Issue Paging with UITableView - ios

Question

Im trying to create an infinite scroll type thing with Instagram using UITableView and AFNetworking however I get this error when I get to the bottom of the View:
CRASH :
-[__NSCFArray insertObject:atIndex:]: mutating method sent to immutable object
2014-01-05 20:51:41.627 Floadt[1579:70b] STACK TRACE :
(
0 CoreFoundation 0x02b775e4 __exceptionPreprocess + 180
1 libobjc.A.dylib 0x027a38b6 objc_exception_throw + 44
2 CoreFoundation 0x02b773bb +[NSException raise:format:] + 139
3 CoreFoundation 0x02bfe365 -[__NSCFArray insertObject:atIndex:] + 101
4 CoreFoundation 0x02b3b2d0 -[NSMutableArray insertObjects:count:atIndex:] + 208
5 CoreFoundation 0x02b3af69 -[NSMutableArray insertObjectsFromArray:range:atIndex:] + 425
6 CoreFoundation 0x02b3ad15 -[NSMutableArray addObjectsFromArray:] + 661
7 Floadt 0x0003f5ec __42-[StreamViewController nextInstagramPage:]_block_invoke + 284
8 Floadt 0x0001edfb __64-[AFJSONRequestOperation setCompletionBlockWithSuccess:failure:]_block_invoke91 + 43
9 libdispatch.dylib 0x035247f8 _dispatch_call_block_and_release + 15
10 libdispatch.dylib 0x035394b0 _dispatch_client_callout + 14
11 libdispatch.dylib 0x0352775e _dispatch_main_queue_callback_4CF + 340
12 CoreFoundation 0x02bdca5e __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 14
13 CoreFoundation 0x02b1d6bb __CFRunLoopRun + 1963
14 CoreFoundation 0x02b1cac3 CFRunLoopRunSpecific + 467
15 CoreFoundation 0x02b1c8db CFRunLoopRunInMode + 123
16 GraphicsServices 0x0453c9e2 GSEventRunModal + 192
17 GraphicsServices 0x0453c809 GSEventRun + 104
18 UIKit 0x01936d3b UIApplicationMain + 1225
19 Floadt 0x0006646d main + 141
20 libdyld.dylib 0x037cb70d start + 1
21 ??? 0x00000001 0x0 + 1
)
Here is how I am making my code, what confuses me is the fact that all my Arrays are Mutable but it states that the mutating method was sent to an immutable object:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
if (scrollView.contentOffset.y == roundf(scrollView.contentSize.height-scrollView.frame.size.height)) {
NSDictionary *page = instagramResponse[#"pagination"];
NSString *nextPage = page[#"next_url"];
[[InstagramClient sharedClient] getPath:[NSString stringWithFormat:#"%#",nextPage] parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) {
instagramResponse = [responseObject mutableCopy];
[instagramResponse addEntriesFromDictionary:responseObject];
[instaPics addObjectsFromArray:responseObject[#"data"]];
[self.tableView reloadData];
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(#"Failure: %#", error);
}];
}
}

Answer 1

before addEntriesFromDictionary the copy of Dictionarylike this
NSDictionary *copyOfDic = [[NSDictionary alloc] initWithDictionary: originalDic copyItems: YES];
if (copyOfDic ) {
[destination addEntriesFromDictionary: copyOfDic ];
[copyOfDic release];
}
or
[instaPics addObjectsFromArray:[responseObject[#"data"]mutable copy]];
or
Your #property yourarray is either initialized with an NSArray or declared copy.
because both would be lead to this error/exception message since the backing ivar would point to an (immutable) NSArray.
If you have declared your property to be of NSMutableArray type, use strong as the storage modifier instead of copy.