启用 iCloud 时 iOS 应用程序在首次启动时冻结

我在 iOS 应用程序中启用了 iCloud，并且在首次启动应用程序时，当我按下应用程序中的任何视图时，应用程序会冻结大约 5 秒。我跟着this http://timroadley.com/2012/04/03/core-data-in-icloud/在我的应用程序中启用 iCloud 并使用核心数据同步数据的教程。在添加iCloud同步之前我没有这个问题。这只发生在第一次启动时，而不是在应用程序的其他启动时发生。 iCloud 同步确实发生。问题是应用程序冻结。

这是管理我的应用程序委托中的同步的代码。

- (NSURL *)applicationDocumentsDirectory
{
    return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
    /*if (persistentStoreCoordinator == nil) {
        NSURL *storeURL = [NSURL fileURLWithPath:[self dataStorePath]];

        persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:self.managedObjectModel];

        NSError *error;
        if (![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) {
            NSLog(@"Error adding persistent store %@, %@", error, [error userInfo]);
            abort();
        }
    }
    return persistentStoreCoordinator;*/

    [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;

    if ((persistentStoreCoordinator != nil)) {
        return persistentStoreCoordinator;
    }

    persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
    NSPersistentStoreCoordinator *psc = persistentStoreCoordinator;

    // Set up iCloud in another thread:

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

        // ** Note: if you adapt this code for your own use, you MUST change this variable:
        NSString *iCloudEnabledAppID = @"48S27G4A2S.com.maxned.iDownloadBlog";

        // ** Note: if you adapt this code for your own use, you should change this variable:
        NSString *dataFileName = @"DataStore.sqlite";

        // ** Note: For basic usage you shouldn't need to change anything else

        NSString *iCloudDataDirectoryName = @"Data.nosync";
        NSString *iCloudLogsDirectoryName = @"Logs";
        NSFileManager *fileManager = [NSFileManager defaultManager];
        NSURL *localStore = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:dataFileName];
        NSURL *iCloud = [fileManager URLForUbiquityContainerIdentifier:nil];

        if (iCloud)
        {
            //NSLog(@"iCloud is working");

            NSURL *iCloudLogsPath = [NSURL fileURLWithPath:[[iCloud path] stringByAppendingPathComponent:iCloudLogsDirectoryName]];

            /*NSLog(@"iCloudEnabledAppID = %@",iCloudEnabledAppID);
            NSLog(@"dataFileName = %@", dataFileName);
            NSLog(@"iCloudDataDirectoryName = %@", iCloudDataDirectoryName);
            NSLog(@"iCloudLogsDirectoryName = %@", iCloudLogsDirectoryName);
            NSLog(@"iCloud = %@", iCloud);
            NSLog(@"iCloudLogsPath = %@", iCloudLogsPath);*/

            if ([fileManager fileExistsAtPath:[[iCloud path] stringByAppendingPathComponent:iCloudDataDirectoryName]] == NO) {
                NSError *fileSystemError;
                [fileManager createDirectoryAtPath:[[iCloud path] stringByAppendingPathComponent:iCloudDataDirectoryName]
                       withIntermediateDirectories:YES
                                        attributes:nil
                                             error:&fileSystemError];

                if (fileSystemError != nil) {
                    NSLog(@"Error creating database directory %@", fileSystemError);
                }
            }

            NSString *iCloudData = [[[iCloud path]
                                     stringByAppendingPathComponent:iCloudDataDirectoryName]
                                    stringByAppendingPathComponent:dataFileName];

            //NSLog(@"iCloudData = %@", iCloudData);

            NSMutableDictionary *options = [NSMutableDictionary dictionary];
            [options setObject:[NSNumber numberWithBool:YES] forKey:NSMigratePersistentStoresAutomaticallyOption];
            [options setObject:[NSNumber numberWithBool:YES] forKey:NSInferMappingModelAutomaticallyOption];
            [options setObject:iCloudEnabledAppID forKey:NSPersistentStoreUbiquitousContentNameKey];
            [options setObject:iCloudLogsPath forKey:NSPersistentStoreUbiquitousContentURLKey];

            [psc lock];

            [psc addPersistentStoreWithType:NSSQLiteStoreType
                configuration:nil
                URL:[NSURL fileURLWithPath:iCloudData]
                options:options
                error:nil];

            [psc unlock];

        } else {

            NSLog(@"iCloud is NOT working - using a local store");
            NSMutableDictionary *options = [NSMutableDictionary dictionary];
            [options setObject:[NSNumber numberWithBool:YES] forKey:NSMigratePersistentStoresAutomaticallyOption];
            [options setObject:[NSNumber numberWithBool:YES] forKey:NSInferMappingModelAutomaticallyOption];

            [psc lock];

            [psc addPersistentStoreWithType:NSSQLiteStoreType
                configuration:nil
                URL:localStore
                options:options
                error:nil];

            [psc unlock];

        }

        dispatch_async(dispatch_get_main_queue(), ^{
            [[NSNotificationCenter defaultCenter] postNotificationName:@"SomethingChanged" object:self userInfo:nil];
        });
    });

