Ios – How to tell when a UICollectionViewCell disappears

cocoa-touchiosuicollectionviewuicollectionviewcell

I have a collection view where the cells contain UIImageViews, and I'm trying out adding a label as a subview to these views. The problem is that since the cells are reusable, labels keep getting added. I can, of course, check whether my label already exists and reuse it, but I'd really like to clean up after myself. Is there a way to tell when the cell disappears and remove the label then? I've looked at the various docs and don't find any methods that seem promising. Maybe I'm just missing it.

Best Solution

Delegate method: collectionView:didEndDisplayingCell:forItemAtIndexPath:

But you should probably just create a custom cell and reuse instead of creating and destroying...

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Ios – How to disable the UITableView selection

All you have to do is set the selection style on the UITableViewCell instance using either:

Objective-C:

cell.selectionStyle = UITableViewCellSelectionStyleNone;

[cell setSelectionStyle:UITableViewCellSelectionStyleNone];

Swift 2:

cell.selectionStyle = UITableViewCellSelectionStyle.None

Swift 3 and 4.x:

cell.selectionStyle = .none

Further, make sure you either don't implement -tableView:didSelectRowAtIndexPath: in your table view delegate or explicitly exclude the cells you want to have no action if you do implement it.

More info here and here

Ios – Setting custom UITableViewCells height

Your UITableViewDelegate should implement tableView:heightForRowAtIndexPath:

Objective-C

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    return [indexPath row] * 20;
}

Swift 5

func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    return indexPath.row * 20
}

You will probably want to use NSString's sizeWithFont:constrainedToSize:lineBreakMode: method to calculate your row height rather than just performing some silly math on the indexPath :)

Best Solution

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