Question

In my application I have the array, which create in Main_View_Controller from json response in loop:
Main_View_Controller.m

NSMutableArray *Cities = [[NSMutableArray alloc] init];
while (ItemsFromParsedResponse = (NSDictionary *)[enumerator nextObject]) {
        AppDelegate *dataCenter = (AppDelegate*)[[UIApplication sharedApplication] delegate];
        dataCenter.CityLabel = [ItemsFromParsedResponse objectForKey:@"label"];
        [Cities addObject:dataCenter.CityLabel];
        dataCenter = nil;
    }
AppDelegate *dataCenter = (AppDelegate*)[[UIApplication sharedApplication] delegate];
dataCenter.CityInfo = Cities;

This array must be presented in Popover, containing TableView. I’ve trying to delegate array to popover same like delegate it to AppDelegate, but it’s not work. If I read dataCenter.CityInfo in my CityList_Popover_Contoller, it has nil value.

CityList_Popover_Controller.m

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath     *)indexPath
{//some standard code

AppDelegate *dataCenter = (AppDelegate*)[[UIApplication sharedApplication] delegate];
cell.textLabel.text = [dataCenter.CityInfo objectAtIndex:indexPath.row];
[tableView reloadData];
return cell;
}

How can I load CityInfo only if it is not-nil? And how can I tracking changes in this array and dynamically update table content according new data in array?

Sorry if my question too simple, but I spent a lot of time to make it work.

Thanks for any advice!

Answer 1

Just a simple if-check should work:

AppDelegate *dataCenter = appDelegate;
if ([dataCenter.CityInfo objectAtIndex:indexPath.row])
{
     cell.textLabel.text = [dataCenter.CityInfo objectAtIndex:indexPath.row];
}
else 
{
     NSLog(@"Whoops, null data at row %i", indexPath.row);
}
// NEVER call reload data here, you are 
// already reloading data when this 
// method is called, will end up in corruption.
// [tableView reloadData];
return cell;