UITableView tap to deselect cell

Here is an even cleaner solution:

- (NSIndexPath *)tableView:(UITableView *)tableView willSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    if ([[tableView indexPathForSelectedRow] isEqual:indexPath]) {
        [tableView deselectRowAtIndexPath:indexPath animated:YES];
        return nil;
    }
    return indexPath;
}

You can actually do this using the delegate method willSelectRowAtIndexPath:

- (NSIndexPath *)tableView:(UITableView *)tableView willSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
    if ([cell isSelected]) {
        // Deselect manually.
        [tableView.delegate tableView:tableView willDeselectRowAtIndexPath:indexPath];
        [tableView deselectRowAtIndexPath:indexPath animated:YES];
        [tableView.delegate tableView:tableView didDeselectRowAtIndexPath:indexPath];

        return nil;
    }

    return indexPath;
}

Note that deselectRowAtIndexPath: won't call the delegate methods automatically, so you need to make those calls manually.

When using "Multiple Selection" mode, "didSelectRowAtIndexPath" will not be called when you click a row that is already selected. More than one row can still be selected programatically in "Single Selection" mode and the rows will trigger didSelectRowAtIndexPath on all clicks.

Just a heads up to anyone who was having the same problems.

in Swift 4:

func tableView(_ tableView: UITableView, willSelectRowAt indexPath: IndexPath) -> IndexPath? {

    if let indexPathForSelectedRow = tableView.indexPathForSelectedRow,
        indexPathForSelectedRow == indexPath {
        tableView.deselectRow(at: indexPath, animated: false)
        return nil
    }
    return indexPath
}