Question

I have a TableView loading a custom cell and loading the data from a JSON string on a server.
The JSON string is parsed to an array of 14 IDs (id_array).

If cell==nil, then I’m using [id_array objectAtIndex:indexPath.row] to get an ID and fetch some more info about for that row from a server, and set up the cell’s labels and image.

When running the app, the UITableView is loading the visible rows [0,1,2,3,4] (cell height is 70px).
When scrolling down the TableView, row [5] is loaded and fetching data from the server, but the problem is that beyond that point – the TableView is repeating those 6 rows instead of requesting new data from the server for the new rows…

But it does request new data for row [5], which is not visible (and not loaded) when the app first runs.

Anyone have any idea why is this happening?
Thanks!

EDIT: Here is my cellForRowAtIndexPath method

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

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

        for (id currentObject in topLevelObjects) {
            if ([currentObject isKindOfClass:[UITableViewCell class]]) {
                cell = (CustomCell *)currentObject;

                NSString *appsURL = [NSString stringWithFormat:@"http://myAPI.com?id=%@",[app_ids objectAtIndex:indexPath.row]];
                NSLog(@"row -> %d | id -> %@",indexPath.row,[app_ids objectAtIndex:indexPath.row]);
                NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:appsURL]];
                [cell updateAppInfoForCellWithRequest:request];

                break;
            }
        }
    }

    // Configure the cell...

    return cell;
}

Answer 1

If you are setting data only if cell==nil, then that is your issue. UITable builds a cache of table view cells, only creating a new one if cell is nil. Therefore, you must set your data each time, i.e. outside of the cell==nil block.

The example below shows that process. First, grab a cell from the pool, if there isn’t a free cell, create a new one. Set the cell’s values for the appropriate row.

- (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];
    }

    id someData = [id_array objectAtIndex:indexPath.row]

    cell.textLabel.text = [someData someString];

    return cell;
}