Cells in UITableView going blank after the view loads - core-data

Question

I am calling data from web service storing it into CoreData and then putting it into an array that I am using to populate the tableview. When the view loads I am deleting all the data held in the entity in CoreData as the data from the web service will be updated frequently and potentially from multiple platforms. Without the delete code everything worked fine (except old data would build up in CoreData) but as soon as I implemented the deleteEntityData call I got this weird thing happening on the simulator. The data appears and then immediately disappears almost as if the delete code is being called before and after the tableview loads. Checking with NSLogs the code appears to be firing in the right order (and at least according to the NSLogs the delete code is not firing twice)..
Here is a link to a screencast so you can see what I am seeing on the simulator.
http://youtu.be/kvDynYQPln8
Code for the main methods in my tableview are below:
- (void)viewDidLoad{
[super viewDidLoad];
[self setUpData];
}
- (void) deleteEntityData {
//Delete All Old Exlpore View Entities in Core Data
NSLog(#"Delete code being called");
NSManagedObjectContext *context = [self managedObjectContext];
NSFetchRequest *fetch = [[NSFetchRequest alloc] init];
[fetch setEntity:[NSEntityDescription entityForName:#"HomeView" inManagedObjectContext:context]];
[fetch setIncludesPropertyValues:NO];
NSError *error = nil;
NSArray *entities = [context executeFetchRequest:fetch error:&error];
for (NSManagedObject * exploreView in entities) {
[context deleteObject:exploreView];
}
if (![context save:&error]) {
NSLog(#"Can't Save! %# %#", error, [error localizedDescription]);
};
[self.tableView reloadData];
}
- (void) setUpData {
//Initialize AFHTTPRequestOperationManager with Dribbble API base URL
_operationManager = [[AFHTTPRequestOperationManager alloc] initWithBaseURL:[NSURL URLWithString:#"http://www.karmo.com/home/news"]];
[_operationManager GET:#"?user_id=XXXX" parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) {
//Success - Runs if connection is made and data recieved
[self deleteEntityData];
//Extrat parsed JSON file into objects to prepare for Core Data import -- Should verify if I can skip and go directly into Core Data
NSManagedObjectContext *context = [self managedObjectContext];
for (int i = 0; i < [[responseObject valueForKey:#"userBeliefs"] count]; i++) {
NSString * type = #"user";
NSString * userFirstName = [[[[responseObject valueForKey:#"userBeliefs"]objectAtIndex:i] valueForKey:#"user"] valueForKey:#"firstName"];
NSString * userLastName = [[[[responseObject valueForKey:#"userBeliefs"]objectAtIndex:i] valueForKey:#"user"] valueForKey:#"lastName"];
NSString * userID = [[[[responseObject valueForKey:#"userBeliefs"]objectAtIndex:i] valueForKey:#"user"] valueForKey:#"_id"];
NSString * topicID = [[[[responseObject valueForKey:#"userBeliefs"]objectAtIndex:i] valueForKey:#"topic"] valueForKey:#"_id"];
NSString * title = [[[[responseObject valueForKey:#"userBeliefs"]objectAtIndex:i] valueForKey:#"topic"] valueForKey:#"title"];
NSString * vote = [[[responseObject valueForKey:#"userBeliefs"]objectAtIndex:i] valueForKey:#"vote"];
NSString * voice = [[[responseObject valueForKey:#"userBeliefs"]objectAtIndex:i] valueForKey:#"voice"];
NSString * beliefID = [[[responseObject valueForKey:#"userBeliefs"]objectAtIndex:i] valueForKey:#"_id"];
NSNumber * nPoints = #([[[[responseObject valueForKey:#"userBeliefs"]objectAtIndex:i] valueForKey:#"nPoints"]intValue]);
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:#"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"];
NSDate *updatedAt = [dateFormat dateFromString:[[[responseObject valueForKey:#"userBeliefs"]objectAtIndex:i] valueForKey:#"updatedAt"]];
