Get current controller with InfiniteDataSource

[mimmo00]

Hi, congratulations for the framework!
I'm using the InfiniteDataSource. I can set the variables of controller during the initial setting.

`extension ContainerViewController: PagingViewControllerInfiniteDataSource {

func pagingViewController<T>(_ pagingViewController: PagingViewController<T>, viewControllerForPagingItem pagingItem: T) -> UIViewController {
    let calendarItem = pagingItem as! CalendarItem
    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    let currentController = storyboard.instantiateViewController(withIdentifier: "CollectionViewController") as! CollectionViewController
    currentController.currentDate = calendarItem.date
    currentController.delegate = self
    return currentController
}

...`

How can I communicate with the current controller later?

Thanks

[rechsteiner]

Hi @mimmo00! You can get the currently selected view controller using the delegate:

func pagingViewController<T>(
    _ pagingViewController: PagingViewController<T>,
    didScrollToItem pagingItem: T,
    startingViewController: UIViewController?,
    destinationViewController: UIViewController,
    transitionSuccessful: Bool)

Does that work for you?

[mimmo00]

Thanks @rechsteiner for the answer. I use it to get the scroll of the pages. Two questions:

• do I need to cast the destionationViewController into CollectionViewController, right?
• I have to use this delegate even if I don’t scroll?

Thanks a lot!

[rechsteiner]

do I need to cast the destionationViewController into CollectionViewController, right?

Yeah, that's correct

I have to use this delegate even if I don’t scroll?

Yes, this delegate should also be called if the user selects the items in the menu 🙂

[mimmo00]

Thanks!

[mimmo00]

Hi @rechsteiner , unfortunately the delegate is not called on startup. it is only called when you scroll or select a menu item. So I have not found a solution yet :(

[rechsteiner]

Hi 👋 If you need the initially selected view controller you should be able to read that directly on the page view controller like this:

pagingViewController.pageViewController.selectedViewController

Does that work for you?

[mimmo00]

Thanks, but in ViewDidAppear it is nil

... pagingViewController.select(pagingItem: CalendarItem(date: Date())) if (pagingViewController.pageViewController.selectedViewController == nil) { print("NIL") }

I need to replicate this on start:

`
func pagingViewController(_ pagingViewController: PagingViewController, didScrollToItem pagingItem: T, startingViewController: UIViewController?, destinationViewController: UIViewController, transitionSuccessful: Bool) where T : PagingItem, T : Comparable, T : Hashable {

    currentController = destinationViewController as! CollectionViewController

}
}
`

Thanks a lot

[mimmo00]

@rechsteiner maybe the problem is that I'm using a subclass of PagingViewController?

class ResizedPagingViewController : PagingViewController<CalendarItem> { override func loadView() { view = ResizedPagingView( options: options, collectionView: collectionView, pageView: pageViewController.view) } }

[rechsteiner]

Using a subclass shouldn't be a problem. The view controller is not added before viewDidAppear. Are you sure you are checking there and not in viewDidLoad? I just tried adding this to the CalendarExample and it logs the selected view controller just fine:

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    print(pagingViewController.pageViewController.selectedViewController)
  }

Optional(<CalendarExample.CalendarViewController: 0x7fb74a42fc00>)

[mimmo00]

Yes, I tried everything inside viewDidAppear
For now I solved this dirty way (inside viewDidAppear ):

DispatchQueue.main.asyncAfter(deadline: .now() + 1, execute: {

                self.pagingViewController.select(pagingItem: CalendarItem(date: Date()))

            })

Thanks!

[rechsteiner]

Can you try calling select(pagingItem:) in viewDidLoad then printing selectedViewController in viewDidAppear?

[mimmo00]

Yes, I tried again now. If I'm logged in, it crash because it loads the listing from server. If I am not logged in, the empty status appears without problems. Probably it is some strange logic of the listing to cause the error, not the library :)