scrollToItem isn't working in my CollectionView?

Question

Why scrollToItem isn't working in my CollectionView? I want to work scrollToItem on EnabledID. So what's a problem and how fixed it?

Code:

var dataArray = NSMutableArray() // dataArray is has a data from Database
var EnabledID = Int()

EnabledID = UserDefaults.standard.integer(forKey: "EnabledID")
    
if EnabledID == 0 {
        
    EnabledID = 1
    UserDefaults.standard.set(1, forKey: "EnabledID")
        
} else {
    if EnabledID < dataArray.count {
        let index = NSIndexPath(item: EnabledID, section: 0)
        self.myCollectionView.scrollToItem(at: index as IndexPath, at: .centeredVertically, animated: true)
    }
}

notice that, if you have dynamic size cells, scrolling will not work properly for some reason: http://www.openradar.me/37836568 https://github.com/airbnb/MagazineLayout/issues/68 — Zaporozhchenko Oleksandr, May 27 '21 at 15:16

Ramkumar Paulraj · Accepted Answer · 2023-01-24T11:12:42.597

56

Try this code...

Objective-C

[collectionView setDelegate:self];
[collectionView reloadData];
[collectionView layoutIfNeeded];
[collectionView scrollToItemAtIndexPath:[NSIndexPath indexPathForItem:0 inSection:0] atScrollPosition:UICollectionViewScrollPositionTop animated:YES];

Swift - 4.x

collectionView.delegate = self
collectionView.reloadData()
collectionView.layoutIfNeeded()
collectionView.scrollToItem(at: IndexPath(item: 0, section: 0), at: .top, animated: true)

When the scroll direction is horizontal you need to use left,right or centeredHorizontally.

top is for the vertical direction.

collectionView.scrollToItem(at: index, at: .top, animated: true)

edited Jan 24 '23 at 11:12

answered Jun 20 '18 at 12:26

Ramkumar Paulraj

1,841
2
20
40

1

"When the scroll direction is horizontal you need to use left,right or centeredHorizontally. " - this comment just saved me an hour. Thank you so much! =D – baskInEminence Jul 07 '20 at 04:03
@baskInEminence nice to hear that !!! – Ramkumar Paulraj Jan 19 '22 at 11:46

score 34 · Answer 2 · answered Sep 22 '20 at 12:43

the best way i found to do this is to not use scrollToItem but to get the CGRect of the index and then make that visible.

 let rect = self.collectionView.layoutAttributesForItem(at: IndexPath(row: 5, section: 0))?.frame
 self.collectionView.scrollRectToVisible(rect!, animated: false)

score 10 · Answer 3 · answered Dec 10 '19 at 03:32

My problem is a little weird. My iPhone 6/7/8 works fine, but iPhone X or 11 cannot scroll to my expected position. My original code is :

collectionView.reloadData()
collectionView.scrollToItem(at: IndexPath(item: 10, section: 0), at: .top, animated: true)

After I add collectionView.layoutIfNeeded(). Problem solves on my iPhone X and 11.

collectionView.reloadData()
collectionView.layoutIfNeeded()
collectionView.scrollToItem(at: IndexPath(item: 10, section: 0), at: .top, animated: true)

This answer is inspired by @ram. He should get the credit. Add this answer is just to emphasize the difference between different iPhones. So people can search their answer quicker.

collectionView.layoutIfNeeded(), this saved my time. Thank you — Tharanga, Aug 05 '21 at 10:58

score 5 · Answer 4 · answered Jul 17 '22 at 12:37

I use such workaround:

collectionView.isPagingEnabled = false
collectionView.scrollToItem(
    at: /* needed IndexPath */,
    at: .centeredHorizontally,
    animated: true
)
collectionView.isPagingEnabled = true

I've found such solution in several posts here and here.

omid pourpanah · Answer 5 · 2021-05-11T06:48:34.943

3

try this.it is work for me

func scrollToIndex(index:Int) {
     let rect = self.collectionView.layoutAttributesForItem(at:IndexPath(row: index, section: 0))?.frame
     self.collectionView.scrollRectToVisible(rect!, animated: true)
 }

edited May 11 '21 at 06:48

answered May 11 '21 at 06:43

omid pourpanah

79
3

Federico Picci · Answer 6 · 2021-02-24T15:39:25.507

It won't work because contentSize is probably (0,0). If you not wish to use layoutIfNeeded() (because maybe you could be performing some undesirable an unnecessary stuff there), you should calculate it yourself (assuming your data is loaded, and the view did layout).

