我在沒有NSFetchedResultsController
的情況下設置了CoreData,並且一切都很好。切換到NSFetchedResultsController
後,嘗試保存圖像時出現奇怪的錯誤。將NSFetchedResultsController添加到項目後出現的問題
這裏是我用來保存圖片代碼:
- (void)saveImage {
NSManagedObjectContext *context = [self managedObjectContext];
TimeTravelFeed *timeTravelFeed = [NSEntityDescription insertNewObjectForEntityForName:@"TimeTravelFeed" inManagedObjectContext:context];
NSData *imageData = UIImageJPEGRepresentation(self.thumbImage, 0.8f);
[timeTravelFeed setValue:imageData forKey:@"imageData"];
NSError *error = nil;
if (![self.managedObjectContext save:&error]) {
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
}
//[tableView reloadData];
}
,這裏是錯誤消息:
-[_PFExternalReferenceData compare:]: unrecognized selector sent to instance 0x1669fb40
2013-12-08 10:09:49.442 Time Travel[830:60b] CoreData: error: Serious application error. Exception was caught during Core Data change processing. This is usually a bug within an observer of NSManagedObjectContextObjectsDidChangeNotification.
-[_PFExternalReferenceData compare:]: unrecognized selector sent to instance 0x1669fb40 with userInfo (null)
2013-12-08 10:09:49.443 Time Travel[830:60b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[_PFExternalReferenceData compare:]: unrecognized selector sent to instance 0x1669fb40'
這裏是NSFetchedResultsController代碼:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
DetailViewController *detailsViewController = [[DetailViewController alloc] init];
[self.navigationController pushViewController:detailsViewController animated:YES];
}
- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller {
[self.tableView beginUpdates];
}
- (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id <NSFetchedResultsSectionInfo>)sectionInfo
atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type {
switch(type) {
case NSFetchedResultsChangeInsert:
[self.tableView insertSections:[NSIndexSet indexSetWithIndex:sectionIndex]
withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeDelete:
[self.tableView deleteSections:[NSIndexSet indexSetWithIndex:sectionIndex]
withRowAnimation:UITableViewRowAnimationFade];
break;
}
}
- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject
atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type
newIndexPath:(NSIndexPath *)newIndexPath {
UITableView *tableView = self.tableView;
switch(type) {
case NSFetchedResultsChangeInsert:
[tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath]
withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeDelete:
[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath]
withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeUpdate:
[self configureCell:[tableView cellForRowAtIndexPath:indexPath]
atIndexPath:indexPath];
break;
case NSFetchedResultsChangeMove:
[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath]
withRowAnimation:UITableViewRowAnimationFade];
[tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath]
withRowAnimation:UITableViewRowAnimationFade];
break;
}
}
- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller {
[self.tableView endUpdates];
}
- (NSFetchedResultsController *)fetchedResultsController {
if (_fetchedResultsController != nil) {
return _fetchedResultsController;
}
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription
entityForName:@"TimeTravelFeed" inManagedObjectContext:managedObjectContext];
[fetchRequest setEntity:entity];
NSSortDescriptor *sort = [[NSSortDescriptor alloc]
initWithKey:@"imageData" ascending:NO];
[fetchRequest setSortDescriptors:[NSArray arrayWithObject:sort]];
[fetchRequest setFetchBatchSize:20];
NSFetchedResultsController *theFetchedResultsController =
[[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest
managedObjectContext:managedObjectContext sectionNameKeyPath:nil
cacheName:@"Root"];
self.fetchedResultsController = theFetchedResultsController;
_fetchedResultsController.delegate = self;
return _fetchedResultsController;
}
我不能看到你的這部分代碼錯誤。也許在「所有Objective-C異常」中設置一個斷點來定位問題。 –
我應該在哪裏調用它?添加NSFEtchedResultsController的代碼後,我不知道需要添加到用於保存圖像的舊代碼塊中?我需要添加什麼? @nhgrif – matthew
NSFetchedResultsController用於在表視圖中顯示Core Data對象,並且完全獨立於* add *對象的方式。正如我所說,你的代碼似乎沒問題,而問題在別的地方。 - 您必須以某種方式查找問題(例如,使用異常斷點)。 –