Question

I have the following code that sorts by ascending.

NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"platform.name" ascending:YES];
    NSMutableArray   *sortedReleases = [NSMutableArray arrayWithArray:[theReleases sortedArrayUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]]];
    [sortDescriptor release];

What I want to do is do a sort where:

1. Show the ones where a sortedRelease is flagged true

2. Sort the rest using acsending (how it is doing it currently)

How would I get about doing that?

Answer 1

The method sortedArrayUsingDescriptors:sortDescriptors is plural and takes an array so it implies you can have multiple sort descriptors which will be applied in the order they appear in the array.

The following code will do the sort how you want providing I understood you right and you have the property sortedRelease.

NSSortDescriptor *sortBySortedRelease = [[NSSortDescriptor alloc] initWithKey:@"sortedRelease" ascending:NO];
NSSortDescriptor *sortByName          = [[NSSortDescriptor alloc] initWithKey:@"platform.name" ascending:YES];

NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortBySortedRelease, sortByName, nil];

[sortBySortedRelease release]; sortBySortedRelease = nil;
[sortByName release]; sortByName = nil;

NSMutableArray *sortedReleases = [NSMutableArray arrayWithArray:[theReleases sortedArrayUsingDescriptors:sortDescriptors]];
[sortDescriptors release]; sortDescriptors = nil;

Here’s the relevant section from the docs for NSArray

- (NSArray *)sortedArrayUsingDescriptors:(NSArray *)sortDescriptors

Parameters
sortDescriptors
An array of NSSortDescriptor objects.

Return Value
A copy of the receiving array sorted as specified by sortDescriptors.

Discussion
The first descriptor specifies the primary key path to be used in sorting the receiving array’s contents. Any subsequent descriptors are used to further refine sorting of objects with duplicate values. See NSSortDescriptor for additional information.