Custom UITableViewCell with UIButton: which button has been clicked?

Question

I'm developing an iOS 4 application with latest SDK and XCode 4.2.

I have a UITableView with sections and with custom UITableViewCell. Every cell has a UIButton and all of these buttons has the same target for UIControlEventTouchUpInside.

This is my code:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString* cellIdentifier = @"CalendarCell";

    CalendarEventCell* cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];

    if (cell == nil)
    {
        NSArray* topLevelObjects =  [[NSBundle mainBundle] loadNibNamed:@"CalendarEventCell" owner:nil options:nil];

        for(id currentObject in topLevelObjects)
        {
            if ([currentObject isKindOfClass:[CalendarEventCell class]])
            {
                cell = (CalendarEventCell *)currentObject;
                [cell.addToCalendarButton addTarget:self action:@selector(addEventToiCal) forControlEvents:UIControlEventTouchUpInside];
                break;
            }
        }
    }
...
}

When user touch inside that button, how can I know on which section and row was the cell that has been clicked?

Answer 1

Place a tag on the button. For example:

CalendarEventCell* cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];

if (cell == nil)
{
    NSArray* topLevelObjects =  [[NSBundle mainBundle] loadNibNamed:@"CalendarEventCell" owner:nil options:nil];

    for(id currentObject in topLevelObjects)
    {
        if ([currentObject isKindOfClass:[CalendarEventCell class]])
        {
            cell = (CalendarEventCell *)currentObject;
            [cell.addToCalendarButton addTarget:self action:@selector(addEventToiCal) forControlEvents:UIControlEventTouchUpInside];
            break;
        }
    }
}
cell.addToCalendarButton.tag = ((indexPath.section & 0xFFFF) << 16) |
                               (indexPath.row & 0xFFFF);

You will need to change your selector to @selector(addEventToiCal:) and update the method to -(void) addEventToiCal:(UIButton *)sender.

You can then add something like the following to -addEventToiCal:

if (!([sender isKindOfClass:[UIButton class]]))
    return;
NSUInteger section = ((sender.tag >> 16) & 0xFFFF);
NSUInteger row     = (sender.tag & 0xFFFF);
NSLog(@"Button in section %i on row %i was pressed.", section, row);

Answer 2

Set button's target to a method in the cell instead of setting the target to the controller itself, create a delegate protocol for the cell with a method like tappedButton:(UIButton *)button inCell:(UITableViewCell *)cell and set the controller as cell's delegate. In the target method call that delegate method.

Then in controller's delegate method implementation you can find out cell's NSIndexPath by calling UITableView's tableView:indexPathForCell:.