Hide UICollectionView items in certain layouts - ios

Question

I have a UICollectionView that uses a couple of different layouts depending on user preferences. I want certain cells to show up for some layouts but not for others. How do I accomplish this? Do I actually need to reload the collection view data?

Answer 1

There are two steps to accomplishing this (which also works with UITableView).
Update the data source. If you're using an NSDictionary or NSArray, then you'll need to add or remove the items you want to show/hide.
Call reloadData on the UICollectionView or UITableView. That's pretty much it.
If you want to remove or add with an animation, that's different. There are a couple more methods in the middle that you have to call and make sure that your update sequence is correct. But that is a different question altogether.
EDIT:
As an example of how to use an array
- (void)methodCalledWhenLayoutChanges:(BOOL)includeOptionalString {
if (includeOptionalString) {
[_collectionViewDataSourceArray addObject:_optionalString];
} else {
[_collectionViewDataSourceArray removeObject:_optionalString];
}
[self.collectionView reloadData];
}
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
return 1;
}
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
return _collectionViewDataSourceArray.count;
}
// Never actually setup a collection view like this. This is just an example of how to reference a data source for creating a collection view cell.
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
UICollectionViewCell *cell = [[UICollectionViewCell alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 50.0f, 50.0f)];
UILabel *textLabel = [[UILabel alloc] initWithFrame:cell.bounds];
textLabel.text = [_collectionViewDataSourceArray objectAtIndex:indexPath.row];
[cell addSubview:textLabel];
return cell;
}