Refreshing table view using core data

Question

I am having issues reloading my core data after inserting a new item I have tried the following however no joy. I was wondering if this could be due to the way i am calling the data? Im very new to this and have been following various tutorials to come this far however im stuck now. I know the viewdidappear is being called as nslog states this however the table is not updated

`- (void)viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];
     [self.tableView reloadData];

    NSLog (@"did appear");
}`

Any Ideas?

//  ViewController.m
//  Core Data

#import "ViewController.h"
#import "AppDelegate.h"

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UINavigationItem *back;
@property (weak, nonatomic) IBOutlet UITableView *tableView;

@property (strong, nonatomic) NSMutableArray *name;
@property (strong, nonatomic) NSMutableArray *phone;

@end

@implementation ViewController


- (void)viewDidLoad
{
    [super viewDidLoad];



    self.name = [[NSMutableArray alloc] init];
    self.phone = [[NSMutableArray alloc] init];

    AppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
    NSManagedObjectContext *context = [appDelegate managedObjectContext];
    NSEntityDescription *entityDesc = [NSEntityDescription entityForName:@"Contact" inManagedObjectContext:context];
    NSFetchRequest *request = [[NSFetchRequest alloc] init];
    [request setEntity:entityDesc];
//    NSPredicate *pred =[NSPredicate predicateWithFormat:@"(name = %@)", @"Vea Software"];
//    [request setPredicate:pred];
    NSManagedObject *matches = nil;

    NSError *error;
    NSArray *objects = [context executeFetchRequest:request
                                              error:&error];

    if ([objects count] == 0)
    {
        NSLog(@"No matches");
    }
    else
    {
        for (int i = 0; i < [objects count]; i++)
        {
            matches = objects[i];
            [self.name addObject:[matches valueForKey:@"name"]];
            [self.phone addObject:[matches valueForKey:@"phone"]];
        }
    }

}

- (void)viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];
     [self.tableView reloadData];

    NSLog (@"did appear");
}


- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}



- (IBAction)add:(id)sender
{
    AppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];

    NSManagedObjectContext *context = [appDelegate managedObjectContext];
    NSManagedObject *newContact;
    newContact = [NSEntityDescription insertNewObjectForEntityForName:@"Contact" inManagedObjectContext:context];

    addentry = self.addtextbox.text;

    [newContact setValue: addentry forKey:@"name"];
    [self.name addObject: addentry];
    [newContact setValue: @"(555) 555 - 5555" forKey:@"phone"];
    [self.phone addObject:@"(555) 555 - 5555"];
    NSError *error;
    [context save:&error];
    [self.tableView reloadData];
}

#pragma Table View

-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return self.name.count;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *cellID = @"cellID";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellID];
    if (cell == nil)
    {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellID];
    }
    cell.textLabel.text = [self.name objectAtIndex:indexPath.row];
    return cell;
}



@end

Answer 1

Take a look at this tutorial http://www.raywenderlich.com/999/core-data-tutorial-for-ios-how-to-use-nsfetchedresultscontroller

You need to rethink the architecture of your view controller. In general, you want to:

• have the view controller load the data, and just "sit there" waiting to receive a notification that things have changed, and reload based on that notification. This is the "UI thread", that should not be blocked by data-access operations

• have your data changes occurring on the background. Modern apps use Grand Central Dispatch to make these operations on the background, but there are other alternatives, like NSOperation, threads, etc.

• Let the NSFetchedResultsController handle the UI updates for you. Let Core Data contexts manage the data consolidation.

These two concepts are key to make things work as they should. Otherwise, you may end up with a mess of code.

Good luck!