Question

I create an app with core data on Xcode 3.2.5 and it work fine. But now I install Xcode 4.3.1 and now my data are not saving when I close the app. [context save:&error] – not work any more (it isn’t save data).
If someone have the same problem please tell how to resolve it.

Answer 1

It’s hard to answer without more details but you should have this kind of method in your app :

- (void)saveContext
{
NSError *error = nil;
NSManagedObjectContext *managedObjectContext = self.managedObjectContext;
if (managedObjectContext != nil)
{
    if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error])
    {
        /*
         Replace this implementation with code to handle the error appropriately.

         abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. 
         */
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    } 
}
}

Thus, if there is some error you would get it in console.

Basically, every time you make a change in your data, you should call the saveContext method, not just while you close the app.

Look also for core data evolutions over time, maybe your app was made for another iOS version and your code needs to be updated.