CODEWITHSUNDEEP
iosobjective-cuiscrollviewuicollectionviewnsindexpath
Avijit Das
Avijit Das

Reputation: 300

How we can get visible Cell IndexPath when a UICollectionView Loads its data initially

Is there any way that we can get indexPathsForVisibleItems when a UICollectionView loads its data initially . Basically I want all cell indexPaths which are currently visible on the screen. I am getting that in scrollViewDidScroll using below code. 

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    [self LoadVisibleItems];

  }

-(void)LoadVisibleItems
{
   NSArray* visibleCellIndex = self.myCollectionView.indexPathsForVisibleItems;

  NSArray *sortedIndexPaths = [visibleCellIndex   sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
    NSIndexPath *path1 = (NSIndexPath *)obj1;
    NSIndexPath *path2 = (NSIndexPath *)obj2;
    return [path1 compare:path2];
}];



NSIndexPath* newFirstVisibleCell = [sortedIndexPaths firstObject];
NSIndexPath* newLastVisibleCell = [sortedIndexPaths lastObject];


}

Upvotes: 2

Views: 8040

Answers (2)

KTang
KTang

Reputation: 350

Try

[self.collectionView layoutIfNeeded];
NSArray *ary = collectionView.visibleCells;
for (UICollectionViewCell *cell in ary) {
    NSIndexPath *path = [collectionView indexPathForCell:cell];
    NSLog(@"indexPath of cell: %d - %d", (int)path.section, (int)path.row);
}

or use

-(void)collectionView:(UICollectionView *)collectionView willDisplayCell:(UICollectionViewCell *)cell forItemAtIndexPath:(NSIndexPath *)indexPath{

}

Upvotes: 2

dopcn
dopcn

Reputation: 4218

Correct me if I misunderstand your question

If you load collectionView from storyboard

- (void) viewDidLoad {
    [super viewDidLoad];
    NSArray* visibleCellIndex = self.myCollectionView.indexPathsForVisibleItems;
}

If you init collectionView by code after some view addSubview collectionView do

NSArray* visibleCellIndex = self.myCollectionView.indexPathsForVisibleItems;

Upvotes: 6

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