ios - iCloud 需要很长时间才能连接到本地商店，并且 iCloud 对上下文所做的更改会影响我的 fetchedResultsController

Question

当我的应用程序加载时，它会发出通知，告知它正在使用本地商店:1 通常需要 4 到 5 分钟才能返回使用本地商店:0。不仅使用 NSNotifications 重新加载似乎不起作用，尽管转到新 View 然后返回。

应用委托(delegate):

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{
    if(![[NSUserDefaults standardUserDefaults] boolForKey:@"firstTime"]){
        UIAlertView *msg = [[UIAlertView alloc] initWithTitle:@"Would You Like to Keep Clients Synced With iCloud" message:nil delegate:self cancelButtonTitle:@"NO" otherButtonTitles:@"YES", nil];
        msg.tag = 101;
        [msg show];

    }
    [self registerForiCloudNotifications];
    UINavigationController *nc = (UINavigationController *)self.window.rootViewController;
    ClientListViewController *iC = (ClientListViewController *)[nc viewControllers][0];
    iC.context = [self managedObjectContext];
    return YES;
}

- (void)applicationWillResignActive:(UIApplication *)application
{
    // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
    // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
}

- (void)applicationDidEnterBackground:(UIApplication *)application
{
    // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later. 
    // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}

- (void)applicationWillEnterForeground:(UIApplication *)application
{
    // Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
}

- (void)applicationDidBecomeActive:(UIApplication *)application
{
    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}

- (void)applicationWillTerminate:(UIApplication *)application
{
    // Saves changes in the application's managed object context before the application terminates.
    [self saveContext];
}

- (void)saveContext
{
    NSError *error = nil;
    NSManagedObjectContext *managedObjectContext = self.managedObjectContext;
    if (managedObjectContext != nil) {
        if ([managedObjectContext hasChanges] && ![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. 
            NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
            abort();
        } 
    }
}

#pragma mark - Core Data stack

// Returns the managed object context for the application.
// If the context doesn't already exist, it is created and bound to the persistent store coordinator for the application.
- (NSManagedObjectContext *)managedObjectContext
{
    if (_managedObjectContext != nil) {
        return _managedObjectContext;
    }

    NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
    if (coordinator != nil) {
        _managedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
        [_managedObjectContext setPersistentStoreCoordinator:coordinator];
    }
    return _managedObjectContext;
}

// Returns the managed object model for the application.
// If the model doesn't already exist, it is created from the application's model.
- (NSManagedObjectModel *)managedObjectModel
{
    if (_managedObjectModel != nil) {
        return _managedObjectModel;
    }
    NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"Benjii" withExtension:@"momd"];
    _managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
    return _managedObjectModel;
}

// Returns the persistent store coordinator for the application.
// If the coordinator doesn't already exist, it is created and the application's store added to it.
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
    if (_persistentStoreCoordinator != nil) {
        return _persistentStoreCoordinator;
    }



    NSError *error = nil;
    _persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
    if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:[self storeURL] options:[self storeOptions] error:&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. 

         Typical reasons for an error here include:
         * The persistent store is not accessible;
         * The schema for the persistent store is incompatible with current managed object model.
         Check the error message to determine what the actual problem was.


         If the persistent store is not accessible, there is typically something wrong with the file path. Often, a file URL is pointing into the application's resources directory instead of a writeable directory.

         If you encounter schema incompatibility errors during development, you can reduce their frequency by:
         * Simply deleting the existing store:
         [[NSFileManager defaultManager] removeItemAtURL:storeURL error:nil]

         * Performing automatic lightweight migration by passing the following dictionary as the options parameter:
         @{NSMigratePersistentStoresAutomaticallyOption:@YES, NSInferMappingModelAutomaticallyOption:@YES}

         Lightweight migration will only work for a limited set of schema changes; consult "Core Data Model Versioning and Data Migration Programming Guide" for details.

         */
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }    

    return _persistentStoreCoordinator;
}
-(NSURL *)storeURL{
    return [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"Benjii.sqlite"];
}
- (void)registerForiCloudNotifications{
    NSLog(@"Registering");
    NSNotificationCenter *notificationCenter = [NSNotificationCenter defaultCenter];
    [notificationCenter addObserver:self
                           selector:@selector(storesWillChange:)
                               name:NSPersistentStoreCoordinatorStoresWillChangeNotification
                             object:self.persistentStoreCoordinator];
    [notificationCenter addObserver:self
                           selector:@selector(storesDidChange:)
                               name:NSPersistentStoreCoordinatorStoresDidChangeNotification
                             object:self.persistentStoreCoordinator];
    [notificationCenter addObserver:self
                           selector:@selector(persistentStoreDidImportUbiquitousContentChanges:)
                               name:NSPersistentStoreDidImportUbiquitousContentChangesNotification
                             object:self.persistentStoreCoordinator];
}

#pragma mark - iCloud Support
//Use these options in your call to addPersistentStore:
-(NSDictionary *)storeOptions{
    NSMutableDictionary *options = [[NSMutableDictionary alloc] init];
    [options setObject:[NSNumber numberWithBool:YES] forKey:NSMigratePersistentStoresAutomaticallyOption];
    [options setObject:[NSNumber numberWithBool:YES] forKey:NSInferMappingModelAutomaticallyOption];
    [options setObject:@"GraniteCloudStore" forKey:NSPersistentStoreUbiquitousContentNameKey];
    return options;
}

