我有一个主tableViewController，触摸一个按钮self.navigation将推送addItem viewController，点击保存self.navigation并弹出添加VC，然后我们回到主表，我成功添加并保存，也获取，但是当它来获取单元格数，数字返回0，方法如下
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
id <NSFetchedResultsSectionInfo> secInfo = [[self.fetchedResultsController sections] objectAtIndex:section];
NSLog(@"No. of cells determined: %lu", (unsigned long)[secInfo numberOfObjects]);
return[secInfo numberOfObjects];
}
NSLog 给我 0，这是什么问题，这让我很头疼。
这是获取请求：
- (NSFetchedResultsController*) fetchedResultsController {
// Fetch Request
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Goal"
inManagedObjectContext:self.managedObjectContext];
[fetchRequest setEntity:entity];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"title"
ascending:NO];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
// setting _fethcedResultsController
_fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest
managedObjectContext:self.managedObjectContext
sectionNameKeyPath:nil
cacheName:nil];
// setting _fetchedResultsController to self
_fetchedResultsController.delegate = self; // for the tableview updating thing
// Thats it
return _fetchedResultsController;
}
请注意，当我检查项目时，它不是零：
// fetching all items to check how many of them exists
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
[fetchRequest setEntity: [NSEntityDescription entityForName:@"Goal"
inManagedObjectContext:self.managedObjectContext]];
NSManagedObjectContext *moc = self.managedObjectContext;
NSError *fetchError = nil;
NSArray *goals = [moc executeFetchRequest:fetchRequest error:&fetchError];
NSLog(@"No. of goals: %lu", (unsigned long)[goals count]);
// end of check for items