UITableViewCellAccessoryCheckmark - one checkmark at the time

Matic · July 2009

Hello,

how can I change the following code (or write new code ) to allow only one checkmark at the time in all sections (there are many sections).

- (void)tableView:(UITableView *)tableView 
didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
	UITableViewCell *newCell =[tableView cellForRowAtIndexPath:indexPath];
	int newRow = [indexPath row];
	int oldRow = [lastIndexPath row];
	
	if (newRow != oldRow)
		{
			newCell = [tableView  cellForRowAtIndexPath:indexPath];
			newCell.accessoryType = UITableViewCellAccessoryCheckmark;
			
			UITableViewCell *oldCell = [tableView cellForRowAtIndexPath: lastIndexPath]; 
			oldCell.accessoryType = UITableViewCellAccessoryNone;
			
			lastIndexPath = indexPath;	
		}
	
	BusInfoAppDelegate *appDelegate =  
    (BusInfoAppDelegate *)[[UIApplication sharedApplication] delegate];  
    Station *arrivalStationPicked = [[sectionArray
									  objectAtIndex:indexPath.section] objectAtIndex:indexPath.row];
	appDelegate.arrivalStationPicked =arrivalStationPicked;
	
	
	[tableView deselectRowAtIndexPath:indexPath animated:YES];
	
}

BrianSlick · July 2009

What I do is have a property called "selection" in the view controller. In the case of allowing only a single selection, that property just needs to be of the type of your data model that you are listing. In my case, I'm typically using an NSString, but looks like you might want to use a 'Station' property.

Then I do something like this in cellForRowAtIndexPath:. In my case I'm putting a custom checked image on the left, but you can do the same thing with your checkmark accessory.

if ([self selection] != nil)
{
   if ([[self selection] localizedCaseInsensitiveCompare:currentModelString] == NSOrderedSame)
   {
      [[cell imageView] setImage:[UIImage imageNamed:kCheckedImage]];
      [[cell textLabel] setTextColor:[UIColor blackColor]];
   }
   else
   {
      [[cell imageView] setImage:[UIImage imageNamed:kUncheckedImage]];
      [[cell textLabel] setTextColor:[UIColor grayColor]]; 
   }
}
else
{
   [[cell imageView] setImage:[UIImage imageNamed:kUncheckedImage]];
   [[cell textLabel] setTextColor:[UIColor grayColor]]; 
}

If there is a selection, figure out if this current item is the same as that selection, and respond accordingly. If there isn't a selection, show nothing.

Then I do almost the exact same thing in didSelectRowAtIndexPath:

if ([self selection] != nil)
{
   if ([[self selection] localizedCaseInsensitiveCompare:currentModelString] == NSOrderedSame)
   {
      [[cell imageView] setImage:[UIImage imageNamed:kUncheckedImage]];
      [[cell textLabel] setTextColor:[UIColor grayColor]];
      [self setSelection:nil];
   }
   else
   {
      [[cell imageView] setImage:[UIImage imageNamed:kCheckedImage]];
      [[cell textLabel] setTextColor:[UIColor blackColor]];
      [self setSelection:currentModelString];
   }
}
else
{
   [[cell imageView] setImage:[UIImage imageNamed:kCheckedImage]];
   [[cell textLabel] setTextColor:[UIColor blackColor]];
   [self setSelection:currentModelString]; 
}

//...

[tableView reloadData];

Same basic idea. If the item is already selected, turn it off, if not turn it on, etc. Then the reload will take care of resetting the checked status of other items.

If you want to allow multiple selections, then do the same basic thing, but make your 'selection' property be an array. As items are de/selected, add/remove them to/from the array, then in cellForRow react depending on if your current object is in the selection array.

Matic · July 2009

It is working perfectly now! Thanks! :)

kareem_zok · July 2009

BrianSlick;107145 said:
What I do is have a property called "selection" in the view controller. In the case of allowing only a single selection, that property just needs to be of the type of your data model that you are listing. In my case, I'm typically using an NSString, but looks like you might want to use a 'Station' property.

