managedObjectContext question - iphone

Question

I have an app which is a UITabBarController, I have defined two subviews
Both tabs have their Class attribute in the Identity Inspector set to UINavigationController.
Now i have managed to get this far with my coding after VERY LONG trials.
- (void)viewDidLoad {
[super viewDidLoad];
myAppDelegate *appDelegate = (myAppDelegate *)[[UIApplication sharedApplication] delegate];
self.managedObjectContext = appDelegate.managedObjectContext;
{
NSError *error = nil;
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
[fetchRequest setEntity:[NSEntityDescription entityForName:#"User" inManagedObjectContext:self.managedObjectContext]];
NSArray *fetchedItems = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];
NSEntityDescription *entityDesc =
[NSEntityDescription entityForName:#"User" inManagedObjectContext:self.managedObjectContext];
// replace the old data with new. this DOESNT WORK
if (fetchedItems.count > 0)
{
Usr *newUsr;
for (newUsr in fetchedItems)
{
if ([newUsr.name isEqualToString:#"Line One"])
{
newUsr.uName = #"Line One (new)";
}
}
}
//add a new default data. THIS ADDS DATA TO MY TABLEVIEW BUT IT DOESNT SAVE THEM TO THE SQLITE
User *addedDefaultdata = nil;
addedDefaultdata = [[User alloc] initWithEntity:entityDesc insertIntoManagedObjectContext:self.managedObjectContext];
addedDefaultdata.name = #"Added new 1";
[addedDefaultdata release];
}
NSError *error = nil;
if (![User.managedObjectContext save:&error]) {
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
abort();
}
}
and my appdelegate looks like this:
- (void)applicationDidFinishLaunching:(UIApplication *)application {
[application setStatusBarStyle:UIStatusBarStyleBlackOpaque];
[window addSubview:navigationController.view];
[window makeKeyAndVisible];
}
now I cannot quire the "User" at all! although i get no errors or warnings!
Any suggestions would be much appreciated!
Thanks

Answer 1

It seems that you may be asking how to update to CoreData?
If so, you need to use the save: method on NSManagedObjectContext, like this:
NSError *error;
[managedObjectContent save:&error];
if (error) {
...
}