我NSFetchedResultsController
用来从中获取数据Core Data
并将它们显示在UITableView
. 我的NSFetchedResultsController
样子是这样的:
- (NSFetchedResultsController *) fetchedResultsController
{
if (_fetchedResultsController != nil)
{
return _fetchedResultsController;
}
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"PlanPreparation"
inManagedObjectContext:_context];
[fetchRequest setEntity:entity];
NSPredicate *pred = [NSPredicate predicateWithFormat:@"plan_id == %@", _planCycleID];
[fetchRequest setPredicate:pred];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects: sortDescriptor, nil];
fetchRequest.sortDescriptors = sortDescriptors;
_fetchedResultsController = [[NSFetchedResultsController alloc]initWithFetchRequest:fetchRequest managedObjectContext:_context sectionNameKeyPath:nil cacheName:nil];
_fetchedResultsController.delegate = self;
// but if there is no results I am making another fetch by another type of NSManagedObject
if (_fetchedResultsController.fetchedObjects.count == 0)
{
NSFetchRequest *fetchRequest1 = [[NSFetchRequest alloc] init];
NSEntityDescription *entity1 = [NSEntityDescription entityForName:@"Preparation"
inManagedObjectContext:_context];
[fetchRequest1 setEntity:entity1];
NSPredicate *pred = [NSPredicate predicateWithFormat:@"ismer == %@", [NSNumber numberWithInt:1]];
[fetchRequest1 setPredicate:pred];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects: sortDescriptor, nil];
fetchRequest1.sortDescriptors = sortDescriptors;
_fetchedResultsController = [[NSFetchedResultsController alloc]initWithFetchRequest:fetchRequest1 managedObjectContext:_context sectionNameKeyPath:nil cacheName:nil];
_fetchedResultsController.delegate = self;
//return _fetchedResultsController;
}
return _fetchedResultsController;
}
如果我在第一次尝试提取后没有检索到某些东西,我需要设置另一个提取。在-cellForRowAtIndexPath
我需要显示数据取决于类型NSManagedObjectObject
:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
if ([[self.fetchedResultsController objectAtIndexPath:indexPath] isKindOfClass:[PlanPreparation2 class]])
{
PlanPreparation2 *planDrug = (PlanPreparation2 *)[self.fetchedResultsController objectAtIndexPath:indexPath];
CDPreparation *prep = (CDPreparation *)[[PTDataManager sharedManager]getDrugByID:planDrug.guid];
cell.textLabel.text = [NSString stringWithFormat:@"%@", prep.name];
}
else
{
CDPreparation *drug = (CDPreparation *)[self.fetchedResultsController objectAtIndexPath:indexPath];
cell.textLabel.text = [NSString stringWithFormat:@"%@", drug.name];
}
return cell;
}
但是日志显示-isKindOfClass:
在这里不起作用,我根本没有引用。
问题:
我怎样才能找出类型NSManagedObjectObject
?