Can't update UILabel text in existing cell

Question

This seems like it should be really easy, but I can't get it to work. I've seen a lot of similar posts, and tried the solutions, but none of them have worked for me.

Basically, I'm trying to update the text of a label in a cell. It works the first time I create the cell, but doesn't work subsequently when I get the cell from dequeueReusableCellWithIdentifier . By the way, I'm actually using a DTGridView , which is somewhat similar to a UITableView . Here is the relevant code from my view controller:

- (DTGridViewCell *)gridView:(DTGridView *)gv viewForRow:(NSInteger)rowIndex column:(NSInteger)columnIndex {

    EntityViewCell *cell = [self entityViewCellForGridView:gv];

    // Find the single dimension index of the cell
    NSUInteger index = [self indexOfGridView:gv row:rowIndex column:columnIndex];

    [self configureCell:cell atIndex:index];

    return cell;
}

- (EntityViewCell *)entityViewCellForGridView:(DTGridView *)gv {
    NSString *CellIdentifier = @"EntityViewCell";

    EntityViewCell *cell = (EntityViewCell *)[gv dequeueReusableCellWithIdentifier:CellIdentifier];

    if (!cell) {
        cell = (EntityViewCell *)[EntityViewCell loadCellWithReuseIdentifier:CellIdentifier];
    }
    return cell;
}

- (void)configureCell:(EntityViewCell *)cell atIndex:(NSInteger)index {
    NSString *name = [[self.data objectAtIndex:index] valueForKey:@"name"];
    if (!name) {
        name = @"";
    }
    cell.title = name;

    // Change the title of the cell if it is selected
    if ([self.selectedCells objectForKey:[NSNumber numberWithInt:index]] != nil) {
        cell.title = @"SELECTED";
    }
}

And here is the relevant code from the EntityViewCell class:

- (void) setTitle: (NSString *) aTitle {
    if (!label) {
        label = [[UILabel alloc] initWithFrame: CGRectZero];
    }
    label.text = aTitle; 
    [self setNeedsLayout];
}

The cell's title is correctly set to the value in my data array, but it never changes to SELECTED after selecting a cell. I have verified through debugging that setTitle is being called with aTitle set to SELECTED when a cell has been touched, so I'm not sure why the view is not showing this.

Thanks!

Answer 1

In the upper code you are changing the property title and in the lower code you are changing the property text. Could this be the problem?

Answer 2

I was able to solve this by adding [self setNeedsDisplay] to the end of the DTDataGrid reloadData function. I'm not sure why this is needed (and adding it to my cell's setTitle doesn't work).

I'm a little worried about the efficiency here, but I don't know of a better way to handle this (I'm pretty new to iOS). Right now, I call reloadData every time a cell is selected, and since I added setNeedsDisplay to the DTDataGrid , it redraws the entire data grid every time. There must be a better way... any ideas?