table view cell deleting now working

Question

ive used the sdk standard code for deleting however it crashes once i press the delete button. i am using this code

 - (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {

 if (editingStyle == UITableViewCellEditingStyleDelete) {
 // Delete the row from the data source
 [tableView deleteRowsAtIndexPaths:[tableFavoritesData arrayWithObject:indexPath] withRowAnimation:YES];
 }   

 }

i tried with both NSMutableArray instead of tableFavoritesData however nothing works. can anyone help me out?

Answer 1

Well, basically what you want to do is:

1. Delete the row from the data source (array).
2. Tell the table view that you have deleted a row from the data source.

Correct code should probably look like that:

if (editingStyle == UITableViewCellEditingStyleDelete) {
 [tableFavoritesData removeObjectAtIndex:indexPath.row];
 [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
 }   

EDIT: I didn't notice another error.

You need to specify the type of animation, not just pass YES or NO. For example: UITableViewRowAnimationFade. Check out possible UITableViewRowAnimation values here.

EDIT 2: For the comment below (comment formatting suck): Check out NSNotificationCenter in the docs, especially addObserver:selector:name:object: and postNotificationName:object: methods.

In your other view controller (probably viewDidLoad method):

[[NSNotificationServer defaultCenter] addObserver:self selector:@selector(deletedRow:) name:@"RowDeleted" object:nil];

-(void) deletedRow:(NSNotification*) notification
{
  NSDictionary* userInfo = [notification userInfo];
  NSIndexPath indexPath = [userInfo objectForKey:@"IndexPath"];
 // your code here
}

and while deleting the row:

if (editingStyle == UITableViewCellEditingStyleDelete) {
...
[[NSNotificationServer defaultCenter] postNotificationName:@"RowDeleted" object:self userInfo:[NSDictionary dictionaryWithObject:indexPath forKey:@"IndexPath"]];
     }   

Just remember that you need to remove observer from notification center when you dealloc the other UIViewController:

[[NSNotificationServer defaultCenter] removeObserver: self];

Hope I didn't make much errors, I don't have access to XCode atm.

Answer 2

If you looked at the console, it will most probably tell you that your model (your data structure) doesn't match what the table expects. I.e. your delegate method

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section

must return one less than before.

Also, [tableFavoritesData arrayWithObject:indexPath] looks very strange and is probably not what's expected. Maybe you want [NSArray arrayWithObject:indexPath] here. And remove the data from your model first.