Sorting an Array error?

Question

I'm trying to sort an array, from a previous post I was pointed to an answer in this thread, Sorting an array of doubles or CLLocationDistance values on the iPhone

Based of this my code is as follows:

NSArray *sortedArray = [listArray sortedArrayUsingFunction:intSort context:nil];


NSInteger intSort(id num1, id num2, void *dummy)
{
    int v1 = [[num1 objectForKey:@"waypoint_order"] intValue];
    int v2 = [[num2 objectForKey:@"waypoint_order"] intValue];

    if (v1 < v2)
        return NSOrderedAscending;
    else if (v1 > v2)
        return NSOrderedDescending;
    else
        return NSOrderedSame;
}

But its crashing on line int v1 = [[num1 objectForKey:@"waypoint_order"] intValue]; with 'objc_exception_throw'.

What am I doing wrong, I must be leaving out some functionality.

Regards, Stephen

Answer 1

1. check num1 dictionary. is it autorelease or u release it somewhere in program.

2. or check value return by Dictionary may be it returning nil;

3. see linkArray object .at the time of creating u assigned last Value to nil or not . eg:[[NSArray alloc]initWithObject:object1,object2,object3,nil];

Answer 2

If these are NSManagedObjects, you want valueForKey:, not objectForKey:

Like this...

int v1 = [[num1 valueForKey:@"waypoint_order"] intValue];

Hope that helps.