从数据库中提出 Friend 目标,条件是匹配NSFetchedResultsController给出的user部分。如下:
- (NSFetchedResultsController *)fetchedFriendsResultsController
{
if (_fetchedFriendsResultsController != nil) {
return _fetchedFriendsResultsController;
}
//Get the correct array of friends for that user
NSFetchRequest *fetchRequestItems = [[NSFetchRequest alloc] init];
NSEntityDescription *entityItem = [NSEntityDescription entityForName:@"Friend" inManagedObjectContext:self.managedObjectContext];
[fetchRequestItems setEntity:entityItem];
User* myUser = [DataBaseManager getCurrentUser:managedObjectContext];
[fetchRequestItems setPredicate:[NSPredicate predicateWithFormat:@"user == %@", myUser]];
//Sort by name descending
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:NO];
NSArray *sortDescriptors = [NSArray arrayWithObjects:sortDescriptor, nil];
[fetchRequestItems setSortDescriptors:sortDescriptors];
NSFetchedResultsController *fetchedItemsResultsController =[[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequestItems managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:@"Root"];
_fetchedFriendsResultsController = fetchedItemsResultsController;
return _fetchedFriendsResultsController;
}
此代码运行正常,所有的friend都成功按字母顺序递减排列。
现在我需要一个特殊的friend对象,名字不是按照字母顺序。然后将它们排在其他friend之前。
判断条件是where 'name' == @"SPECIFIC_NAME"。
应该怎么实现?是不是要将这个特殊case添加到分类描述符或者Predicate中?
谢谢