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ios - UICollectionView auto scroll to cell at IndexPath

Before loading the collection view user sets the number of image in the array of collection view. All of the cells don't fit on the screen. I have 30 cells and only 6 on the screen.

The question: How to scroll to the cell with desired image automatically at the load of UICollectionView?

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New, Edited Answer:

Add this in viewDidLayoutSubviews

SWIFT

override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()
    let indexPath = IndexPath(item: 12, section: 0)
    self.collectionView.scrollToItem(at: indexPath, at: [.centeredVertically, .centeredHorizontally], animated: true)
}

Normally, .centerVertically is the case

ObjC

-(void)viewDidLayoutSubviews {
   [super viewDidLayoutSubviews];
    NSIndexPath *indexPath = [NSIndexPath indexPathForItem:12 inSection:0];
   [self.collectionView scrollToItemAtIndexPath:indexPath atScrollPosition:UICollectionViewScrollPositionCenteredVertically | UICollectionViewScrollPositionCenteredHorizontally animated:NO];
}

Old answer working for older iOS

Add this in viewWillAppear:

[self.view layoutIfNeeded];
[self.collectionView scrollToItemAtIndexPath:indexPath atScrollPosition:UICollectionViewScrollPositionCenteredVertically animated:NO];

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