Question

In my iPhone app I have a table view where I add a tick image to a cell if that objects ‘isConfirmed’ value is true. When entering the detailed view I can edit the confirmed value, and upon popping back to the main table view I need to see the update and not only when I view the main table from a fresh.

So I am using this code in my tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath method`:

UIImageView *tickImg = nil;

    //If confirmed add tick to visually display this to the user
    if ([foodInfo.isConfirmed boolValue])
    {
        tickImg = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"ConfirmedTick.png"]];
        [tickImg setFrame:CGRectMake(0, 0, 32, 44)];
        [cell addSubview:tickImg];
    }
    else 
    {
        [tickImg removeFromSuperview];
    }

What this does it successfully add the tick image to my cells which have a true value for isConfirmed and when going into the detail view of an object and setting it to TRUE and retuning, the tick appears, however I can’t get it to work the other, so if the tick is there and I go into the detail view to unconfirmed it, the tick doesn’t disappear.

Answer 1

Are you calling [self.tableView reloadData]; on the VC’s viewWillAppear:?

Also, the approach you’re using to configure the cell is error-prone. Since the tableView is reusing the cells, you can’t be sure what state a cell is in when you dequeue it.

A better approach would be to build the cells consistently:

static NSString *CellIdentifier = @"MyCell";
UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];

    // always create a tick mark
    UIImageView *tickImg = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"ConfirmedTick.png"]];
    tickImg.tag = kTICK_IMAGE_TAG;
    tickImg.frame = CGRectMake(0, 0, 32, 44);
    [cell addSubview:tickImg];
}

// always find it
UIImageView *tickImg = (UIImageView *)[cell viewWithTag:kTICK_IMAGE_TAG];

// always show or hide it based on your model
tickImg.alpha = ([foodInfo.isConfirmed boolValue])? 1.0 : 0.0;

// now your cell is in a consistent state, fully initialized no matter what cell
// state you started with and what bool state you have