NSManagedObject *newHome = [NSEntityDescription insertNewObjectForEntityForName:#"HomeView" inManagedObjectContext:context];
[newHome setValue:type forKey:#"type"];
[newHome setValue:userFirstName forKey:#"userFirstName"];
[newHome setValue:userLastName forKey:#"userLastName"];
[newHome setValue:userID forKey:#"userID"];
[newHome setValue:topicID forKey:#"topicID"];
[newHome setValue:title forKey:#"title"];
[newHome setValue:vote forKey:#"vote"];
[newHome setValue:voice forKey:#"voice"];
[newHome setValue:beliefID forKey:#"beliefID"];
[newHome setValue:nPoints forKey:#"nPoints"];
[newHome setValue:updatedAt forKey:#"updatedAt"];
}
for (int i = 0; i < [[responseObject valueForKey:#"followeeBeliefs"] count]; i++) {
NSUInteger arrayCount = [[[responseObject valueForKey:#"followeeBeliefs"] objectAtIndex:i] count];
NSUInteger subtract = 2;
NSUInteger finalCount = arrayCount - subtract;
for (int ii = 0; ii < finalCount; ii++) {
NSString * type = #"followee";
NSString * followeeUserID = [[[responseObject valueForKey:#"followeeBeliefs"]objectAtIndex:i] valueForKey:#"followee"];
NSString * connectionID = [[[responseObject valueForKey:#"followeeBeliefs"]objectAtIndex:i] valueForKey:#"_id"];
NSString * userFirstName = [[[[[responseObject valueForKey:#"followeeBeliefs"]objectAtIndex:i] valueForKey:[#(ii) stringValue]] valueForKey:#"user"] valueForKey:#"firstName"];
NSString * userLastName = [[[[[responseObject valueForKey:#"followeeBeliefs"]objectAtIndex:i] valueForKey:[#(ii) stringValue]] valueForKey:#"user"] valueForKey:#"lastName"];
NSString * userID = [[[[[responseObject valueForKey:#"followeeBeliefs"]objectAtIndex:i] valueForKey:[#(ii) stringValue]] valueForKey:#"user"] valueForKey:#"_id"];
NSString * topicID = [[[[[responseObject valueForKey:#"followeeBeliefs"]objectAtIndex:i] valueForKey:[#(ii) stringValue]] valueForKey:#"topic"] valueForKey:#"_id"];
NSString * title = [[[[[responseObject valueForKey:#"followeeBeliefs"]objectAtIndex:i] valueForKey:[#(ii) stringValue]] valueForKey:#"topic"] valueForKey:#"title"];
NSString * vote = [[[[responseObject valueForKey:#"followeeBeliefs"]objectAtIndex:i] valueForKey:[#(ii) stringValue]] valueForKey:#"vote"];
NSString * voice = [[[[responseObject valueForKey:#"followeeBeliefs"]objectAtIndex:i] valueForKey:[#(ii) stringValue]] valueForKey:#"voice"];
NSString * beliefID = [[[[responseObject valueForKey:#"followeeBeliefs"]objectAtIndex:i] valueForKey:[#(ii) stringValue]] valueForKey:#"_id"];
NSNumber * nPoints = #([[[[[responseObject valueForKey:#"followeeBeliefs"]objectAtIndex:i] valueForKey:[#(ii) stringValue]] valueForKey:#"nPoints"]intValue]);
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:#"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"];
NSDate *updatedAt = [dateFormat dateFromString:[[[[responseObject valueForKey:#"followeeBeliefs"]objectAtIndex:i] valueForKey:[#(ii) stringValue]] valueForKey:#"updatedAt"]];
NSManagedObject *newHome = [NSEntityDescription insertNewObjectForEntityForName:#"HomeView" inManagedObjectContext:context];
[newHome setValue:type forKey:#"type"];
[newHome setValue:followeeUserID forKey:#"followeeUserID"];
[newHome setValue:connectionID forKey:#"connectionID"];
[newHome setValue:userFirstName forKey:#"userFirstName"];
[newHome setValue:userLastName forKey:#"userLastName"];
[newHome setValue:userID forKey:#"userID"];
[newHome setValue:topicID forKey:#"topicID"];
[newHome setValue:title forKey:#"title"];
[newHome setValue:vote forKey:#"vote"];
[newHome setValue:voice forKey:#"voice"];
[newHome setValue:beliefID forKey:#"beliefID"];
[newHome setValue:nPoints forKey:#"nPoints"];
[newHome setValue:updatedAt forKey:#"updatedAt"];
}
}
for (int i = 0; i < [[responseObject valueForKey:#"topics"] count]; i++) {
NSString * type = #"topic";
NSString * topicID = [[[responseObject valueForKey:#"topics"]objectAtIndex:i] valueForKey:#"_id"];
