:

@property NSUInteger pageIndex;

Second create a delegate protocol in the PageContentViewController (not the PageViewController).

In PageContentViewController.h:

 @protocol PageContentDelegate <NSObject>

 - (void)sendBackPageIndex:(NSUInteger)index;

@end

@interface LKFPageContentViewController : (UIViewController)

@property (weak, nonatomic) id<LKFPageContentDelegate> delegate;
....
@end

Third in PageContentViewController.m perform delegate method in viewDidAppear

//Note that this must be done in viewDidAppear not viewDidLoad
- (void)viewDidAppear:(BOOL)animated {

[super viewDidAppear:YES];

[self.delegate sendBackPageIndex:self.pageIndex];

Fourth, in PageViewController.m implement the delegate method

#pragma mark - PageContentView delegate methods

- (void)sendBackPageIndex:(NSUInteger)index {

    //This is where you get your current page index
    NSUInteger currentPageIndex = index;
}

Fifth, in PageViewController.m make sure you pass the pageIndex value and set the delegate

- (PageContentViewController *)viewControllerAtIndex:(NSUInteger)index {

    if (([self.arrayOfTitles count] == 0) || (index >= [self.arrayOfTitles count])) {
        return nil;
    }

    // Create a new view controller and pass suitable data.
    PageContentViewController *pageContentViewController = [self.storyboard instantiateViewControllerWithIdentifier:@"PageContentViewController"];

    pageContentViewController.pageIndex = index;

    pageContentViewController.delegate = self;

    return pageContentViewController
}

score 2 · Answer 9 · answered Jan 19 '16 at 06:11

I have solved this problem like this:

* Parent View Controller (PageViewController) *

@interface MyParentPageViewController () <UIPageViewControllerDataSource>


@property (nonatomic, assign) NSUInteger currentPageIndex;

@end

@implementation MyParentPageViewController

- (void)viewDidLoad 
{
  [super viewDidLoad];

  MyChildViewController *rootChildViewController = [MyChildViewController controllerWithPageIndex:self.currentPageIndex];
  [self setViewControllers:@[rootChildViewController]
             direction:UIPageViewControllerNavigationDirectionForward
              animated:YES completion:nil];
  self.dataSource = self;
}

#pragma mark - Page View Controller DataSource
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController 
viewControllerAfterViewController:(MyChildViewController *)viewController
{
  if (viewController.pageIndex == self.sourceArray.count - 1) {
    return nil;
  }
  MyChildViewController *vc = [MyChildViewController controllerWithPageIndex:viewController.pageIndex + 1];
  return vc;
}

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController
viewControllerBeforeViewController:(CHHomeDetailTableController *)viewController 
{
  if (viewController.pageIndex == 0) {
    return nil;
  }
  MyChilViewController *vc = [MyChildViewController controllerWithPageIndex:viewController.pageIndex - 1];
  return vc;
}


@end

* Child View Controller *

@implementation MyChildViewController
- (void)viewWillAppear
{
    MyParentPageViewController *parentPageViewController = (MyParentPageViewController *)self.parentViewController;
    parentViewController.currentPageIndex = self.pageIndex;
}
@end

For example, the parentPageViewController's currentPageIndex is 10 , or some other values, when your swipe right, parentViewController.currentPageIndex will be 9, if 0 , nothing happened; If you swipe left, parentPageViewController.currentPageIndex will be 11, if the showing controller.view is the last, nothing happened too.

score 0 · Answer 10 · answered Apr 15 '15 at 13:33

You can try this. This will give you current page.

    - (void)pageViewController:(UIPageViewController *)pageViewController didFinishAnimating:(BOOL)finished previousViewControllers:(NSArray *)previousViewControllers transitionCompleted:(BOOL)completed
{
    UIViewController * viewController = [previousViewControllers lastObject];

    NSUInteger previousPage = [(PageContentViewController *)viewController index];

    NSUInteger currentPage = previousPage+1;
}

When the user swipes back, this will increment the current page when it shouldn't — jaytrixz, Jan 05 '16 at 05:45

score 0 · Answer 11 · answered Jan 05 '16 at 05:51

This is how I determine the current page index whether the user swipes to the left or to the right and whether he changes his swipe direction gesture in the middle of swiping. Just make sure you have a pageIndex property in your view controller to store the index:

func pageViewController(pageViewController: UIPageViewController, willTransitionToViewControllers pendingViewControllers: [UIViewController]) {
        let currentPageIndex = (pendingViewControllers.last! as! ViewController).pageIndex!
    }

score 0 · Answer 12 · answered Jul 31 '17 at 20:30

There is no nice way to do this but I think the most reliable way is to observe UIPageViewControllerDelegate calls:

var index: Int
var proposedViewController: UIViewController?

// MARK: UIPageViewControllerDelegate

func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
    guard let proposedViewController = proposedViewController,
        let index = myViewControllers?.index(of: proposedViewController) else {
            return
    }
    self.index = index
}

func pageViewController(_ pageViewController: UIPageViewController, willTransitionTo pendingViewControllers: [UIViewController]) {
    guard pendingViewControllers.count == 1,
        let proposedViewController = pendingViewControllers.first else {
        return
    }
    self.proposedViewController = proposedViewController
}

UIPageViewController: get the currentPage

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