Question

im new to xcode and i am doing this code to fill up the table view with annotation titles but the function gets called more than once and the table cells are filled with all repeated values , how is the function called in xcode , how can i stop this function from getting called more than once

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

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil) 
    {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
    }
    NSLog(@"this is a test text            ");
    NSMutableArray *annotations = [[NSMutableArray alloc] init];
    int i=0;
    if(indexPath.section == 0)
    {
        for(iCodeBlogAnnotation *annotation in [map annotations])
        {
            i++;
            NSLog(@"this is the no %d",i);
            [annotations addObject:annotation]; 
        }

        cell.textLabel.text = [[annotations objectAtIndex:indexPath.row] title];
    }

    return cell;
}

Any help would be deeply appreciated ,
Thank you for your help in advance

Answer 1

You can’t really control when it’s called. It’s called each time your tableview wants to display a new cell. You use the indexPath to determine what to put in that cell. It’s called at least once per cell that’s on the screen (sometimes more if the table is scrolled up and down).

You don’t need to create the temporary array each time this function is called, just use [map annotations] directly :

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    // There will be one row per annotation
    return [[map annotations] count]
}

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

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil) 
    {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
    }

    // Put the text from this annotation into this cell
    cell.textLabel.text = [[[map annotations] objectAtIndex:indexPath.row] title];

    return cell;
}

I hope I’ve understood your question. If not, please tell me in the comments below!