NSString * category = [[[responseObject valueForKey:#"topics"]objectAtIndex:i] valueForKey:#"category"];
NSString * title = [[[responseObject valueForKey:#"topics"]objectAtIndex:i] valueForKey:#"title"];
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:#"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"];
NSDate *updatedAt = [dateFormat dateFromString:[[[responseObject valueForKey:#"topics"]objectAtIndex:i] valueForKey:#"updatedAt"]];
NSString * eventTitle = [[[[responseObject valueForKey:#"topics"]objectAtIndex:i] valueForKey:#"lastEvent"] valueForKey:#"title"];
NSString * eventBody = [[[[responseObject valueForKey:#"topics"]objectAtIndex:i] valueForKey:#"lastEvent"] valueForKey:#"body"];
NSString * eventID = [[[[responseObject valueForKey:#"topics"]objectAtIndex:i] valueForKey:#"lastEvent"] valueForKey:#"_id"];
NSDate * eventUpdatedAt = [dateFormat dateFromString:[[[[responseObject valueForKey:#"topics"]objectAtIndex:i] valueForKey:#"lastEvent"] valueForKey:#"updatedAt"]];
NSDate * eventCreatedAt = [dateFormat dateFromString:[[[[responseObject valueForKey:#"topics"]objectAtIndex:i] valueForKey:#"lastEvent"] valueForKey:#"updatedAt"]];
NSManagedObject *newHome = [NSEntityDescription insertNewObjectForEntityForName:#"HomeView" inManagedObjectContext:context];
[newHome setValue:type forKey:#"type"];
[newHome setValue:topicID forKey:#"topicID"];
[newHome setValue:category forKey:#"category"];
[newHome setValue:title forKey:#"title"];
[newHome setValue:updatedAt forKey:#"updatedAt"];
[newHome setValue:eventTitle forKey:#"eventTitle"];
[newHome setValue:eventBody forKey:#"eventBody"];
[newHome setValue:eventID forKey:#"eventID"];
[newHome setValue:eventUpdatedAt forKey:#"eventUpdatedAt"];
[newHome setValue:eventCreatedAt forKey:#"eventCreatedAt"];
}
NSError *error = nil;
if (![context save:&error]) {
NSLog(#"Can't Save! %# %#", error, [error localizedDescription]);
}
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
//Failure
NSLog(#"Failed to fetch shots from Karmo API!");
UIAlertView *alert = [[UIAlertView alloc]initWithTitle:#"Unable to Connect"
message:#"We were not able to connect to the karmo database. Some data may be out of date."
delegate:self
cancelButtonTitle:#"Ok"
otherButtonTitles: nil];
[alert show];
} ];
[self fetchData];}
- (void) fetchData {
[homeSortData removeAllObjects];
[homeTableData removeAllObjects];
// Fetch the recipes from persistent data store
NSManagedObjectContext *managedObjectContext = [self managedObjectContext];
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] initWithEntityName:#"HomeView"];
homeSortData = [[managedObjectContext executeFetchRequest:fetchRequest error:nil] mutableCopy];
NSSortDescriptor *dateDescriptor = [NSSortDescriptor
sortDescriptorWithKey:#"updatedAt"
ascending:YES];
NSMutableArray * descriptors = [[NSArray arrayWithObjects:dateDescriptor, nil]mutableCopy];
homeTableData = [[homeSortData sortedArrayUsingDescriptors:descriptors]mutableCopy];
[self.tableView reloadData];}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
if ([[[homeTableData objectAtIndex:indexPath.row] valueForKey:#"type"] isEqualToString:#"topic"]) {
HomeTopicUpdateTableViewCell *topicCell = (HomeTopicUpdateTableViewCell *) [tableView dequeueReusableCellWithIdentifier:#"Topic" forIndexPath:indexPath];
NSDate * topicDate = [[homeTableData objectAtIndex:indexPath.row] valueForKey:#"updatedAt"];
NSString *currentDateString;
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:#"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"];
currentDateString = [dateFormat stringFromDate:[NSDate date]];
NSDate *currentDate = [dateFormat dateFromString:currentDateString];
NSCalendar *gregorianCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *dayComponents = [gregorianCalendar components:NSDayCalendarUnit