Then I do something like this in cellForRowAtIndexPath:. In my case I'm putting a custom checked image on the left, but you can do the same thing with your checkmark accessory.
if ([self selection] != nil)
{
   if ([[self selection] localizedCaseInsensitiveCompare:currentModelString] == NSOrderedSame)
   {
      [[cell imageView] setImage:[UIImage imageNamed:kCheckedImage]];
      [[cell textLabel] setTextColor:[UIColor blackColor]];
   }
   else
   {
      [[cell imageView] setImage:[UIImage imageNamed:kUncheckedImage]];
      [[cell textLabel] setTextColor:[UIColor grayColor]]; 
   }
}
else
{
   [[cell imageView] setImage:[UIImage imageNamed:kUncheckedImage]];
   [[cell textLabel] setTextColor:[UIColor grayColor]]; 
}
If there is a selection, figure out if this current item is the same as that selection, and respond accordingly. If there isn't a selection, show nothing.

Then I do almost the exact same thing in didSelectRowAtIndexPath:
if ([self selection] != nil)
{
   if ([[self selection] localizedCaseInsensitiveCompare:currentModelString] == NSOrderedSame)
   {
      [[cell imageView] setImage:[UIImage imageNamed:kUncheckedImage]];
      [[cell textLabel] setTextColor:[UIColor grayColor]];
      [self setSelection:nil];
   }
   else
   {
      [[cell imageView] setImage:[UIImage imageNamed:kCheckedImage]];
      [[cell textLabel] setTextColor:[UIColor blackColor]];
      [self setSelection:currentModelString];
   }
}
else
{
   [[cell imageView] setImage:[UIImage imageNamed:kCheckedImage]];
   [[cell textLabel] setTextColor:[UIColor blackColor]];
   [self setSelection:currentModelString]; 
}

//...

[tableView reloadData];
Same basic idea. If the item is already selected, turn it off, if not turn it on, etc. Then the reload will take care of resetting the checked status of other items.

If you want to allow multiple selections, then do the same basic thing, but make your 'selection' property be an array. As items are de/selected, add/remove them to/from the array, then in cellForRow react depending on if your current object is in the selection array.

how can we make it many selection at a time ???

BrianSlick · July 2009

BrianSlick;107145 said:
If you want to allow multiple selections, then do the same basic thing, but make your 'selection' property be an array. As items are de/selected, add/remove them to/from the array, then in cellForRow react depending on if your current object is in the selection array.

kareem_zok;108218 said:
how can we make it many selection at a time ???

Try reading the whole post next time.

kareem_zok · July 2009

BrianSlick;108306 said:
Try reading the whole post next time.

ahh lol ok i didnt notice it before tanks :D:D but what [self selection] do in your code coz mine is almost same but it doesn't check always all items

Nathan187 · February 2010

kareem_zok;108619 said:
ahh lol ok i didnt notice it before tanks :D:D but what [self selection] do in your code coz mine is almost same but it doesn't check always all items

I tried getting this work but it's not quite there. The problem I have is, when I select an item....it doesn't display the checkmark accessory item initially. But when you scroll a lot of items and return to what you selected, then the item is checked. Some how the reload data seems to be messing it up somehow.

I've tried following Brian's example but I'm think it works in that case since it appears to be a custom cell. This thing has been quite frustrating.

thanks

Nathan187 · February 2010

Nathan187;170976 said:
I tried getting this work but it's not quite there. The problem I have is, when I select an item....it doesn't display the checkmark accessory item initially. But when you scroll a lot of items and return to what you selected, then the item is checked. Some how the reload data seems to be messing it up somehow.

I've tried following Brian's example but I'm think it works in that case since it appears to be a custom cell. This thing has been quite frustrating.

thanks

Update: I can only get this code to work if my cell is a custom cell. I tried using just a table view with normal/regular cells but the reload event/action always would wipe out the disclosure check. I'm not sure if earlier postings suggested that this code works best for custom table view cells. I'm glad I finally got passed this. It was really pissing me off for a while.

Thanks for posting the working code.

BrianSlick · February 2010

It's a logic issue, not a cell issue. If you were unable to make it work with standard cells, you were doing something wrong.

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