Question

I have a table view with 3 items, one of which I have behind a button. When the button is selected, I want to hide that button, revealing the item behind it. I am displaying the table row using a table view cell. When I select the one button to hide, scrolling through the table hides more buttons. The hiding of the button seems to hide a button based on some location within the viewable rows of the current view. I’m trying to hide the button on a specific row.

I can write to the NSLog whenever I hit the code to hide a button and I will only get there once, but as I scroll through the table, the hidden attribute for the button applies to other rows that come into view. If I select the button on row 53 I want only the button in row 53 hidden, not buttons on other rows in the 120 row table.

Has anyone ever done what I am trying to do? Any help I can get to figure out what is happening would be appreciated. Thanks.

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *ElementCellIdentifier = @"ElementCellIdentifier";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:ElementCellIdentifier];
    if (cell == nil) {
        NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"ElementRowCell"
                                                 owner:self options:nil];
        if ([nib count] > 0) {
            cell = self.tvCell;
        } else {
            NSLog(@"failed to load ElementRowCell nib file!");
        }
    }

    NSUInteger row = [indexPath row];

    UILabel *atomic_number = (UILabel *)[cell.contentView viewWithTag:1];                               
    atomic_number.text = [NSString stringWithFormat:@"%d",elements_table[row].atomic_number];

    UILabel *element_name = (UILabel *)[cell.contentView viewWithTag:2];
    element_name.text = [NSString stringWithCString:elements_table[row].element_name];

    UILabel *element_symbol = (UILabel *)[cell.contentView viewWithTag:3];
    element_symbol.text = [NSString stringWithCString:elements_table[row].element_symbol];

    return cell;
}

- (IBAction)buttonPressed:(id)sender {

NSLog(@"Getting to buttonPressed from row button");
UIButton *pressedButton = (UIButton *)sender;
NSIndexPath *indexPath = [self.mainTableView indexPathForCell:     (UITableViewCell *)[sender superview]];
pressedButton.hidden = TRUE;

}

Answer 1

Sorry.
Basically what’s happening is you are hiding the instance of the button in that specific table view cell. The problem is when it gets dequeue’d for another row nothing is restoring it’s state. And if you were to just restore it’s state to visible then the rows you clicked would be forgotten. You will need to save the rows that have been clicked already to be able to properly restore state in tableView:cellForRowAtIndexPath:.

How I would handle this is declare an NSMutableSet *selectedIndexPaths;. And use this to store the rows I have selected. Then when the button is clicked add that indexPath to the set like so.

- (IBAction)buttonPressed:(UIButton *)button{
    if (![button isKindOfClass:[UIButton class]]) return;
    UIView *finder = button.superview;
    while ((![finder isKindOfClass:[UITableViewCell class]]) && finder != nil) {
        finder = finder.superview;
    }
    if (finder == nil) return;
    UITableViewCell *myCell = (UITableViewCell *)finder;
    NSIndexPath *indexPath = [self.mainTableView indexPathForCell:myCell];
    [selectedIndexPaths addObject:indexPath];
    button.hidden = TRUE;
    NSLog(@"IndexPathRow %d",indexPath.row);
}

Now to properly restore state when scrolling in tableView:cellForRowAtIndexPath: use an if statement to set the button’s hidden property, like so:

buttonPropertyName.hidden = ([selectedIndexPaths containsObject:indexPath]);