Question

I’m developing a GIS-based application and I have organized data fro the user to search in different categories. I have arranged them in a plain UITableView.Now, every category has a correspondent ID string (f.e.: category Hospitals has an ID : f556682-de5tgh4dde-ff478).I have made two arrays: One that holds the categories and one that holds the ID strings.I think the association of the ID string to each category must be done via a NSMutableDictionary, but not sure how to do it and how to make a string that is created dynamically each time the user selects a determinate number of rows and is the result of the concatenation of the ID strings of the selected cells? I need this string to be passed to a server that depending of the string creates on the fly KML files.(The reason I need it.)This is the code I have done until now:

  NSDictionary *dictionary = [gisCategoryID objectAtIndex:indexPath.row];//gisCategoryID is an array that holds the ID strings
  NSLog(@"ID %@", [dictionary objectForKey: @"ID");
  NSLog(@"Name %@", [dictionary objectForKey: @"Name");

  NSMutableString *categString = [[[NSMutableString alloc] init] autorelease];
  for (NSMutableDictionary *categInfo in dictionary)
      [categString appendFormat: @"%@&", [categInfo objectForKey:@"ID"]];

I have doubts for this being the correct way because every time I select a row, the app crashes.

Answer 1

// create a new mutable dictionary from two NSArrays which hold NSStrings: iDArray and categoryArray

// these arrays already exist and contain NSStrings and have the same number of items.

NSMutableDictionary * myDictionary = [[NSMutableDictionary alloc] initWithCapacity:25];
int i = 0;
for (i = 0; i < [iDArray count]; i++) {
[myDictionary addObject:[categoryArray objectAtIndex:i] forKey:[iDArray objectAtIndex:i]];
}