RestKit：无法使用 coredata 执行映射

我正在使用rest kit 0.20.3和Xcode 5。如果没有核心数据，我可以执行所有rest kit操作，但是当我使用核心数据尝试它时，我什至无法执行GET由于一些问题。我想不通。我是核心数据的新手。所以请帮忙。这是我的代码：

AppDelegate.m

@implementation CardGameAppDelegate

@synthesize managedObjectContext = _managedObjectContext;
@synthesize managedObjectModel = _managedObjectModel;
@synthesize persistentStoreCoordinator = _persistentStoreCoordinator;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    RKLogConfigureByName("RestKit", RKLogLevelWarning);
    RKLogConfigureByName("RestKit/ObjectMapping", RKLogLevelTrace);
    RKLogConfigureByName("RestKit/Network", RKLogLevelTrace);

    RKObjectManager *objectManager = [RKObjectManager managerWithBaseURL:[NSURL URLWithString:@"http://192.168.1.3:3010/"]];


    RKManagedObjectStore *objectStore = [[RKManagedObjectStore alloc] initWithManagedObjectModel:self.managedObjectModel];

    objectManager.managedObjectStore = objectStore;

    RKEntityMapping *playerMapping = [RKEntityMapping mappingForEntityForName:@"Player" inManagedObjectStore:objectStore];
    [playerMapping addAttributeMappingsFromDictionary:@{@"id": @"playerId",
                                                        @"name": @"playerName",
                                                        @"age" : @"playerAge",
                                                        @"created_at": @"createdAt",
                                                        @"updated_at": @"updatedAt"}];



    RKResponseDescriptor *responseDesc = [RKResponseDescriptor responseDescriptorWithMapping:playerMapping method:RKRequestMethodGET pathPattern:@"/players.json" keyPath:nil statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];

    [objectManager addResponseDescriptor:responseDesc];

    PlayersTableViewController *ptvc = (PlayersTableViewController *)self.window.rootViewController;
    ptvc.managedObjectContext = self.managedObjectContext;

    return YES;
}

和playerTableViewController.h的代码

#import <UIKit/UIKit.h>

@interface PlayersTableViewController : UITableViewController <NSFetchedResultsControllerDelegate>

@property (strong, nonatomic) NSFetchedResultsController *fetchedResultsController;
@property (strong, nonatomic) NSManagedObjectContext *managedObjectContext;

@end

和 PlayerTableViewController.m 获取方法：

-(void)loadPlayers{
    [[RKObjectManager sharedManager] getObjectsAtPath:@"/players.json" parameters:nil success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult){
        [self.refreshControl endRefreshing];
    } failure:^(RKObjectRequestOperation *operation, NSError *error) {
        [self.refreshControl endRefreshing];
        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"An Error Has Occurred" message:[error localizedDescription] delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
        [alertView show];
    }];
}

我收到以下错误：

 Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Unable to perform mapping: No `managedObjectContext` assigned. (Mapping response.URL = http://192.168.1.3:3010/players.json)'

仅仅创建是不够的objectStore，您需要完成核心数据堆栈设置的其余部分。您还应该在 RestKit 中执行此操作，而不是在应用程序委托中（这是 Apple 提供的默认配置）。这将类似于（根据您的要求定制）：

NSManagedObjectModel *managedObjectModel = [NSManagedObjectModel mergedModelFromBundles:nil];
RKManagedObjectStore *managedObjectStore = [[RKManagedObjectStore alloc] initWithManagedObjectModel:managedObjectModel];

[managedObjectStore createPersistentStoreCoordinator];

NSString *storePath = [RKApplicationDataDirectory() stringByAppendingPathComponent:@"XXXX.sqlite"];
NSError *error;
NSPersistentStore *persistentStore = [managedObjectStore addSQLitePersistentStoreAtPath:storePath
                                                                 fromSeedDatabaseAtPath:nil
                                                                      withConfiguration:nil
                                                                                options:@{
                                                                                          NSMigratePersistentStoresAutomaticallyOption : @(YES),
                                                                                          NSInferMappingModelAutomaticallyOption : @(YES),
                                                                                              }
                                                                                  error:&error];
NSAssert(persistentStore, @"Failed to add persistent store with error: %@", error);

// Create the managed object contexts
[managedObjectStore createManagedObjectContexts];

managedObjectStore.managedObjectCache = [[RKInMemoryManagedObjectCache alloc] initWithManagedObjectContext:managedObjectStore.persistentStoreManagedObjectContext];