Infinite paging, Smart auto layout, Interface of similar to UIKit.

Hi. I'm having an issue with reloadData() because it's resetting the scrollview back to the first indexPath. What i'm expecting for reloadData() is the same with tableView/collectionView that it will stay at the current indexPath and just reload the other visible cells. Is this possible? TIA

So.. What I want is a PagingView with 2 images. Without infinite scrolling.

I followed your example and made ImagePagingCell extending PagingViewCell (basically just a UIImageView that fills the entire nib like the one in your demo). But the problem is that instead of only having 2 images I have 4, the 2 images duplicated.

Here's some code:

// Inside viewDidLoad
self.pagingView.dataSource = self
self.pagingView.delegate = self
self.pagingView.infinite = false

// then...
func pagingView(pagingView: PagingView, numberOfItemsInSection section: Int) -> Int {
   return 2
}   

func pagingView(pagingView: PagingView, cellForItemAtIndexPath indexPath: NSIndexPath) -> PagingViewCell {
       pageControl.currentPage = indexPath.row
       let cell = pagingView.dequeueReusableCellWithReuseIdentifier("ImagePagingViewCell")
       var url : String = ""
       if indexPath.row == 0 {
          url = (self.data?.img0)!
       } else if indexPath.row == 1 {
           url = (self.data?.img1)!
       }
       let imageURL = NSURL(string: "\(Const.URL_BASE_IMAGE)\(url)")
       if let cell = cell as? ImagePageViewCell {
           cell.imageView.af_setImageWithURL(imageURL!)
       }
       return cell
}

Any ideas why I'm getting 4 pages instead of 2?

Thanks

After I adjusted the code... Test Case infinite == false && itemToShow.count == 2 infinite == true && itemToShow.count == 2 infinite == false && itemToShow.count >2 infinite == true && itemToShow.count > 2 Result Every cases works fine. Thanks

the thing is when I call reloadData and tries to get the visiblecells it's empty because layoutSubviews hasn't be called yet. so with this it will force layoutSubviews right away. Let me know if this is okay.

When you have only one or two images and the infinite loop is set to true, it's showing only one image and bug when you swipe right. (with more than 2 images work fine)

Don't stop if the indexPath doesn't exist or out of bound. My use case for this if I want to clear out the scrollView I return 0 to numberOfItems in dataSource and tries to reloadData(). It should just clear out the scrollview

Let me know if you have any good solution for this.

self.pageView.delegate = self
self.pageView.dataSource = self
self.pageView.infinite = false

func numberOfSectionsInPagingView(pagingView: PagingView) -> Int {
    return 1
}

Total 2 item

func pagingView(pagingView: PagingView, numberOfItemsInSection section: Int) -> Int {
    return 2
}

Displaying the second item

func indexPathOfStartingInPagingView(pagingView: PagingView) -> NSIndexPath? {
    return NSIndexPath(forRow: 1, inSection: 0)
}

Hi

When I set infinite looping flag to false.

Now scroll the page to 1/2/3... from 0 manually, assume the index comes to 2. Then use the api pagingView.scrollToPosition(.center, indexPath: IndexPath(item: 0, section: 0), animated: false)

Ok, now the index is 0, but this time infinite scrolling is turned on again. I can scroll to 4 directly, just like the infinite looping flat fails.

Here is the code

class DemoViewController: UIViewController {
    @IBOutlet weak var pagingView: PagingView!
        
    var colors: [UIColor] = ["0", "1", "2", "3", "4", "5"].map({ _ in UIColor.randomColor })

    override func viewDidLoad() {
        super.viewDidLoad()

        pagingView.dataSource = self
        pagingView.delegate = self
        pagingView.pagingMargin = 0
        pagingView.pagingInset = 0
        pagingView.infinite = false
        pagingView.showsHorizontalScrollIndicator = false
        
        let nib = UINib(nibName: "DemoViewCell", bundle: nil)
        pagingView.registerNib(nib, forCellWithReuseIdentifier: "DemoViewCell")
        
    }
    
    @IBAction func scrollManually(_ sender: Any) {
        pagingView.scrollToPosition(.center, indexPath: IndexPath(item: 0, section: 0), animated: false)
    }
    
