RESTKit: NSFetchedResultsController does not populate tableView after recreating the managedObjectStore - uitableview

Question

I build my TabBar programmatically and based on if the User is loggedIn, I set
[self.window setRootViewController:home];
Here is the code I call in:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
if (![Persistence loggedIn])
{
[self showLoginScreen];
}
else
{
SignupBase *login = [STLoginSignupBase new];
[login loginUserwithUsername:[Persistence username] andPassword:[Persistence authPass] requestByNewUser:NO completionBlock:^(NSError *error)
{
if (!error)
{
[login loginSuccess];
[self showTabBarScreen];
}
else
{
[STAlertViewUtils showAlert:#"" :error.localizedDescription :kButtonTitleDismiss];
[self showLoginScreen];
}
}];
}
-(void)showTabBarScreen
{
dispatch_async(dispatch_get_main_queue(), ^{
TabBarVC *tabBarVC = [[TabBarVC alloc]init];
[self.window setRootViewController:tabBarVC];
});
}
-(void)showLoginScreen
{
dispatch_async(dispatch_get_main_queue(), ^{
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:#"STLoginSignup" bundle:nil];
HomeVC *homeVC = (HomeVC *)[storyboard instantiateViewControllerWithIdentifier:[HomeVC storyboardID]];
UINavigationController *home = [[UINavigationController alloc]initWithRootViewController:homeVC];
[self.window setRootViewController:home];
});
}
In the TabBar, the first tab "Inbox" is a tableViewController managed with NSFetchedResultsController. When I launch the app for the first time, all the objects are fetched and displayed in the tableView beautifully; however, when I logout and login back in, and "Inbox" is reloaded, I get a blank tableView. Zero objects are fetched locally and even if RESTkit fetches objects, they don't appear in the tableView. When I stop the app in the simulator and relaunch it, all the objects are fetched locally and remotely, and appear in the tableView as they should!
Here is how I logout from the Profile tab (different tab):
- (void)logoutWithCompletionBlock:(void(^)(void))completionBlock
{
[Persistence setLoggedInStatus:NO];
RKObjectManager *objectManager = [self getObjectManager];
[objectManager.HTTPClient clearAuthorizationHeader];
AppDelegate *delegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
NSManagedObjectContext *managedObjectContext = delegate.managedObjectStore.mainQueueManagedObjectContext;
[managedObjectContext reset];
[delegate deregisterWithUrbanAirship];
if (completionBlock)
{
completionBlock();
}
}
After I log back in the App, "Inbox" tab viewController is loaded again.
In my "Inbox" loadView which gets called, I have the following code:
- (void)loadView
{
[self getManagedObjectFromAppDelegate]
}
- (void)getManagedObjectFromAppDelegate
{
AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
[appDelegate setupCoreDataWithRESTKit];
self.objectManager = [self getObjectManager];
self.objectManager.managedObjectStore = appDelegate.managedObjectStore;
self.objectManager.managedObjectStore.managedObjectCache = appDelegate.managedObjectStore.managedObjectCache;
self.managedObjectContext = self.objectManager.managedObjectStore.mainQueueManagedObjectContext;
}
This is the code in [AppDelegate setupCoreDataWithRESTKit];
- (RKManagedObjectStore *)setupCoreDataWithRESTKit
{
NSError * error;
NSURL * modelURL = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:#"App" ofType:#"momd"]];
NSManagedObjectModel * managedObjectModel = [[[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL] mutableCopy];
self.managedObjectStore = [[RKManagedObjectStore alloc] initWithManagedObjectModel:managedObjectModel];
[self.managedObjectStore createPersistentStoreCoordinator];
NSArray * searchPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString * documentPath = [searchPaths objectAtIndex:0];
NSPersistentStore * persistentStore = [self.managedObjectStore addSQLitePersistentStoreAtPath:[NSString stringWithFormat:#"%#/App%#.sqlite", documentPath, [Persistence username]] fromSeedDatabaseAtPath:nil withConfiguration:nil options:[self optionsForSqliteStore] error:&error];
NSAssert(persistentStore, #"Failed to add persistent store with error: %#", error);
NSLog(#"Path: %#", [NSString stringWithFormat:#"%#/App%#.sqlite", documentPath, [Persistence username]]);
if(!persistentStore){
NSLog(#"Failed to add persistent store: %#", error);
}
[self.managedObjectStore createManagedObjectContexts];
return self.managedObjectStore;
}
Please note that each user has a different .sqlite file loaded based on their username: i.e. AppUserName. So when I logout and log back in if it's a same user, then the same file is created/loaded. If it's a different user, then a different name file is created/loaded.
Question: Why does NSFetchedResultsController displays an empty tableView after I logout and log back in, but it works fine when I launch the app the first time?
*EDIT *
I changed and tried the code below but the problem persists:
- (void)logoutWithCompletionBlock:(void(^)(void))completionBlock
{
[Persistence setLoggedInStatus:NO];
RKObjectManager *objectManager = [self getObjectManager];
[objectManager.HTTPClient clearAuthorizationHeader];
AppDelegate *delegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
NSManagedObjectContext *managedObjectContext = delegate.managedObjectStore.mainQueueManagedObjectContext;
[self clearManagedObjectContext:managedObjectContext];
[delegate deregisterWithUrbanAirship];
if (completionBlock)
{
completionBlock();
}
}
- (void)clearManagedObjectContext:(NSManagedObjectContext*)managedObjectContext
{
NSFetchRequest * fetch = [[NSFetchRequest alloc] init];
[fetch setEntity:[NSEntityDescription entityForName:#"EntityA" inManagedObjectContext:managedObjectContext]];
NSMutableArray *result = [NSMutableArray arrayWithArray:[managedObjectContext executeFetchRequest:fetch error:nil]];
for (id entityA in result)
{
[managedObjectContext deleteObject:entityA];
}
[result removeAllObjects];
[fetch setEntity:[NSEntityDescription entityForName:#"EntityB" inManagedObjectContext:managedObjectContext]];
result = [NSMutableArray arrayWithArray:[managedObjectContext executeFetchRequest:fetch error:nil]];
for (id entityB in result)
{
[managedObjectContext deleteObject:entityB];
}
[result removeAllObjects];
[fetch setEntity:[NSEntityDescription entityForName:#"EntityC" inManagedObjectContext:managedObjectContext]];
result = [NSMutableArray arrayWithArray:[managedObjectContext executeFetchRequest:fetch error:nil]];
for (id entityC in result)
{
[managedObjectContext deleteObject:entityC];
}
[result removeAllObjects];
[managedObjectContext saveToPersistentStore:nil];
}

Answer 1

You shouldn't be doing [managedObjectContext reset]; unless you tear down the persistent store that is backing the main thread context (so, tear down the whole Core Data stack and destroy the SQLite file).
Either correct this or just loop over the things you want to delete in the context and save the changes up to the (parent) persistent context.