fromDate:topicDate
toDate:currentDate
options:0];
NSString *dayDifference = [NSString stringWithFormat:#"%#d", [#([dayComponents day]) stringValue]];
[topicCell.title setText:[[homeTableData objectAtIndex:indexPath.row] valueForKey:#"title"]];
[topicCell.days setText:dayDifference];
[topicCell.eventTitle setText:[[homeTableData objectAtIndex:indexPath.row]valueForKey:#"eventTitle"]];
return topicCell;
}
if ([[[homeTableData objectAtIndex:indexPath.row] valueForKey:#"type"] isEqualToString:#"user"]) {
HomeBeliefTableViewCell *userCell = (HomeBeliefTableViewCell *) [tableView dequeueReusableCellWithIdentifier:#"User" forIndexPath:indexPath];
NSDate * topicDate = [[homeTableData objectAtIndex:indexPath.row] valueForKey:#"updatedAt"];
NSString *currentDateString;
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:#"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"];
currentDateString = [dateFormat stringFromDate:[NSDate date]];
NSDate *currentDate = [dateFormat dateFromString:currentDateString];
NSCalendar *gregorianCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *dayComponents = [gregorianCalendar components:NSDayCalendarUnit
fromDate:topicDate
toDate:currentDate
options:0];
NSString *dayDifference = [NSString stringWithFormat:#"%#d", [#([dayComponents day]) stringValue]];
NSString *pointCount = [[[homeTableData objectAtIndex:indexPath.row] valueForKey: #"nPoints"]stringValue];
[userCell.title setText:[[homeTableData objectAtIndex:indexPath.row] valueForKey:#"title"]];
[userCell.belief setText:[[homeTableData objectAtIndex:indexPath.row] valueForKey:#"voice"]];
[userCell.points setText:pointCount];
[userCell.profileName setText:#"Me"];
[userCell.days setText:dayDifference];
return userCell;
} else {
HomeFolloweeBeliefTableViewCell *followeeCell = (HomeFolloweeBeliefTableViewCell *) [tableView dequeueReusableCellWithIdentifier:#"Followee" forIndexPath:indexPath];
NSDate * topicDate = [[homeTableData objectAtIndex:indexPath.row] valueForKey:#"updatedAt"];
NSString *currentDateString;
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:#"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"];
currentDateString = [dateFormat stringFromDate:[NSDate date]];
NSDate *currentDate = [dateFormat dateFromString:currentDateString];
NSCalendar *gregorianCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *dayComponents = [gregorianCalendar components:NSDayCalendarUnit
fromDate:topicDate
toDate:currentDate
options:0];
NSString *dayDifference = [NSString stringWithFormat:#"%#d", [#([dayComponents day]) stringValue]];
NSString *fullName = [NSString stringWithFormat:#"%# %#",[[homeTableData objectAtIndex:indexPath.row] valueForKey:#"userFirstName"],[[homeTableData objectAtIndex:indexPath.row] valueForKey:#"userLastName"]];
NSString *pointCount = [[[homeTableData objectAtIndex:indexPath.row] valueForKey: #"nPoints"]stringValue];
[followeeCell.title setText:[[homeTableData objectAtIndex:indexPath.row] valueForKey:#"title"]];
[followeeCell.belief setText:[[homeTableData objectAtIndex:indexPath.row] valueForKey:#"voice"]];
[followeeCell.profileName setText:fullName];
[followeeCell.days setText:dayDifference];
return followeeCell;}}

Answer 1

It seems that in the "success" block in your network call, after parsing the response and saving it in core data, you are not calling [self.tableView reloadData].
reloadData is called in deleteEntityData (That's why you see the data disappearing) and in fetchData, but fetchData most probably executes before the success block finishes, thus the data is not yet saved in core data. Either call [self.tableView reloadData at the end if the success block after saving to core data, or move the call to fetchData to the end of the success block (also after the core data context has been saved)