Swift 5.2

    collection.contentSize = CGSize(width: collection.bounds.width * CGFloat(items.count), height: collection.bounds.height)
    collection.scrollToItem(at: IndexPath(row: startingIndex, section: 0), at: .left, animated: false)

score 1 · Answer 7 · answered Jun 20 '18 at 12:15

Try this for horizontal collection view

var isViewDidLayoutCallFirstTime = true


override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()
    guard self.isViewDidLayoutCallFirstTime else {return}
    self.isViewDidLayoutCallFirstTime = false
    self.collectionView.collectionViewLayout.collectionViewContentSize // It will required to re calculate collectionViewContentSize in internal method 
    let indexpath = IndexPath(item: self.currentIndex, section: 0)

    self.collectionView.scrollToItem(at: indexpath, at: UICollectionViewScrollPosition.centeredHorizontally, animated: false)

}

score 1 · Answer 8 · edited Nov 17 '20 at 18:58

1

I've encountered this issue on iOS 14.x and Xcode 12.x.

The solution that worked for me was to use:

collectionView.scrollRectToVisible(rect, animated: true)

edited Nov 17 '20 at 18:58

shim

9,289
12
69
108

answered Nov 17 '20 at 12:19

Andrei Traciu

267
2
2

score 1 · Answer 9 · answered May 30 '22 at 02:17

1

collectionView.collectionViewLayout.invalidateLayout()
collectionView.scrollToItem(at: indexPath, at: .centeredHorizontally, animated: true)
collectionView.collectionViewLayout.invalidateLayout()

answered May 30 '22 at 02:17

Ilya

11
1

score 0 · Answer 10 · answered Sep 25 '20 at 10:55

0

In my case .centeredVertically had no effect and was failing quietly. .centeredHorizontally fixed it

answered Sep 25 '20 at 10:55

Anton Tropashko

5,486
5
41
66

score 0 · Answer 11 · answered Aug 02 '21 at 16:51

 var scrollImg: Int = 0

override func viewDidLoad() {
    super.viewDidLoad()
    _ = Timer.scheduledTimer(timeInterval: 2, target: self, selector: #selector(autoScroll), userInfo: nil, repeats: true)

}

   @objc func autoScroll() {
    
    let totalCount = imageArray.count-1
    
    if scrollImg == totalCount{
        scrollImg = 0
    }else {
        scrollImg += 1
    }
    
    DispatchQueue.main.async {
        let rect = self.listOfViewsCollectionViews.layoutAttributesForItem(at: IndexPath(row: self.scrollImg, section: 0))?.frame
        if self.scrollImg == 0{
            self.listOfViewsCollectionViews.scrollRectToVisible(rect!, animated: false)
        }else {
            self.listOfViewsCollectionViews.scrollRectToVisible(rect!, animated: true)
        }
    }
}

score 0 · Answer 12 · answered Feb 22 '23 at 21:17

if you want to chance scrollToItem in viewDidLoad, it's won't work

do it in viewDidLayoutSubviews or viewDidAppear

override func viewDidLayoutSubviews() {
             collectionView.scrollToItem(at: IndexPath(row: index, section: 0), at: .centeredHorizontally, animated: true)
    }

or

    override func viewDidAppear(_ animated: Bool) {
        collectionView.scrollToItem(at: IndexPath(row: index, section: 0), at: .centeredHorizontally, animated: true)
    }

Vishal Vaghasiya · Answer 13 · 2020-12-14T11:10:55.880

-3

Use This

self.messageCV.reloadData()
let indexPath = IndexPath(row: 0, section: 0)
self.messageCV.scrollToItem(at: indexPath, at: .bottom, animated: true) // .top

edited Dec 14 '20 at 11:10

answered Jun 20 '18 at 11:18

Vishal Vaghasiya

4,618
3
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40

Are you sure your code is correct?? Because get me warning (Value 'cell' was defined but never used; consider replacing with boolean test, Replace 'let cell = self.myCollectionView.cellForItem(at: indexPath as IndexPath) as? CollectionViewCell' with '(self.myCollectionView.cellForItem(at: indexPath as IndexPath) as? CollectionViewCell) != nil'). And your condition `if let cell = self.myCollectionView...` is empty !! – developer1996 Jun 20 '18 at 11:30
use this code , because same error solution In my project – Vishal Vaghasiya Jun 20 '18 at 11:30
this if. condition is checking only – Vishal Vaghasiya Jun 20 '18 at 11:31
I checked and print in console (`not able to cast collection view cell class to CollectionViewCell`) – developer1996 Jun 20 '18 at 11:34
collection view issue in your side , outlet , add class name , – Vishal Vaghasiya Jun 20 '18 at 11:35
Thank you for your suggested – developer1996 Jun 20 '18 at 11:42
after 6:30 clock to not solve error to give me team id , I will try to solution your code – Vishal Vaghasiya Jun 20 '18 at 11:44
I don't have team and 6:30 the time of which city ? – developer1996 Jun 20 '18 at 11:48
OK, do u have email or any account of social network ? – developer1996 Jun 20 '18 at 11:52
Is same name in stack overflow ? – developer1996 Jun 20 '18 at 11:55
I followed you, check your account – developer1996 Jun 20 '18 at 12:00
OK, I'm waiting you – developer1996 Jun 20 '18 at 12:24

scrollToItem isn't working in my CollectionView?

13 Answers13