在 coredata 中保存对象时出错

Question

这是我的代码：

- (IBAction) saveData
{
    NSLog(@"saveData");
    [self dismissKeyboard];
    Fugitive *job = (Fugitive *)[NSEntityDescription insertNewObjectForEntityForName:@"Fugitive" inManagedObjectContext:managedObjectContext];
    job.name = txtName.text;



    NSError *error;

    // here's where the actual save happens, and if it doesn't we print something out to the console
    if (![managedObjectContext save:&error])
    {
        NSLog(@"Problem saving: %@", [error localizedDescription]);
    }

    // **** log objects currently in database ****
    // create fetch object, this object fetch's the objects out of the database
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Fugitive" inManagedObjectContext:managedObjectContext];
    [fetchRequest setEntity:entity];
    NSArray *fetchedObjects = [managedObjectContext executeFetchRequest:fetchRequest error:&error];

    NSURL *storeURL = [[NSBundle mainBundle] URLForResource:@"iBountyHunter" withExtension:@"momd"];

    id globalStore = [[managedObjectContext persistentStoreCoordinator] persistentStoreForURL:storeURL];


    [managedObjectContext assignObject:job toPersistentStore:globalStore];

    for (NSManagedObject *info in fetchedObjects)
    {
        NSLog(@"Job Name: %@", [info valueForKey:@"name"]);

    }
    [fetchRequest release];
[self.navigationController dismissModalViewControllerAnimated:YES];
}

在控制台中，我收到此错误：保存问题：操作无法完成。 （可可错误1570。） 新对象在表格视图中创建，但未保存，因此重新启动应用程序时，该对象消失

Answer 1

- (void)saveContext
{

    NSError *error = nil;
    NSManagedObjectContext *managedObjectContext = self.managedObjectContext;

    if (managedObjectContext != nil)
    {
        if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error])
        {
         NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
            abort();
        } 
    }
}


- (NSManagedObjectContext *)managedObjectContext
{
    if (__managedObjectContext != nil)
    {
        return __managedObjectContext;
    }

    NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
    if (coordinator != nil)
    {
        __managedObjectContext = [[NSManagedObjectContext alloc] init];
        [__managedObjectContext setPersistentStoreCoordinator:coordinator];
    }
    return __managedObjectContext;
}

- (NSManagedObjectModel *)managedObjectModel
{
    if (__managedObjectModel != nil)
    {
        return __managedObjectModel;
    }
    NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"iBountyHunter" withExtension:@"momd"];
    __managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];    
    return __managedObjectModel;
}

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
    if (__persistentStoreCoordinator != nil)
    {
        return __persistentStoreCoordinator;
    }

    NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"iBountyHunter.sqlite"];

    NSError *error = nil;

    NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption, [NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil];


    __persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
    if (![__persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:options error:&error])
    {



    __persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
    if (![__persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:options error:&error])
    {
               NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }    

    return __persistentStoreCoordinator;
}