Constraints not working when using viewWithTag to get labels inside UITableviewCell

Question

I really can't get my head around why this isn't working properly. I have a TableViewController with dynamic prototypes. I put 4 labels in a prototype named "InfoCell", and gave them constraints. If i run the app with the following cellForRowAtIndexPath:

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    NSString *cellIdentifier = @"InfoCell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];

    return cell;
}

what I get is this. Everything looks fine 'til now

I did this just to check that the labels were being displayed in the right place. The page is supposed to show 2 cells, so everything looks fine.

Now, the problems start when I try to get a reference to the labels in order to change the text. Even without actually changing the text, if my code looks like this:

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    NSString *cellIdentifier = @"InfoCell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];

    UILabel *nameLabel = (UILabel *)[cell viewWithTag:10];
    UILabel *surnameLabel = (UILabel *)[cell viewWithTag:20];
    UILabel *roleLabel = (UILabel *)[cell viewWithTag:30];
    UILabel *spouseNameLabel = (UILabel *)[cell viewWithTag:40];

    [cell addSubview:nameLabel];
    [cell addSubview:surnameLabel];
    [cell addSubview:roleLabel];
    [cell addSubview:spouseNameLabel];

    return cell;
}

I get this. Labels' positions went nuts

I tried, for example, to change the frame of each label programmatically,

nameLabel.frame = CGRectMake(15.0, 50.0, 120.0, 20.0)

but it just doesn't do anything, I suppose because auto-layout is enabled... but I'm too far into the project to disable auto-layout. Plus I've seen the use of viewWithTag as I wrote above working without the need to re-locate the labels programmatically, so it bugs me not to know what's really happening there!

Answer 1

Remember that when you have constraints added on any of the UI object, you can't change the frame of that object by changing its CGRect . In fact, you should change its constraint value. Now the problem in your code is ,

[cell addSubview:nameLabel];
[cell addSubview:surnameLabel];
[cell addSubview:roleLabel];
[cell addSubview:spouseNameLabel];

above 4 lines. When you have added a UILabel in storyboard, why are you adding them again by using addSubview method ? Remove above 4 lines, and to set text on your UILabel , you already have a reference which you are accessing by using their tag values. So your method should looks like as below.

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
  NSString *cellIdentifier = @"InfoCell";
  UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];

  UILabel *nameLabel = (UILabel *)[cell viewWithTag:10];
  UILabel *surnameLabel = (UILabel *)[cell viewWithTag:20];
  UILabel *roleLabel = (UILabel *)[cell viewWithTag:30];
  UILabel *spouseNameLabel = (UILabel *)[cell viewWithTag:40];

  nameLabel.text = @"";
  surnameLabel.text = @"";
  roleLabel.text = @"";
  spouseNameLabel.text = @"";

  return cell;
}