RestKit 0.20 - CoreData：错误：未能呼吁NSManagedObject类指

我遇到了，我似乎无法找到解决办法的一个新问题......这里是我的RestKit代码，继Twitter的核心数据例如：

//
// RESTKIT
//

// restkit object manager
NSString *baseURL = @"http://test1.website.com";
RKObjectManager *objectManager = [RKObjectManager managerWithBaseURL:[NSURL URLWithString:baseURL]];

// enable activity indicator
[AFNetworkActivityIndicatorManager sharedManager].enabled = YES;

// managed object model
NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"AppName" withExtension:@"momd"];
NSManagedObjectModel *managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
// NSLog(@"managed object model: %@", managedObjectModel);

// managed object store
RKManagedObjectStore *managedObjectStore = [[RKManagedObjectStore alloc] initWithManagedObjectModel:managedObjectModel];
objectManager.managedObjectStore = managedObjectStore;
// NSLog(@"managed object store: %@", managedObjectStore);

// persistent store
NSError *error;
NSString *storePath = [RKApplicationDataDirectory() stringByAppendingPathComponent:@"AppName.sqlite"];
NSPersistentStore *persistentStore = [managedObjectStore addSQLitePersistentStoreAtPath:storePath fromSeedDatabaseAtPath:nil withConfiguration:nil options:nil error:&error];
if (error) {
    NSLog(@"unresolved error %@, %@", error, [error userInfo]);
    abort();
}
// NSLog(@"persistent store coordinator: %@", managedObjectStore.persistentStoreCoordinator);
// NSLog(@"persistent store: %@", persistentStore);

// managed object contexts
[managedObjectStore createManagedObjectContexts];
// NSLog(@"managed object context: %@", managedObjectStore.mainQueueManagedObjectContext);

// managed object cache
managedObjectStore.managedObjectCache = [[RKInMemoryManagedObjectCache alloc] initWithManagedObjectContext:managedObjectStore.mainQueueManagedObjectContext];
// NSLog(@"mangaged object cache: %@", managedObjectStore.managedObjectCache);

//
// entity mapping
//

// album entity mapping
RKEntityMapping *albumEntityMapping = [RKEntityMapping mappingForEntityForName:@"Album" inManagedObjectStore:managedObjectStore];
albumEntityMapping.identificationAttributes = @[ @"identifier" ];
[albumEntityMapping addAttributeMappingsFromDictionary:@{ @"title" : @"title" }];

//
// response descriptor
//

// album response descriptor
[objectManager addResponseDescriptor:[RKResponseDescriptor responseDescriptorWithMapping:albumEntityMapping pathPattern:[NSString stringWithFormat:@"/albums/display/%@/%@", userInfo[@"userID"], userInfo[@"apiKey"]] keyPath:nil statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)]];

我请求经由一个UITableViewController类的API的信息：

- (void)loadObjectsFromResourcePath:(NSString *)resourcePath;
{
   [[RKObjectManager sharedManager] getObjectsAtPath:resourcePath parameters:nil success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) {
        NSLog(@"mapping result: %@", [mappingResult array]);
        [self stopLoading];
    } failure:^(RKObjectRequestOperation *operation, NSError *error) {
        NSLog(@"error: %@", error);
        [self stopLoading];
    }];
}

然而，与此代码我收到以下错误：

2012-12-05 17:08:14.830 AppName Alpha[1310:907] I restkit:RKLog.m:34 RestKit logging initialized...
2012-12-05 17:08:15.107 AppName Alpha[1310:907] resource path: albums/display/102/drrrbSAt6RFLsgHaKiiB6kBIyYRyzxLYinL84Kba
2012-12-05 17:08:15.113 AppName Alpha[1310:907] I restkit.support:RKMIMETypeSerialization.m:115 JSON Serialization class 'RKNSJSONSerialization' detected: Registering for MIME Type 'application/json
2012-12-05 17:08:15.118 AppName Alpha[1310:1603] I restkit.network:RKHTTPRequestOperation.m:141 GET 'http://test1.AppName.com/albums/display/102/drrrbSAt6RFLsgHaKiiB6kBIyYRyzxLYinL84Kba'
2012-12-05 17:08:15.122 AppName Alpha[1310:907] error (null), (null)
2012-12-05 17:08:35.333 AppName Alpha[1310:3e13] I restkit.network:RKHTTPRequestOperation.m:158 GET 'http://test1.AppName.com/albums/display/102/drrrbSAt6RFLsgHaKiiB6kBIyYRyzxLYinL84Kba' (200)
2012-12-05 17:08:35.351 AppName Alpha[1310:1507] CoreData: error: Failed to call designated initializer on NSManagedObject class 'AppName Album' 
2012-12-05 17:08:35.355 AppName Alpha[1310:1507] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<AppName 0x1c579380> valueForUndefinedKey:]: the entity (null) is not key value coding-compliant for the key "Title".'
*** First throw call stack:
(0x39e503e7 0x38ea9963 0x39e500d5 0x371f8d81 0x3276cc1d 0xbf545 0xc00f5 0xc0ab9 0xc44c5 0x32791299 0xb738b 0xb6e5f 0xb7ca5 0xb8343 0xb895b 0x32791299 0xf96ef 0xf8c4b 0x32791299 0x328097f7 0x32c38793 0x32c3c657 0x32c3c7d9 0x3312a7f1 0x3312a684)
libc++abi.dylib: terminate called throwing an exception

你可以在这里拿在返回的JSON对象高峰： http://test1.AppName.com/albums/display/102/drrrbSAt6RFLsgHaKiiB6kBIyYRyzxLYinL84Kba

Answer 1:

这表明有人企图，而无需调用相应的核心数据初始化，这可能意味着你得到一个创建对象RKObjectRequestOperation实例，而不是一个的RKManagedObjectRequestOperation 。

我怀疑是响应描述符未能来匹配的URL，这是导致它选错了对象请求的操作方式。您可以通过将一个断点检查这个appropriateObjectRequestOperationWithObject:method:path:parameters:在上面写着几行：

NSArray *matchingDescriptors = RKFilteredArrayOfResponseDescriptorsMatchingPath(self.responseDescriptors, requestPath);
BOOL containsEntityMapping = RKDoesArrayOfResponseDescriptorsContainEntityMapping(matchingDescriptors);
BOOL isManagedObjectRequestOperation = (containsEntityMapping || [object isKindOfClass:[NSManagedObject class]]);

这个逻辑是什么是负责选择操作创建的类型。检查matchingDescriptors包含您所期望的响应描述符，然后检查接下来的两个布尔值。我的猜测是， RKFilteredArrayOfResponseDescriptorsMatchingPath没有返回你所期望的。

Answer 2:

现在已经阅读RKObjectManager类的文档该澄清的基础URL的AF联网处理的处理。如果我读了这首会保存自己一些时间，也提出有关RestKit实例路径不相关的评论。

有匹配的对象和实体映射在内的多个对象的映射与零关键路径和不同的URL的混合问题，发现这个答案确定这可能给别人遇到类似的问题作出贡献的问题说明如下的原因是非常有用的。