5
我遇到问题我不知道它来自哪里,与CoreData有关。在我的数据库中,a有一组包含元素(使用一对多关系)的类别(带名称和说明)。NSFetchedResultsController有0个部分
我想划分我的表格视图给出Category
类别的属性,但是当我尝试使用sectionNameKeyPath:
来完成时,生成的NSFetchedResultsController
有0个部分。如果我将nil传递给这个参数,它有1个部分。
的代码如下:
- (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;
}
}
它不断产生0个部分... – gskbyte
你有@synthesize你的fetchedResultsController吗?我有类似的问题,这是问题。 – Giovanni