Question

I have a UITableView populated by a SQLite database. I added Section-based Grouping using the sectionIndexTitlesForTableView delegate method today and now when a Cell is selected, the String for indexPath.row is not the same as the text in the selected Cell.

My Code works like this.

1. I create an Array that holds the businesses from the SQLite database.
2. I sort that Array alphabetically.
3. I create an Array of letters of the Alphabet using only the letters of the Alphabet that businesses in the database begin with.
4. I use that Array, along with an NSPredicate to provide Grouped Header views which group the businesses by their first letter, alphabetically.
5. The Selected Row is written to the NSUserDefaults file, and a View Controller is pushed (iPhone), or an Observer is added for that key (iPad).

Unfortunately, since adding the header views, indexPath.row now returns a completely different string to that of the TextLabel of the selected Cell, and so a different Business’ information is displayed.

Here are the important blocks of code for the main arrays.

- (void)viewDidLoad
{
 // Lots of code...
 arrayName = [[NSMutableArray alloc] init];
 NameSet = [[NSMutableSet alloc] init];
 sortedArray = [arrayName sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)];

 alphabet = [[NSMutableArray alloc] init];
 [alphabet addObject:@"{search}"];
 for (int i=0; i<[sortedArray count]-1; i++)
 {
  char alphabetUni = [[sortedArray objectAtIndex:i] characterAtIndex:0];
  NSString *uniChar = [NSString stringwithFormat:@"%c", alphabetUni];
  if (![alphabet containsObject:uniChar])
  {
    [alphabet addObject:uniChar];
  }
 }
 }

 - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
 {
  return [alphabet count];
 }

 - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
 {
 NSInteger rows = 0;

 NSString *alpha = [alphabet objectAtIndex:section];

 NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF beginswith[c] %@", alpha];
 businesses = [sortedArray filteredArrayUsingPredicate:predicate];

 if ([tableView isEqual:self.searchDisplayController.searchResultsTableView]){
    rows = [self.searchResults count];
 }
 else {
    rows = [businesses count];
 }

  return rows;
 }

 - (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection (NSInteger)section
 {
  return [alphabet objectAtIndex:section];
 }

 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
 {
  NSString *CellIdentifier = @"Cell";
  cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
  if (cell == nil) {
    cell = [[UITableViewCell alloc]
             initWithStyle:UITableViewCellStyleDefault
             reuseIdentifier:CellIdentifier];

    cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
  }

  NSString *alpha = [alphabet objectAtIndex:indexPath.section];
  NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF beginswith[c] %@", alpha];
  businesses = [sortedArray filteredArrayUsingPredicate:predicate];

  if ([tableView isEqual:self.searchDisplayController.searchResultsTableView]){
    cell.textLabel.text =
    [self.searchResults objectAtIndex:indexPath.row];
  }
  else{
        NSString *cellValue = [businesses objectAtIndex:indexPath.row];
        cell.textLabel.text = cellValue;
  }
  return cell;

  }

  - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
 {
 NSString *selected = nil;

 if (tableView == self.tableView)
 {
    selected = [businesses objectAtIndex:indexPath.row];
 }
 else if (tableView == searchDis.searchResultsTableView)
 {
    selected = [filteredData objectAtIndex:indexPath.row];
 }

 [def setObject:selected forKey:@"NameChoiceDetail"];

 if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone)
 {
    [self performSegueWithIdentifier:@"NameDetailPush" sender:self];

 }
 }

// Please excuse my horribly written code. I’ve only been working with Objective-C for 4 months, and Programming for about 8 months. Any suggestions/optimisations will be duly noted.

Answer 1

Your table view uses sections but your implementation of tableView:didSelectRowAtIndexPath: doesn’t evaluate the section of the index path. So the code is missing something.

Furthermore, I find that your use of the businesses variable (it’s probably an instance variable) very strange. It is assigned a value in tableView:cellForRowAtIndexPath: but not in tableView:didSelectRowAtIndexPath: even though it is used there. So the outcome if the latter depends on what table cell was displayed last and as a consequence it depends on scrolling user interaction. That might be the reason why the outcome looks rather random.