Question: I'm trying to set the properties of an object, but it remains null. Can anyone tell me why, please?

Declaration:

```
@property (nonatomic, strong) ListItem *listItem

```

Here's the code:

```
NSLog(@"Selected: %@", [self.fetchedResultsController objectAtIndexPath:indexPath]);
[listItem setCategory:[self.fetchedResultsController objectAtIndexPath:indexPath]];
NSLog(@"set %@", listItem);

```

and the output:

```
2012-06-28 14:47:43.037 MarketList[10508:fb03] Selected: <Category: 0xb72a9e0> (entity: Category; id: 0xb7252e0 <x-coredata://F9BFC1DF-1D80-477E-9BC6-3C0949AD922F/Category/p2> ; data: {
listItem = "<relationship fault: 0x6d29930 'listItem'>";
name = "Teste 2";})
2012-06-28 14:47:43.038 MarketList[10508:fb03] set (null)

```

Answer: 
1. there is a semicolon missing in your property declaration (assuming this is just a typo though).
2. Do you ever actually initialize the ListItem? (ie `listItem = [[ListItem alloc] init];`
If you don't, the pointer to it will be nil, and would cause exactly this behavior (calls with a nil pointer are just ignored).
Just alloc the object before using it. Alloc it in viewDidLoad.