✔ Checkmark selected row in UITableViewCell

Do not use [tableview reloadData]; // its a hammer.

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath   *)indexPath
{
    [tableView cellForRowAtIndexPath:indexPath].accessoryType = UITableViewCellAccessoryCheckmark;
}

-(void)tableView:(UITableView *)tableView didDeselectRowAtIndexPath:(NSIndexPath *)indexPath 
{
    [tableView cellForRowAtIndexPath:indexPath].accessoryType = UITableViewCellAccessoryNone;
}

To set a checkmark:

UITableViewCell *cell = ...;
cell.accessoryType = UITableViewCellAccessoryCheckmark;

To select/deselect a cell:

[cell setSelected:TRUE animated:TRUE]; // select
[cell setSelected:FALSE animated:TRUE]; // deselect

To deselect the previous cell use a NSIndexPath *lastSelected ivar to track the last selected cell:

- (void)tableView:(UITableView*)tableView didSelectRowAtIndexPath:(NSIndexPath*)indexPath
{
   if (self.lastSelected==indexPath) return; // nothing to do

   // deselect old
   UITableViewCell *old = [self.tableView cellForRowAtIndexPath:self.lastSelected];
   old.accessoryType = UITableViewCellAccessoryNone;
   [old setSelected:FALSE animated:TRUE];

   // select new
   UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:indexPath];
   cell.accessoryType = UITableViewCellAccessoryCheckmark;
   [cell setSelected:TRUE animated:TRUE];

   // keep track of the last selected cell
   self.lastSelected = indexPath;
}

I found that reloading the data interrupts the deselect animation in an ugly way.

This Swift implementation cleanly adds/removes checkmarks and deselects the row:

func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    if self.lastSelection != nil {
        self.myTableView.cellForRowAtIndexPath(self.lastSelection)?.accessoryType = .None
    }

    self.myTableView.cellForRowAtIndexPath(indexPath)?.accessoryType = .Checkmark

    self.lastSelection = indexPath

    self.myTableView.deselectRowAtIndexPath(indexPath, animated: true)
}

where lastSelection is declared as var lastSelection: NSIndexPath!

No extra activity in cellForRowAtIndexPath needed. Shouldn't be hard to replicate in Obj-C.

In your UITableViewDatasource method:

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

    if(cell == nil )
    {
        cell =[[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];
    }
    if ([indexPath compare:self.lastIndexPath] == NSOrderedSame) 
    {
        cell.accessoryType = UITableViewCellAccessoryCheckmark;
    } 
    else 
    {
        cell.accessoryType = UITableViewCellAccessoryNone;
    }
    return cell;
}

// UITableView Delegate Method
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    self.lastIndexPath = indexPath;

    [tableView reloadData];
}

And lastIndexPath is a property(strong) NSIndexPath* lastIndexPath;