使用magicrecord替代fetchedResultsController代码？

Question

我正在将应用程序的核心数据移至 Magical Record。为了更新 UITableView，我以前有这个代码：

- (NSFetchedResultsController *)fetchedResultsController {

    if (_fetchedResultsController != nil) {
        return _fetchedResultsController;
    }

    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Entry" inManagedObjectContext:[CoreDataStore mainStore].context];
    [fetchRequest setEntity:entity];

    [fetchRequest setFetchBatchSize:20];

    NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"creationDate" ascending:NO];
    NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];

    [fetchRequest setSortDescriptors:sortDescriptors];

    // Use the sectionIdentifier property to group into sections.
    NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:[CoreDataStore mainStore].context sectionNameKeyPath:@"sectionIdentifier" cacheName:@"Root"];
    aFetchedResultsController.delegate = self;
    self.fetchedResultsController = aFetchedResultsController;

    self.fetchedResultsController.delegate = self;

    return _fetchedResultsController;
}

我应该保留这段代码，还是应该使用魔法记录以不同的方式工作？

Answer 1

你可以这样使用：

- (NSFetchedResultsController *)fetchedResultsController {
    if (_fetchedResultsController != nil) {
        return _fetchedResultsController;
    }

    _fetchedResultsController = [NSManagedObject fetchAllGroupedBy:nil withPredicate:nil sortedBy:@"date" ascending:NO delegate:self];

    return _fetchedResultsController;
}

你必须用你的子类替换NSManagedObject。

您可以看到其他选项here（标题底部）。