我正在使用我自己的 JSON 数据关注 restkit 的概述教程。
如教程中所述，我使用的是主表视图样板。根据我的实现，我能够在控制台中显示映射，但我无法在我的表视图单元格中将正确答案显示为文本标签。我很感激，如果有人可以向我解释为什么我没有得到单元格标签中的文本。
这是我为单元格标签文本指定的地方
- (void)configureCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath
{
NSManagedObject *object = [self.fetchedResultsController objectAtIndexPath:indexPath];
cell.textLabel.text = [[object valueForKey:@"CorrectAnswer"] description];
NSLog(@"This is what i am looking for: %@", [object valueForKey:@"CorrectAnswer"]);
}
这是我的控制台结果
2013-10-16 05:07:31.963 Quizi[27422:a0b] I restkit:RKLog.m:34 RestKit logging initialized...
2013-10-16 05:07:32.281 Quizi[27422:a0b] T restkit.network:RKObjectRequestOperation.m:178 GET 'https://xxx.xxx./':
request.headers=(null)
request.body=(null)
2013-10-16 05:07:32.777 Quizi[27422:1003] T restkit.network:RKResponseMapperOperation.m:451 Mapping HTTP response to nil target object...
2013-10-16 05:07:32.781 Quizi[27422:1003] W restkit.core_data:RKManagedObjectMappingOperationDataSource.m:243 Performing managed object mapping with a nil managed object cache:
Unable to update existing object instances by identification attributes. Duplicate objects may be created.
2013-10-16 05:07:32.783 Quizi[27422:1003] W restkit.object_mapping:RKMapperOperation.m:99 Adding mapping error: No mappable values found for any of the attributes or relationship mappings
2013-10-16 05:07:32.788 Quizi[27422:3407] T restkit.network:RKObjectRequestOperation.m:248 GET 'https://xxx.xxx/22' (200 OK / 0 objects) [request=0.4945s mapping=0.0117s total=0.5176s]:
response.headers={
"Cache-Control" = "max-age=100";
"Content-Encoding" = gzip;
"Content-Type" = "application/json; charset=utf-8";
"DWAS-Handler-Name" = "System.Web.Http.WebHost.HttpControllerHandler";
Date = "Wed, 16 Oct 2013 12:07:34 GMT";
Etag = "\"dbc1a97b-e968-4a2a-a697-77328a8d5b94\"";
Server = "Microsoft-IIS/8.0";
"Set-Cookie" = "ARRAffinity=ba0ce9e0d0d8ad0cd8b963604bd90760f5428ad8490fed51bd3786d0fe9002e3;Path=/;Domain=somedomain, WAWebSiteSID=a474e52a3f1f49f48da74b52968824b9; Path=/; HttpOnly";
"Transfer-Encoding" = Identity;
Vary = "Accept-Encoding";
"X-AspNet-Version" = "4.0.30319";
"X-Powered-By" = "ASP.NET, ARR/2.5, ASP.NET";
}
response.body={"some response body here"}
这是我在主表视图中的获取结果控制器
- (NSFetchedResultsController *)fetchedResultsController
{
if (_fetchedResultsController != nil) {
return _fetchedResultsController;
}
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
// Edit the entity name as appropriate.
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Items" inManagedObjectContext:self.managedObjectContext];
[fetchRequest setEntity:entity];
// Set the batch size to a suitable number.
[fetchRequest setFetchBatchSize:20];
// Edit the sort key as appropriate.
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"CorrectAnswer" ascending:NO];
NSArray *sortDescriptors = @[sortDescriptor];
[fetchRequest setSortDescriptors:sortDescriptors];
// Edit the section name key path and cache name if appropriate.
// nil for section name key path means "no sections".
NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:@"Master"];
aFetchedResultsController.delegate = self;
self.fetchedResultsController = aFetchedResultsController;
NSError *error = nil;
if (![self.fetchedResultsController performFetch:&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();
}
return _fetchedResultsController;
}
这就是我映射的方式
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
self.navigationItem.leftBarButtonItem = self.editButtonItem;
UIBarButtonItem *addButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(insertNewObject:)];
self.navigationItem.rightBarButtonItem = addButton;
RKManagedObjectStore *managedObjectStore = [RKManagedObjectStore defaultStore];
RKEntityMapping *entityMapping = [RKEntityMapping mappingForEntityForName:@"Items" inManagedObjectStore:managedObjectStore];
[entityMapping addAttributeMappingsFromDictionary:@{@"Id":@"iD",
@"PicUrl":@"picURL",
@"CorrectAnswer":@"correctAnswer",
@"Difficulty":@"difficulty",
@"CategoryId":@"categoryID",
@"CategoryName":@"categoryName",
@"AccountId":@"accountID"
}];
RKLogConfigureByName("RestKit/Network", RKLogLevelTrace);
RKResponseDescriptor *responseDescriptor =[RKResponseDescriptor responseDescriptorWithMapping:entityMapping method:RKRequestMethodGET pathPattern:nil keyPath:nil statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"https:someDomain"]];
RKManagedObjectRequestOperation *managedObjectRequestOperation =[[RKManagedObjectRequestOperation alloc]initWithRequest:request responseDescriptors:@[responseDescriptor]];
managedObjectRequestOperation.managedObjectContext = self.managedObjectContext;
[[NSOperationQueue currentQueue]addOperation:managedObjectRequestOperation];
}