    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;

    return persistentStoreCoordinator;
}

/*- (NSManagedObjectContext *)managedObjectContext
{
    if (managedObjectContext == nil) {
        NSPersistentStoreCoordinator *coordinator = self.persistentStoreCoordinator;
        if (coordinator != nil) {
            managedObjectContext = [[NSManagedObjectContext alloc] init];
            [managedObjectContext setPersistentStoreCoordinator:coordinator];
        }
    }
    return managedObjectContext;
}*/

- (NSManagedObjectContext *)managedObjectContext
{
    if (managedObjectContext != nil) {
        return managedObjectContext;
    }

    NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];

    if (coordinator != nil) {
        NSManagedObjectContext *moc = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];

        [moc performBlockAndWait:^{
            [moc setPersistentStoreCoordinator: coordinator];
            [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(mergeChangesFrom_iCloud:) name:NSPersistentStoreDidImportUbiquitousContentChangesNotification object:coordinator];
        }];
        managedObjectContext = moc;
    }

    return managedObjectContext;
}

- (void)mergeChangesFrom_iCloud:(NSNotification *)notification
{
    //NSLog(@"Merging in changes from iCloud...");

    NSManagedObjectContext* moc = [self managedObjectContext];

    [moc performBlock:^{

        [moc mergeChangesFromContextDidSaveNotification:notification];

        NSNotification* refreshNotification = [NSNotification notificationWithName:@"SomethingChanged"
            object:self
            userInfo:[notification userInfo]];

        [[NSNotificationCenter defaultCenter] postNotification:refreshNotification];
    }];
}

为了解决这个问题，我更改了代码以将其放入另一个线程中。

dispatch_queue_t mainQueue = dispatch_get_main_queue();
        dispatch_async(mainQueue, ^{

            NSFileManager *fileManager = [NSFileManager defaultManager];
            NSURL *localStore = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:dataFileName];
            NSURL *iCloud = [fileManager URLForUbiquityContainerIdentifier:nil];

            if (iCloud)
            {
                //NSLog(@"iCloud is working");

                NSURL *iCloudLogsPath = [NSURL fileURLWithPath:[[iCloud path] stringByAppendingPathComponent:iCloudLogsDirectoryName]];

                /*NSLog(@"iCloudEnabledAppID = %@",iCloudEnabledAppID);
                 NSLog(@"dataFileName = %@", dataFileName);
                 NSLog(@"iCloudDataDirectoryName = %@", iCloudDataDirectoryName);
                 NSLog(@"iCloudLogsDirectoryName = %@", iCloudLogsDirectoryName);
                 NSLog(@"iCloud = %@", iCloud);
                 NSLog(@"iCloudLogsPath = %@", iCloudLogsPath);*/

                if ([fileManager fileExistsAtPath:[[iCloud path] stringByAppendingPathComponent:iCloudDataDirectoryName]] == NO) {
                    NSError *fileSystemError;
                    [fileManager createDirectoryAtPath:[[iCloud path] stringByAppendingPathComponent:iCloudDataDirectoryName]
                           withIntermediateDirectories:YES
                                            attributes:nil
                                                 error:&fileSystemError];

                    if (fileSystemError != nil) {
                        NSLog(@"Error creating database directory %@", fileSystemError);
                    }
                }

                NSString *iCloudData = [[[iCloud path]
                                         stringByAppendingPathComponent:iCloudDataDirectoryName]
                                        stringByAppendingPathComponent:dataFileName];

                //NSLog(@"iCloudData = %@", iCloudData);

                NSMutableDictionary *options = [NSMutableDictionary dictionary];
                [options setObject:[NSNumber numberWithBool:YES] forKey:NSMigratePersistentStoresAutomaticallyOption];
                [options setObject:[NSNumber numberWithBool:YES] forKey:NSInferMappingModelAutomaticallyOption];
                [options setObject:iCloudEnabledAppID forKey:NSPersistentStoreUbiquitousContentNameKey];
                [options setObject:iCloudLogsPath forKey:NSPersistentStoreUbiquitousContentURLKey];

                [psc lock];

                [psc addPersistentStoreWithType:NSSQLiteStoreType
                                  configuration:nil
                                            URL:[NSURL fileURLWithPath:iCloudData]
                                        options:options
                                          error:nil];

                [psc unlock];

            } else {

                NSLog(@"iCloud is NOT working - using a local store");
                NSMutableDictionary *options = [NSMutableDictionary dictionary];
                [options setObject:[NSNumber numberWithBool:YES] forKey:NSMigratePersistentStoresAutomaticallyOption];
                [options setObject:[NSNumber numberWithBool:YES] forKey:NSInferMappingModelAutomaticallyOption];

                [psc lock];

                [psc addPersistentStoreWithType:NSSQLiteStoreType
                                  configuration:nil
                                            URL:localStore
                                        options:options
                                          error:nil];

                [psc unlock];
            }
        });