从DetailViewController弹出后重新加载TableView数据

Question

How can I reload my tableView data after I click back button/pop from my detailViewController (using UINavigationController and push)? I tried reloading my tableView in viewDidAppear but nothing has changed. Below I attached my storyboard so that you guys can have a idea about what my problem is. When I click save, I want all the data to be automatically reloaded to my tableView when I go back to my UITableViewController . How can I achieve this?

http://i.stack.imgur.com/i1YyV.png

Below is my code for saving new data to coreData using saveButton.

- (IBAction)saveButton:(id)sender {
    CoreDataAppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
    NSManagedObjectContext *context = [appDelegate managedObjectContext];
    NSManagedObject *newContact = [NSEntityDescription insertNewObjectForEntityForName:@"Contact" inManagedObjectContext:context];

    NSString *name = self.nameTextfield.text;
    NSString *phoneNumber = self.phoneTextfield.text;

    CoreDataTableViewController *cdtvc = [[CoreDataTableViewController alloc] init];

    [newContact setValue:name forKey:@"name"];
    [cdtvc.name addObject:name];
    [newContact setValue:phoneNumber forKey:@"phone"];
    [cdtvc.phone addObject:phoneNumber];

    NSError *error;
   [context save:&error];
   [cdtvc.tableView reloadData];
}

Answer 1

You are reloading the tableView of another instance of your CoreDataTableViewController . With this line:

 CoreDataTableViewController *cdtvc = [[CoreDataTableViewController alloc] init]; 

you create a new CoreDataTableViewController instance but when you pop the current view controller from the navigation stack another instance will be visible whose table view has not received the message -reloadData .

To fix this replace the above line with this code:

NSArray *navigationStack = [self.navigationController viewControllers];
NSInteger previousViewControllerIndex = navigationStack.count - 2;
CoreDataTableViewController *cdtvc = [navigationStack objectAtIndex:previousViewControllerIndex];

and see if it does the trick. (Now cdtv is a reference to the original view controller on the navigation stack.)