Select items programmatically in UICollectionView

Question

I have a UICollectionViewController:

- (NSInteger)collectionView:(UICollectionView *)collectionView 
     numberOfItemsInSection:(NSInteger)sect         


        

Answer 1

NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
[self.districtTableview selectRowAtIndexPath:indexPath animated:YES scrollPosition:UITableViewScrollPositionTop];
[self tableView:weakSelf.districtTableview didSelectRowAtIndexPath:indexPath];

I used the above method in tableview, and it worked.

Answer 2

I think you are missing this method from the UICollectionView Class Reference:

- (void)selectItemAtIndexPath:(NSIndexPath *)indexPath 
                     animated:(BOOL)animated 
               scrollPosition:(UICollectionViewScrollPosition)scrollPosition

You can use this method multiple times if you want multiple selections.

Answer 3

didSelectItemAt is not called if you call selectItem programmatically. You should call the method manually after it.

self.collectionView.selectItem(at: IndexPath(item: 0, section: 0), animated: true, scrollPosition: .bottom)
self.collectionView(self.collectionView, didSelectItemAt: IndexPath(item: 0, section: 0))

Answer 4

For right behaviour call 4 function in a row:

// Deselect
self.collection.deselectItem(at: previousPath, animated: true)
self.collectionView(self.collection, didDeselectItemAt: previousPath)

// Select
self.collection.selectItem(at: path, animated: true, scrollPosition: .centeredVertically)
self.collectionView(self.collection, didSelectItemAt: path)