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我正在使用NSFetchedResultsController填充我的UITableViewController的内容。刷新和删除后台线程错误（NSFetchedResultsController）内容
我使用的NSOperation从web服务（我使用分离ManagedObjectContext，因为它是另一个线程）
当数据被保存我的视图控制器（至极是NSFetchedResultsControllerDelegate）收集的数据被调用，我合并我的使用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对于NSFetchedResultsControllerDelegate我正在使用的代码从CoreData书籍样本
#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];
}
我的问题是当加载新的内容，其中一些对象删除，我的tableView搞砸了！
然后当我向下滚动，我的tableview是空的（只有4个可见行）仍然在tableview中，否则这是一个空白的滚动视图
在：即使我的countOfRow减少1行仍然可见控制台我可以看到以下消息。
严重的应用程序错误。在调用-controllerDidChangeContent：期间，NSFetchedResultsController的委托捕获到异常。 *** - [NSMutableArray的removeObjectAtIndex：]：索引0超越界限的空数组与用户信息（空）
在我因子评分，这是由于我的NSFetchedResultsController的缓存，但即使我禁用它，我有beggining一样的问题。
有人对如何解决这个问题有想法吗？