小编Sér*_*gio的帖子

我有一个像这样的coredata模型设置:

TileList <->> TileListOrder
TileListOrder <<-> Tile

并创建了一个NSFetchedResultsController:

NSPredicate* predicate = [NSPredicate predicateWithFormat:@"tile <> nil AND tileList <> nil AND tile.removed == 0 AND  tileList.removed == 0"];
NSSortDescriptor* sortTileListDescriptor = [[[NSSortDescriptor alloc] initWithKey:@"tileList.order" ascending:YES] autorelease];
NSSortDescriptor* sortTileDescriptor = [[[NSSortDescriptor alloc] initWithKey:@"order" ascending:YES] autorelease];

NSFetchRequest* fetchRequest = [[NSFetchRequest alloc] init];
[fetchRequest setPredicate:predicate];

[fetchRequest setSortDescriptors:sortDescriptors];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"TileListOrder" inManagedObjectContext:coreManagedObjectContext];
[fetchRequest setEntity:entity];

NSFetchedResultsController* fetchedResults = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest
                                                                                 managedObjectContext:coreManagedObjectContext
                                                                                   sectionNameKeyPath:@"tileList.order"
                                                                                            cacheName:nil];

我还在辅助NSManagedObjectContext上导入数据并将这些更改合并回来,如下所示:

- (void) localContextDidSave:(NSNotification*) notification {
        dispatch_sync(dispatch_get_main_queue(), ^{
    [coreManagedObjectContext mergeChangesFromContextDidSaveNotification:notification]; …