- (void) persistentStoreDidImportUbiquitousContentChanges:(NSNotification *)changeNotification{
    NSManagedObjectContext *context = self.managedObjectContext;
    [context performBlock:^{
        [context mergeChangesFromContextDidSaveNotification:changeNotification];
    }];
    [[NSNotificationCenter defaultCenter] postNotificationName:@"Reload" object:nil];
}

- (void) storesWillChange:(NSNotification *)notification {
    NSManagedObjectContext *context = self.managedObjectContext;
    [context performBlockAndWait:^{
        NSError *error;
        if([context hasChanges]){
            BOOL success = [context save:&error];
            if(!success && error){
                //perform error handling
                NSLog(@"%@", [error localizedDescription]);
            }
        }
        [context reset];
    }];
    //Refresh User Interface
    NSLog(@"Stores will change");
}

-(void)storesDidChange:(NSNotification *)notification{
    //Refresh your User Interface
    NSLog(@"Stores did change");
    [[NSNotificationCenter defaultCenter] postNotificationName:@"Reload" object:nil];
}

-(void)migrateiCloudStoreToLocalStore{
    //assuming you only have one store.
    NSPersistentStore *store = [[_persistentStoreCoordinator persistentStores] firstObject];
    NSMutableDictionary *localStoreOptions = [[self storeOptions] mutableCopy];
    [localStoreOptions setObject:@YES forKey:NSPersistentStoreRemoveUbiquitousMetadataOption];
    NSPersistentStore *newStore = [_persistentStoreCoordinator migratePersistentStore:store
                                                                                toURL:[self storeURL]
                                                                              options:localStoreOptions
                                                                             withType:NSSQLiteStoreType
                                                                                error:nil];
    [self reloadStore:newStore];
}

-(void)reloadStore:(NSPersistentStore *)store {
    if(store){
        [_persistentStoreCoordinator removePersistentStore:store error:nil];
    }
    [_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType
                                              configuration:nil
                                                        URL:[self storeURL]
                                                    options:[self storeOptions]
                                                      error:nil];
}


#pragma mark - Application's Documents directory

// Returns the URL to the application's Documents directory.
- (NSURL *)applicationDocumentsDirectory
{
    return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}

#pragma mark - Alert View Delegate

-(void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex{
    if(alertView.tag == 101){
        [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"firstTime"];
        if(buttonIndex != alertView.cancelButtonIndex){
            [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"iCloudSupport"];
        }
    }
    [[NSUserDefaults standardUserDefaults] synchronize];
}
@end

和fetchresultcontroller:

-(NSFetchedResultsController *)clientResultsController{
    if(clientResultsController != nil){
        return clientResultsController;
    }
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] initWithEntityName:@"Client"];
    // NSPredicate *predicate = [NSPredicate predicateWithFormat:@"name beginswith %@"];
    NSSortDescriptor *sort = [[NSSortDescriptor alloc] initWithKey:@"finitial" ascending:YES selector:@selector(localizedCompare:)];
    //[fetchRequest setPredicate:predicate];
    [fetchRequest setSortDescriptors:[NSArray arrayWithObject:sort]];
    NSFetchedResultsController *theFetchedResultController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest
                                                                                                 managedObjectContext:context
                                                                                                   sectionNameKeyPath:@"finitial"
                                                                                                            cacheName:@"Root"];
    self.clientResultsController = theFetchedResultController;
    self.clientResultsController.delegate = self;
    return clientResultsController;
}

和 View Controller 中的观察者:

-(void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];
    [[NSNotificationCenter defaultCenter] addObserverForName:@"Reload"
                                                      object:self
                                                       queue:[NSOperationQueue mainQueue]
                                                  usingBlock:^(NSNotification *note){
                                                      NSLog(@"Reloading");
                                                      [self reloadFetchedResults:note];
                                                  }];

}

抱歉，如果答案真的很简单，我检查了其他类似的问题，但它们要么没有答案，要么已过时(尽管我还是尝试了其中几个)。任何帮助都感激不尽编辑似乎我的观察者没有捕捉到 observerForName:@"Reload"

有谁知道如何将观察者添加到发送此消息的方法中:

PFUbiquitySwitchboardEntryMetadata setUseLocalStorage::CoreData: Ubiquity: mobile~843477F1-43D0-4E72-BD91-26C3276A9212:GraniteCloudStore使用本地存储:0

还注意到如果我等到上面的消息然后旋转屏幕也会导致表格填充但是在该通知之前调用了 persistentStoreCoordinatorDidChange

Answer 1

我在这里遇到了类似的问题，但就我而言，当我将我的应用程序从非 icloud 版本迁移到 iCloud 版本时，现有数据不显示。尽管如果我添加一个新条目，那么一切都会显示出来，并且通过调试，我意识到为什么一切都在显示。

在我的 UITableView 中，我做了以下事情:

- (void)reloadFetchedResults:(NSNotification*)note {
    NSError *error = nil;
    if (![[self fetchedResultsController] performFetch:&error]) {

        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }

    if (note)
    {
        [self.timelineTableView reloadData]; 
    }
}

在我的 viewDidLoad 中:

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reloadFetchedResults:) name:@"RefetchAllDatabaseData" object:[[UIApplication sharedApplication] delegate]];
// In your case, the name would be Reload
- (void)viewDidUnload
{
    [super viewDidUnload];

    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

试试这个 - 我在这里完全是个菜鸟，但这对我来说很有效，可以立即看到变化。