Problem with releasing of object - iphone

Question

I have navigation application with 3 levels of hierarchy. My first level is tabel view controller. The nib file of this controller is "TableView". I have problem here. My code is this:
RootViewController
#import "RootViewController.h"
#import "SubCategory.h"
#import "OffersViewController.h"
#implementation RootViewController
#synthesize subCategories;
#synthesize offersView;
- (void)dealloc
{
NSLog(#"root dealloc");
//[subCategories release];
[super dealloc];
}
- (void)viewDidLoad
{
NSLog(#"root view load");
[super viewDidLoad];
self.title = #"Sub Categories";
NSString *jsonArray = [NSString stringWithFormat:#"{ "
#" \"sub-categories\": { "
#" \"parent\": \"1\", "
#" \"count\": \"2\", "
#" \"sub-category\": [{ "
#" \"id\": \"1\", "
#" \"name\": \"Buy\" "
#" }, "
#" { "
#" \"id\": \"2\", "
#" \"name\": \"Sell\" "
#" }] "
#" } "
#" }"];
SubCategory* categories = [[SubCategory alloc] init];
subCategories = categories;
[subCategories parseJSON:jsonArray];
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
NSLog(#"root sections");
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
NSLog(#"root numberOfRows");
return [subCategories.subCategoryName count];
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"root didSelectRow");
OffersViewController * offers = [[OffersViewController alloc] initWithNibName:#"OffersView" bundle:nil];
offersView = offers;
// I have exception on this row. exception is:
//-[__NSArrayI objectAtIndex:]: message sent to deallocated instance 0x4b04c00
offersView.title = [NSString stringWithFormat:#"%#", [subCategories.subCategoryName objectAtIndex:indexPath.row]];
[self.navigationController pushViewController:offersView animated:YES];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"root cellForRow");
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"cachedCell"];
if (cell == nil) {
cell = [[[UITableViewCell alloc] init] autorelease];
}
cell.textLabel.text = [subCategories.subCategoryName objectAtIndex:indexPath.row];
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
return cell;
}
#end
SubCategory
#import "SubCategory.h"
#import "JSON.h"
#implementation SubCategory
#synthesize parentId;
#synthesize count;
#synthesize subCategoryId;
#synthesize subCategoryName;
- (void) parseJSON: (NSString*) jsonArray {
NSDictionary *results = [jsonArray JSONValue];
NSString *parent = (NSString*) [[results objectForKey:#"sub-categories"] objectForKey:#"parent"];
parentId = [parent intValue];
NSString *cnt = (NSString*) [[results objectForKey:#"sub-categories"] objectForKey:#"count"];
self.count = [cnt intValue];
NSDictionary *subCategories = [[results objectForKey:#"sub-categories"] objectForKey:#"sub-category"];
NSMutableArray *namesArray = [[NSMutableArray alloc] initWithCapacity:[subCategories count]];
NSMutableArray* idArray = [[NSMutableArray alloc] initWithCapacity:[subCategories count]];
for (NSDictionary *subCategory in subCategories) {
[idArray addObject:[subCategory objectForKey:#"id"]];
[namesArray addObject:[subCategory objectForKey:#"name"]];
}
subCategoryId = [NSArray arrayWithArray:idArray];
subCategoryName = [NSArray arrayWithArray:namesArray];
[idArray release];
[namesArray release];
//[parent release];
//[cnt release];
}
#end
I don't know why my object is released. Can someone help me.
EDIT: Added SubCategory code

Answer 1

Here's the problem:
NSMutableArray *namesArray = [[NSMutableArray alloc] initWithCapacity:[subCategories count]];
NSMutableArray* idArray = [[NSMutableArray alloc] initWithCapacity:[subCategories count]];
...
subCategoryId = [NSArray arrayWithArray:idArray];
subCategoryName = [NSArray arrayWithArray:namesArray];
[idArray release];
[namesArray release];
At this point, subCategoryId and subCategoryName are autoreleased. This means they won't be accessible after the parseJSON: method finishes. You have two options:
// Because idArray and namesArray are already retained (you alloc'd them)
subCategoryId = idArray;
subCategoryName = namesArray;
or:
...
// this is equivalent to what you have now, except these two will be retained.
// this is different from the above because subCategoryId and subCategoryName are now NSArrays, whereas above they were NSMutableArrays.
subCategoryId = [idArray copy];
subCategoryName = [namesArray copy];
...

Answer 2

The scope of SubCategory categories is only your viewDidLoad. When you make a shallow copy, it/or the copy will not be available outside your scope, you need to retain it when assigning it to subCategories like
subCategories = [categories retain];
Also, you can forego using the SubCategory categories at all. Instead do:
subCategories = [[SubCategory alloc] init];
[subCategories parseJSON:jsonArray]; }