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?
New, Edited Answer:
Add this in viewDidLayoutSubviews
-(void)viewDidLayoutSubviews {
[super viewDidLayoutSubviews];
[self.collectionView scrollToItemAtIndexPath:indexPath atScrollPosition:UICollectionViewScrollPositionCenteredVertically animated:NO];
}
Old answer working for older iOS
Add this in viewWillAppear :
[self.view layoutIfNeeded];
[self.collectionView scrollToItemAtIndexPath:indexPath atScrollPosition:UICollectionViewScrollPositionCenteredVertically animated:NO];
I've found that scrolling in viewWillAppear may not work reliably because the collection view hasn't finished it's layout yet; you may scroll to the wrong item.
I've also found that scrolling in viewDidAppear will cause a momentary flash of the unscrolled view to be visible.
And, if you scroll every time through viewDidLayoutSubviews, the user won't be able to manually scroll because some collection layouts cause subview layout every time you scroll.
Here's what I found works reliably:
- (void)viewDidLayoutSubviews {
[super viewDidLayoutSubviews];
// If we haven't done the initial scroll, do it once.
if (!self.initialScrollDone) {
self.initialScrollDone = YES;
[self.collectionView scrollToItemAtIndexPath:self.myInitialIndexPath
atScrollPosition:UICollectionViewScrollPositionRight animated:NO];
}
}
I totally agree with the above answer. The only thing is that for me the solution was set the code in viewDidAppear
viewDidAppear
{
[self.collectionView scrollToItemAtIndexPath:indexPath atScrollPosition:UICollectionViewScrollPositionCenteredVertically animated:YES];
}
When I used the viewWillAppear the scrolling didn't work.
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