iphone – NSFetchedResultsController错误：

2023年7月31日 240次阅读

Afetr使用NSFetchedResultsController将新记录插入我的CoreData存储区,当我尝试在分组的UITableView中显示数据时,应用程序崩溃时出现以下错误“

NSFetchedResultsController ERROR: The fetched object at index 5 has an out of order section name 'Navigation. Objects must be sorted by section name'

我已将section键值添加到sortDescriptors,但它没有帮助.这是我的代码：

- (NSFetchedResultsController *)fetchedResultsController {

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

/*
 Set up the fetched results controller.
 */
// Create the fetch request for the entity.
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
// Edit the entity name as appropriate.
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Item" inManagedObjectContext:managedObjectContext];
[fetchRequest setEntity:entity];

// Set the batch size to a suitable number.
[fetchRequest setFetchBatchSize:20];

// Edit the sort key as appropriate.
NSSortDescriptor *sortByGroupName = [[NSSortDescriptor alloc] initWithKey:@"group.groupName" ascending:NO];
NSSortDescriptor *sortByIsMandatory = [[NSSortDescriptor alloc] initWithKey:@"isMandatory" ascending:NO];
NSSortDescriptor *sortByItemName = [[NSSortDescriptor alloc] initWithKey:@"itemName" ascending:NO];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortByGroupName, sortByIsMandatory, sortByItemName, nil];

[fetchRequest setSortDescriptors:sortDescriptors];

// Edit the section name key path and cache name if appropriate.
// nil for section name key path means "no sections".
NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:managedObjectContext sectionNameKeyPath:@"group.groupName" cacheName:@"Root"];
aFetchedResultsController.delegate = self;
self.fetchedResultsController = aFetchedResultsController;

[aFetchedResultsController release];
[fetchRequest release];
[sortDescriptors release];
[sortDescriptors release];

return fetchedResultsController;

}

我在这里错过了什么？

谢谢 –

JK

最佳答案 卫生署！发现我的问题：我过度发布了sortDescriptors

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