5
我遇到問題我不知道它來自哪裏,與CoreData有關。在我的數據庫中,a有一組包含元素(使用一對多關係)的類別(帶名稱和說明)。NSFetchedResultsController有0個部分
我想劃分我的表格視圖給出Category
類別的屬性,但是當我嘗試使用sectionNameKeyPath:
來完成時,生成的NSFetchedResultsController
有0個部分。如果我將nil傳遞給這個參數,它有1個部分。
的代碼如下:
- (NSFetchedResultsController*) fetchedResultsController
{
if(fetchedResultsController)
return fetchedResultsController;
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
// Edit the entity name as appropriate.
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Category"
inManagedObjectContext:self.managedObjectContext];
[fetchRequest setEntity:entity];
// Set the batch size to a suitable number.
[fetchRequest setFetchBatchSize:10];
// Edit the sort key as appropriate.
NSSortDescriptor *checkDescriptor = [[NSSortDescriptor alloc] initWithKey:@"checked"
ascending:YES];
NSSortDescriptor *indexDescriptor = [[NSSortDescriptor alloc] initWithKey:@"orderIndex"
ascending:YES];
NSArray *sortDescriptors = @[checkDescriptor, indexDescriptor];
[fetchRequest setSortDescriptors:sortDescriptors];
// Edit the section name key path and cache name if appropriate.
// nil for section name key path means "no sections".
fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest
managedObjectContext:self.managedObjectContext
sectionNameKeyPath:@"checked"
cacheName:nil];
NSError *error = nil;
if (![fetchedResultsController performFetch:&error]) {
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
return nil;
} else {
fetchedResultsController.delegate = self;
return fetchedResultsController;
}
}
它不斷產生0個部分... – gskbyte
你有@synthesize你的fetchedResultsController嗎?我有類似的問題,這是問題。 – Giovanni