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    
}

extension DemoViewController: PagingViewDataSource, PagingViewDelegate {
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        if let centerCell = pagingView.visibleCenterCell() {
            title = "\(centerCell.indexPath.item)"
        }
    }
    
    func pagingView(_ pagingView: PagingView, numberOfItemsInSection section: Int) -> Int {
        return colors.count
    }
    
    func pagingView(_ pagingView: PagingView, cellForItemAtIndexPath indexPath: IndexPath) -> PagingViewCell {
        let cell = pagingView.dequeueReusableCellWithReuseIdentifier("DemoViewCell")
        if let cell = cell as? DemoViewCell {
            let color = colors[indexPath.item]
            cell.backgroundColor = color
            cell.label.text = "\(indexPath.item)"
        }
        return cell
    }
}

Here is the demo video: https://user-images.githubusercontent.com/16531533/170958760-dee49e3e-9e80-4b70-a840-4aebf9c72849.mov

Version PagingView (0.5.1) SIGTRAP 0x00000000019d4b84

Crashed: com.apple.main-thread
0  libswiftCore.dylib             0x19d4b84 globalinit_33_FD9A49A256BEB6AF7C48013347ADC3BA_func6 + 100612
1  PagingView                     0x14467f8 PagingView.reloadContentView() (PagingView.swift:388)
2  PagingView                     0x1447288 PagingView.layoutSubviews() (PagingView.swift:439)
3  PagingView                     0x1447634 @objc PagingView.layoutSubviews() (PagingView.swift)
4  UIKit                          0x2102f483 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 1224
5  QuartzCore                     0x1ec87cb7 -[CALayer layoutSublayers] + 126
6  QuartzCore                     0x1ec7bd77 CA::Layer::layout_if_needed(CA::Transaction*) + 354
7  UIKit                          0x210431a7 -[UIView(Hierarchy) layoutBelowIfNeeded] + 1176
8  MyApp              0x1cdde4 specialized APagingBaseCell.setData(_:page:) (APagingBaseCell.swift:81)
9  MyApp              0x3719bc specialized AListView.collectionView(_:cellForItemAt:) (AListView.swift:154)
10 MyApp              0x3705a0 @objc AListView.collectionView(_:cellForItemAt:) (AListView.swift)
11 UIKit                          0x218b3851 -[UICollectionView _createPreparedCellForItemAtIndexPath:withLayoutAttributes:applyAttributes:isFocused:notify:] + 420
12 UIKit                          0x210935e1 -[UICollectionView _createPreparedCellForItemAtIndexPath:withLayoutAttributes:applyAttributes:] + 42
13 UIKit                          0x210917f7 -[UICollectionView _updateVisibleCellsNow:] + 4076
14 UIKit                          0x2108c3d7 -[UICollectionView layoutSubviews] + 398
15 UIKit                          0x2102f483 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 1224
16 QuartzCore                     0x1ec87cb7 -[CALayer layoutSublayers] + 126
17 QuartzCore                     0x1ec7bd77 CA::Layer::layout_if_needed(CA::Transaction*) + 354
18 QuartzCore                     0x1ec7bc05 CA::Layer::layout_and_display_if_needed(CA::Transaction*) + 16
19 QuartzCore                     0x1ec0a839 CA::Context::commit_transaction(CA::Transaction*) + 320
20 QuartzCore                     0x1ec28fdb CA::Transaction::commit() + 578
21 QuartzCore                     0x1ec29b2f CA::Transaction::observer_callback(__CFRunLoopObserver*, unsigned long, void*) + 162
22 CoreFoundation                 0x1bdbb803 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 20
23 CoreFoundation                 0x1bdb9a55 __CFRunLoopDoObservers + 282
24 CoreFoundation                 0x1bdba017 __CFRunLoopRun + 1358
25 CoreFoundation                 0x1bd0d1af CFRunLoopRunSpecific + 470
26 CoreFoundation                 0x1bd0cfd1 CFRunLoopRunInMode + 104
27 GraphicsServices               0x1d4b7b41 GSEventRunModal + 80
28 UIKit                          0x21095a53 UIApplicationMain + 150
29 MyApp              0x110ae4 main (A.swift:44)
30 libdyld.dylib                  0x1b4fa4eb start + 2

@KyoheiG3

when having a UIRefreshControl assigned to the PagingView, this refreshControl appears on one of the pages next the the center page. So my guess that the wrong page is centered...

Using this values of parameters

pagingView.pagingMargin = 0
pagingView.pagingInset = 0
pagingView.infinite = false

the first three pages are displayed only.

Steps to reproduce:

1. Open "PagingViewExample" project
2. Set the above values of parameters in the "DemoViewControler" class
3. Run project
4. Open "Demo" tab