Question

Sort descriptors with custom blocks are not supported in iOS6, so I need to figure out another way to do this:

A Student entity can belong to one of two sets: confirmedClasses or pendingClasses. I want to fetch Students with the following predicate:

[fetchRequest setPredicate:[NSPredicate predicateWithFormat:@"ANY confirmedClasses.classId== %@
    OR ANY pendingClasses.classId == %@", currentClass.classId, currentClass.classId]];

So a user can be either as a confirmed student in the class or a pending student. What I want is to sort the results so that all confirmed students are listed first, and pending students are listed after all confirmed students.

Any idea how I could accomplish this?

Answer 1

I’d just use two predicates, compound for fetch, and use to filter results:

NSPredicate *confirmed = [NSPredicate predicateWithFormat:@"ANY confirmedClasses.classId== %@,currentClass.classId];

NSPredicate *pending = [NSPredicate predicateWithFormat:@"ANY pendingClasses.classId== %@,currentClass.classId];

NSArray *predicates = [NSArray arrayWithObjects:confirmed,pending,nil];

[fetchRequest setPredicate:[NSCompoundPredicate orPredicateWithSubpredicates:predicates]];

//Perform fetch into an array called 'results'

NSArray *filteredConfirmed = [results filteredArrayUsingPredicate:confirmed];
NSArray *filteredPending = [results filteredArrayUsingPredicate:pending];

NSArray *sortedResult = [filteredConfirmed arrayByAddingObjectsFromArray:filteredPending];