CODEWITHSUNDEEP
iosuitableviewuilabel
David Bridge
David Bridge

Reputation: 33

iOS xcode, adding UILabel subview to custom table cell, label text does not update on screen

I've created a custom UITableViewCell class, and used the layoutSubviews method to add a custom label. Like this:

- (void)layoutSubviews
{
    [super layoutSubviews];

    if (statusLabel == nil)
    {
        statusLabel = [[UILabel alloc]initWithFrame:CGRectMake(430.0, 10.0, 100.0, 20.0)];
        [statusLabel setTextAlignment:UITextAlignmentRight];
        [statusLabel setText:@"Status, set in code"];
        statusLabel.tag = 1;

        [self.contentView addSubview:statusLabel];
    }        
}

As you can see, I have set the initial text of the label to "Status, set in code".

In the table view controller I set the text for this custom label in the cellForRowAtIndexPath method, like so:

- (UITableViewCell *)tableView:(UITableView *)tableView
     cellForRowAtIndexPath:(NSIndexPath *)indexPath 
{
    int index = [indexPath row];

    NSString *introducerString =[introducers objectAtIndex:index];
        NSArray *parts = [introducerString componentsSeparatedByString:@","];

    static NSString *MyIdentifier = @"Requester";
    UITableViewCell *cell = [tableView
                             dequeueReusableCellWithIdentifier:MyIdentifier];
    if (cell == nil) 
    {
        cell = [[[DanceCardCell alloc] initWithStyle:UITableViewCellStyleSubtitle
                                       reuseIdentifier:MyIdentifier] autorelease];
    }

    UIImage *image = [UIImage imageNamed:@"1.jpg"];
    [cell.imageView setImage:image];
    cell.textLabel.text = [parts objectAtIndex:1];
    cell.detailTextLabel.text = @"Some text";

    UILabel *statusLabel = (UILabel *)[cell viewWithTag:1];
    statusLabel.text = @"Did it!";

    return cell;
}

I'm using one table view to display two lists, depending on which of two buttons is pressed. When a button is pressed the appropriate table view controller is attached to the table view, and the reloadData method is called to trigger display of the new data. The new data does display, but the custom label text, which should read "Did it!" reads "Status, set in code ...", until I switch lists again twice.

How can I get the new text for the custom label to update straight away? I have checked the official documentation and cannot find any reference to refreshing a cell's display after updating its custom content.

Here is a screen shot to demonstrate what happens: http://www.dsbsystems.co.uk/images/xcode1.png

Upvotes: 0

Views: 5693

Answers (1)

Jesper
Jesper

Reputation: 7605

You're initializing the cell and immediately attempting to find the statusLabel with tag 1 inside it. layoutSubviews hasn't had the opportunity to be called yet, and so the label hasn't been created and added. (I suggest overriding the designated initializer method on your table view cell and creating the label there.)

Because of this, when you try to pull out statusLabel, it becomes nil because there's no such view, and messaging (calling a method on) nil simply does nothing (actually, it returns nil). You will need to watch out for this going forward if you're used to things blowing up with e.g. null reference exceptions.

When the cell is requested again, a new cell isn't needed because it's available from the reuse queue, and the label will be found correctly.

Upvotes: 2

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