objective-c : Use a array to point to another array

Question

I have two Mutable arrays. "friendsArray" contains a whole list os users and "inviteIndex" contains the indexes (indexPath.row) of some of them (get using uiswitch button into a table list).

The I fill inviteIndex array as:

[inviteIndex addObject:[NSNumber numberWithInteger:indexPath.row]];

In order to have only selected users I do:

  for (int i =0; i< [inviteIndex count]; i++) {

        MyElement  *friend =[friendsArray objectAtIndex:[inviteIndex objectAtIndex:i] ];

        NSLog(@"BUTTON PRESSED %@", friend.friendId);

    }

but app crash with message:

[__NSArrayM objectAtIndex:]: index 400931632 beyond bounds [0 .. 4]'

I trid used
MyElement *friend =[friendsArray objectAtIndex:(NSInteger)[inviteIndex objectAtIndex:i] ]; with same result.

Any help please? Thanks in advance.

Answer 1

[inviteIndex objectAtIndex:i] will return an NSNumber object. You want the NSInteger value within the NSNumber object:

for (int i =0; i< [inviteIndex count]; i++) {

    NSInteger index = [[inviteIndex objectAtIndex:i] integerValue];
    MyElement  *friend =[friendsArray objectAtIndex:index];

    NSLog(@"BUTTON PRESSED %@", friend.friendId);

}

Answer 2

index beyond bounds this error comes when you're trying to access an object from an index which are not exist in array.

In your case, seems that friendArrays count is < (less than the) inviteIndex count.

I think the problem is somewhere in this logic, [inviteIndex addObject:[NSNumber numberWithInteger:indexPath.row]];

Check count of inviteIndex.