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我正在使用NSFetchedResultsController填充我的UITableViewController的內容。刷新和刪除後臺線程錯誤（NSFetchedResultsController）內容
我使用的NSOperation從web服務（我使用分離ManagedObjectContext，因爲它是另一個線程）
當數據被保存我的視圖控制器（至極是NSFetchedResultsControllerDelegate）收集的數據被調用，我合併我的使用mergeChangesFromContextDidSaveNotification
#pragma mark -
#pragma mark Parsers delegate
- (void)parserWillSave:(id)parser{
TopNewsParser *emp = (TopNewsParser *)parser;
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(parserContextDidSave:) name:NSManagedObjectContextDidSaveNotification object:emp.managedObjectContext];
[NSFetchedResultsController deleteCacheWithName:@"aLaUne"];
}
- (void)parserDidSave:(id)parser{
TopNewsParser *emp = (TopNewsParser *)parser;
[[NSNotificationCenter defaultCenter] removeObserver:self name:NSManagedObjectContextDidSaveNotification object:emp.managedObjectContext];
}
/**
Notification from the add controller's context's save operation. This is used to update the fetched results controller's managed object context with the new book instead of performing a fetch (which would be a much more computationally expensive operation).
*/
- (void)parserContextDidSave:(NSNotification*)saveNotification {
DLog(@"");
NSManagedObjectContext *fetchContext = [_fetchedResultsController managedObjectContext];
// Merging changes causes the fetched results controller to update its results
[fetchContext performSelectorOnMainThread:@selector(mergeChangesFromContextDidSaveNotification:)
withObject:saveNotification
waitUntilDone:YES];
}
MOCS對於NSFetchedResultsControllerDelegate我正在使用的代碼從CoreData書籍樣本
#pragma mark -
#pragma mark NSFetchedResultsControllerDelegate
- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller {
// The fetch controller is about to start sending change notifications, so prepare the table view for updates.
[self.tableView beginUpdates];
}
- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type newIndexPath:(NSIndexPath *)newIndexPath {
//ALog(@"indexPath: %@ newIndexPath : %@ | type : %d # %@",indexPath,newIndexPath,type,anObject);
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];
// Reloading the section inserts a new row and ensures that titles are updated appropriately.
[tableView reloadSections:[NSIndexSet indexSetWithIndex:newIndexPath.section] withRowAnimation:UITableViewRowAnimationFade];
break;
}
}
- (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)controllerDidChangeContent:(NSFetchedResultsController *)controller {
UIBarButtonItem *reloadButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemRefresh
target:self
action:@selector(refreshTableViewContent)];
reloadButton.accessibilityLabel = @"Reload";
self.navigationItem.leftBarButtonItem = reloadButton;
// The fetch controller has sent all current change notifications, so tell the table view to process all updates.
[self.tableView endUpdates];
}
我的問題是當加載新的內容，其中一些對象刪除，我的tableView搞砸了！
然後當我向下滾動，我的tableview是空的（只有4個可見行）仍然在tableview中，否則這是一個空白的滾動視圖
在：即使我的countOfRow減少1行仍然可見控制檯我可以看到以下消息。
嚴重的應用程序錯誤。在調用-controllerDidChangeContent：期間，NSFetchedResultsController的委託捕獲到異常。 *** - [NSMutableArray的removeObjectAtIndex：]：索引0超越界限的空數組與用戶信息（空）
在我因子評分，這是由於我的NSFetchedResultsController的緩存，但即使我禁用它，我有beggining一樣的問題。
有人對如何解決這個問題有想法嗎？