用对象订购NSArray

Question

I have an NSDictionary with the following data:

(lldb) po allFriends
{
    71685207018702188 =     {
        id = 71685207018702188;
        name = "mikeziri ";
        username = mi;
    };
    93374822540641772 =     {
        id = 93374822540641772;
        name = "Alan Weclipse";
        username = zuka;
    };
    96553685978449395 =     {
        id = 96553685978449395;
        name = "Monica Weclipse";
        username = amonica;
    };
    96556113096345076 =     {
        id = 96556113096345076;
        name = Xavier;
        username = branko;
    };
    97017008427632119 =     {
        id = 97017008427632119;
        name = "Dario Weclipse";
        username = tarzan;
    };
}

I'm sorting these objects based on the name , if they don't have a name , i will use the username . To do that, i create a new NSDictionary with the name and id and at the end of the method i sort them by name . The code to sort them is the following:

- (NSArray*)orderFriends
{
    NSMutableDictionary* newFriendsDict = [[NSMutableDictionary alloc] init];

    for (int i=0; i<[allFriends count];i++)
    {
        NSMutableDictionary* friendsDict = [[NSMutableDictionary alloc] init];
        NSDictionary* friend = [allFriends objectForKey:[NSString stringWithFormat:@"%@", [sortedKeysFriends objectAtIndex:i]]];

        if ([[friend objectForKey:@"name"] length] != 0)
        {
            [friendsDict setObject:[friend objectForKey:@"id"] forKey:@"id"];
            [friendsDict setObject:[NSString stringWithFormat:@"%@", [friend objectForKey:@"name"]] forKey:@"name"];
        }
        else
        {
            [friendsDict setObject:[friend objectForKey:@"id"] forKey:@"id"];
            [friendsDict setObject:[NSString stringWithFormat:@"%@", [friend objectForKey:@"username"]] forKey:@"name"];
        }

        [newFriendsDict setObject:friendsDict forKey:[NSNumber numberWithInt:i]];
    }

    NSArray* sp = nil;
    sp = [[newFriendsDict allValues] sortedArrayUsingComparator:^(id obj1, id obj2){
        NSString *one = [NSString stringWithFormat:@"%@", [obj1 objectForKey:@"name"]];
        NSString *two = [NSString stringWithFormat:@"%@", [obj2 objectForKey:@"name"]];

        return [one compare:two];
    }];

    return sp;
}

The problem is that the end result is wrong:

(lldb) po sp
<__NSArrayI 0x160491a0>(
{
    id = 93374822540641772;
    name = "Alan Weclipse";
},
{
    id = 97017008427632119;
    name = "Dario Weclipse";
},
{
    id = 96553685978449395;
    name = "Monica Weclipse";
},
{
    id = 96556113096345076;
    name = Xavier;
},
{
    id = 71685207018702188;
    name = "mikeziri ";
},
)

Answer 1

Case sensitive. make all string small or big.

Answer 2

You could also just change
return [one compare:two];
to
return [one compare:two options: options:NSCaseInsensitiveSearch];

Than it will be ordered alphabetically, no matter if upper or lower case...

Answer 3

Several things: There is no reason to build different dictionaries in order to sort, and good reason NOT to do so.

You already found the method sortedArrayUsingComparator. That takes a block that is used to compare pairs of objects, and returns a sorted array. You can use that method to implement any sorting criteria you want.

I would suggest writing a comparator block that compares the name properties of your objects unless it's blank, and uses username if that's blank. It would only be a few lines of code:

NSArray *sortedFriends = [[allFriends allValues] sortedArrayUsingComparator:
                          ^(NSDictionary *obj1, NSDictionary *obj2)
{
    NSString* key1 = obj1[@"name"] ? obj1[@"name"] : obj1[@"username"];
    NSString* key2 = obj2[@"name"] ? obj2[@"name"] : obj2[@"username"];
    return [key1 caseInsensitiveCompare: key2];
}];

EDIT: I just noticed (from your edit of my post) that you are starting from a dictionary, not an array. So what you want to do is to create a sorted array of all the values in the dictionary? Is it acceptable to discard the keys for all the items in your dictionary, and end up with a sorted array of the values?

The other thing you could do would be to build an array of the dictionary keys, sorted based on your sort criteria. Then you could use the array of keys to fetch the items from your dictionary in sorted order.