Question

I have a

NSDictionary* dict = [[NSDictionary alloc]initWithObjectsAndKeys::arrayOne,@"Plants",arrayTwo,@"Animals"),arrayThree,@"Birds",nil];`

self.displayArray =[[dict allKeys] sortedArrayUsingSelector:@selector(compare:)];

Everything works fine, I am able to see all the key value/pair in the table but they are in sorted order. i.e Animals,Birds,Plants.

But I want to display as Plants,Animals,Birds.

Can anyone tell me how to sort the array in my customized order?
I have googled and found that we can use NSSortDescriptor for sorting. But I am not very clear with that. Can anyone help me ?

Answer 1

As your ordering doesnt follow any natural order, a simple solution could be to keep track of the order with another array

NSArray *array1 = [NSArray arrayWithObjects:@"rose",@"orchid",@"sunflower",nil];
NSArray *array2 = [NSArray arrayWithObjects:@"dog", @"cat",@"ogre",@"wookie", nil];
NSArray *array3 = [NSArray arrayWithObjects:@"parrot",@"canary bird",@"tweety",@"bibo",nil];


NSArray *keys = [NSArray arrayWithObjects:@"Plants",@"Animals",@"Birds", nil];

NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:
                                    array1,[keys objectAtIndex:0],
                                    array2,[keys objectAtIndex:1], 
                                    array3,[keys objectAtIndex:2], 
                          nil];

for (NSString *key in keys) {
    NSLog(@"%@ %@", key, [dict objectForKey:key]);
}

Matt shows in his fantastic blog, how to create a ordered dictionary, that essentially uses another array to keep the order just as I showed here: OrderedDictionary: Subclassing a Cocoa class cluster