我的 iOS 应用程序出现问题，我收到此错误：
“NSObjectInaccessibleException - CoreData could not fulfill a fault”
当我更新数据库时，我从另一个线程执行此操作，并且在该线程中有此方法：
@interface UpdateDatabase : NSOperation
@property (nonatomic,copy) NSString *name;
@end
@implementation UpdateDatabase
- (void)mergeChanges:(NSNotification *)notification
{
AppDelegate *appController = (AppDelegate *)[[UIApplication sharedApplication] delegate];
NSManagedObjectContext *mainContext = [appController managedObjectContext];
// Merge changes into the main context on the main thread
[mainContext performSelectorOnMainThread:@selector(mergeChangesFromContextDidSaveNotification:)
withObject:notification
waitUntilDone:YES];
}
- (void)main {
AppDelegate *appController = (AppDelegate *)[[UIApplication sharedApplication] delegate];
self.managedObjectContext = [[NSManagedObjectContext alloc] init];
[self.managedObjectContext setUndoManager:nil];
[self.managedObjectContext setPersistentStoreCoordinator: [appController persistentStoreCoordinator]];
// Register context with the notification center
NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];
[nc addObserver:self
selector:@selector(mergeChanges:)
name:NSManagedObjectContextDidSaveNotification
object:self.managedObjectContext];
[self checkForUpdate:self.name];
}
- (NSFetchedResultsController *)fetchedResultsController
{
if (__fetchedResultsController != nil) {
return __fetchedResultsController;
}
// Set up the fetched results controller.
// Create the fetch request for the entity.
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
// Edit the entity name as appropriate.
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Serial" inManagedObjectContext:self.managedObjectContext];
[fetchRequest setEntity:entity];
// Set the batch size to a suitable number.
[fetchRequest setFetchBatchSize:20];
// Edit the sort key as appropriate.
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"sectionNumber" ascending:NO];
NSArray *sortDescriptors = [NSArray arrayWithObjects:sortDescriptor, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
// Edit the section name key path and cache name if appropriate.
// nil for section name key path means "no sections".
NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:@"sectionNumber" cacheName:nil];
aFetchedResultsController.delegate = self;
self.fetchedResultsController = aFetchedResultsController;
NSError *error = nil;
if (![self.fetchedResultsController performFetch:&error]) {
/*
Replace this implementation with code to handle the error appropriately.
abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
*/
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
}
return __fetchedResultsController;
}
- (void)checkForUpdate:(NSString *)name
{
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Serial" inManagedObjectContext:self.managedObjectContext];
[fetchRequest setEntity:entity];
//Controllo prima che la serie di cui voglio fare l'aggiornamento non sia in download, e non stia facendo già un aggiornamneto (caso mai per qualche strana ragione non ne siano partiti 2), prendo solo le altre.
[fetchRequest setPredicate:[NSPredicate predicateWithFormat:@"%K == %@", @"serialName",self.name]];
NSError *error;
NSArray *fetchedObjects = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];
for (NSManagedObject *info in fetchedObjects) {
//i update the object
}
if (![self.managedObjectContext save:&error]) {
// Replace this implementation with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate.
// You should not use this function in a shipping application, although it may be useful
// during development. If it is not possible to recover from the error, display an alert
// panel that instructs the user to quit the application by pressing the Home button.
//
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
}
}
@end
我为核心数据数据库中的每个元素启动一个新的 nsoperation，然后在我有 UITableView 的视图中，我有这个：
- (NSFetchedResultsController *)fetchedResultsController
{
if (__fetchedResultsController != nil) {
return __fetchedResultsController;
}
// Set up the fetched results controller.
// Create the fetch request for the entity.
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
// Edit the entity name as appropriate.
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Serial" inManagedObjectContext:self.managedObjectContext];
[fetchRequest setEntity:entity];
// Set the batch size to a suitable number.
[fetchRequest setFetchBatchSize:20];
// Edit the sort key as appropriate.
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"sectionNumber" ascending:NO];
NSSortDescriptor *numberDayDescriptor = [[NSSortDescriptor alloc] initWithKey:@"numberOfDays" ascending:YES];
NSSortDescriptor *serialNameDescriptor = [[NSSortDescriptor alloc] initWithKey:@"serialName" ascending:YES];
NSArray *sortDescriptors = [NSArray arrayWithObjects:sortDescriptor,numberDayDescriptor,serialNameDescriptor, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
// Edit the section name key path and cache name if appropriate.
// nil for section name key path means "no sections".
NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:@"sectionNumber" cacheName:@"Master"];
aFetchedResultsController.delegate = self;
self.fetchedResultsController = aFetchedResultsController;
NSError *error = nil;
if (![self.fetchedResultsController performFetch:&error]) {
/*
Replace this implementation with code to handle the error appropriately.
abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
*/
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
}
return __fetchedResultsController;
}
- (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];
}
有时应用程序崩溃，有时不崩溃，我该如何处理这个错误？我在 SO 上阅读了一些关于这个问题的问题，有人谈论删除 fetchbatchsize 和缓存，你怎么看？我哪里错了？
编辑：
我已经编辑了代码。