Question

我需要使用RestKit映射灵活的数据结构，但我没有运气。

我有一个活动资源，其中包含一系列额外子资源。每个额外资源都包含密钥和值。当然，由于最后这些不是真正的资源，因此对他们来说没有任何意义。

此处有一个活动资源的示例：

  {
            "_id": "xxxxx",
            ...
            "extras": [
                {
                    "key": "group",
                    "value": "xxxx"
                },
                {
                    "key": "name",
                    "value": "xxxxx"
                },
                {
                    "key": "asd",
                    "value": "xxx"
                }
            ]
  }

这里有我用于映射的代码：

- (RKEntityMapping *)activityMapping {
RKEntityMapping * activityMapping = [RKEntityMapping mappingForEntityForName:@"SSActivity"
                                                        inManagedObjectStore:self.managedObjectStore];
[activityMapping addAttributeMappingsFromDictionary:@{
                                                      @"_id"         : @"activityId"
                                                      }];

[activityMapping addRelationshipMappingWithSourceKeyPath:@"extras" mapping:[self activityExtraMapping]];

activityMapping.identificationAttributes = @[@"activityId"];

return activityMapping;
}

- (RKEntityMapping *)activityExtraMapping {
   RKEntityMapping * activityExtraMapping = [RKEntityMapping mappingForEntityForName:@"SSActivityExtra"
                                                        inManagedObjectStore:self.managedObjectStore];
[activityExtraMapping addAttributeMappingsFromDictionary:@{
                                                           @"key" : @"key",
                                                           @"value" : @"value"
                                                           }];
return activityExtraMapping;
}

SSActivityExtra 类只包含键和值字符串属性，而 SSActivity 包含 extra < / em> property。

@property (nonatomic, retain) NSSet * extras;

现在，只要restkit映射请求，我就会收到以下异常：

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSArrayM _stateFlags]: unrecognized selector sent to instance 0xadc4560' *** First throw call stack: ( 0 CoreFoundation 0x0358b5e4 __exceptionPreprocess + 180 1 libobjc.A.dylib 0x0330e8b6 objc_exception_throw + 44 2 CoreFoundation 0x03628903 -[NSObject(NSObject) doesNotRecognizeSelector:] + 275 3 CoreFoundation 0x0357b90b ___forwarding___ + 1019 4 CoreFoundation 0x0357b4ee _CF_forwarding_prep_0 + 14 5 CoreData 0x00bad03e -[NSRelationshipDescription(_NSInternalMethods) _nonPredicateValidateValue:forKey:inObject:error:] + 270 6 CoreData 0x00babdeb -[NSManagedObject(_NSInternalMethods) _validateValue:forProperty:andKey:withIndex:error:] + 379 7 CoreData 0x00c3b408 -[NSManagedObject validateValue:forKey:error:] + 136 8 Foundation 0x013f12c0 -[NSObject(NSKeyValueCoding) validateValue:forKeyPath:error:] + 435 9 SeeApp 0x00207cee -[RKMappingOperation validateValue:atKeyPath:] + 398 10 SeeApp 0x00208434 -[RKMappingOperation shouldSetValue:forKeyPath:usingMapping:] + 1108 11 SeeApp 0x0020dd77 -[RKMappingOperation mapOneToManyRelationshipWithValue:mapping:] + 2503 12 SeeApp 0x002101cf -[RKMappingOperation applyRelationshipMappings] + 6815 13 SeeApp 0x00212540 -[RKMappingOperation main] + 4224 14 Foundation 0x01405829 -[__NSOperationInternal _start:] + 671 15 Foundation 0x01382558 -[NSOperation start] + 83 16 SeeApp 0x001ffb25 -[RKMapperOperation mapRepresentation:toObject:atKeyPath:usingMapping:metadata:] + 1957 17 SeeApp 0x001ff14c __63-[RKMapperOperation mapRepresentations:atKeyPath:usingMapping:]_block_invoke + 460 18 CoreFoundation 0x035855eb __NSArrayEnumerate + 571 19 CoreFoundation 0x03585196 -[NSArray enumerateObjectsWithOptions:usingBlock:] + 102 20 CoreFoundation 0x035850a5 -[NSArray enumerateObjectsUsingBlock:] + 53 21 SeeApp 0x001fedfc -[RKMapperOperation mapRepresentations:atKeyPath:usingMapping:] + 2364 22 SeeApp 0x00200c10 -[RKMapperOperation mapRepresentationOrRepresentations:atKeyPath:usingMapping:] + 560 23 SeeApp 0x00201672 -[RKMapperOperation mapSourceRepresentationWithMappingsDictionary:] + 2210 24 SeeApp 0x0020203b -[RKMapperOperation main] + 1403 25 Foundation 0x01405829 -[__NSOperationInternal _start:] + 671 26 Foundation 0x01382558 -[NSOperation start] + 83 27 SeeApp 0x002542a7 __73-[RKManagedObjectResponseMapperOperation performMappingWithObject:error:]_block_invoke + 4887 28 CoreData 0x00bccfef developerSubmittedBlockToNSManagedObjectContextPerform + 95 29 libdispatch.dylib 0x045474b0 _dispatch_client_callout + 14 30 libdispatch.dylib 0x04534778 _dispatch_barrier_sync_f_invoke + 58 31 libdispatch.dylib 0x04534422 dispatch_barrier_sync_f + 89 32 CoreData 0x00bccf1f -[NSManagedObjectContext performBlockAndWait:] + 127 33 SeeApp 0x00252a91 -[RKManagedObjectResponseMapperOperation performMappingWithObject:error:] + 993 34 SeeApp 0x00250413 -[RKResponseMapperOperation main] + 2371 35 Foundation 0x01405829 -[__NSOperationInternal _start:] + 671 36 Foundation 0x01382558 -[NSOperation start] + 83 37 Foundation 0x01407af4 __NSOQSchedule_f + 62 38 libdispatch.dylib 0x045474b0 _dispatch_client_callout + 14 39 libdispatch.dylib 0x0453507f _dispatch_queue_drain + 452 40 libdispatch.dylib 0x04534e7a _dispatch_queue_invoke + 128 41 libdispatch.dylib 0x04535e1f _dispatch_root_queue_drain + 83 42 libdispatch.dylib 0x04536137 _dispatch_worker_thread2 + 39 43 libsystem_pthread.dylib 0x048d3dab _pthread_wqthread + 336 44 libsystem_pthread.dylib 0x048d7cce start_wqthread + 30 ) libc++abi.dylib: terminating with uncaught exception of type NSException

我知道这可能与this类似，但我认为不是，建议的解决方案没有帮助。

这里发生了什么？我已经在这方面苦苦挣扎了两天。

编辑12-12：添加了模型屏幕截图

SSActivityExtra数据模型

SSActivity数据模型

Answer 1

我能够以这种方式解决类似问题：我没有在Core Data中配置一对多的关系。配置完成后，问题就解决了。

Answer 2

不确定这是否会导致异常，但此代码错误：

[activityExtraMapping addAttributeMappingsFromDictionary:@{
                                                       @"key" : @"key",
                                                       @"value" : @"value"
                                                       }];

应该是：

[activityExtraMapping addAttributeMappingsFromDictionary:@{
                                                       @"key" : @"extraKey",
                                                       @"value" : @"extraValue"
                                                       }];

异常可能是由于extraKey和extraValue属性是非可选的，因此当RestKit尝试保存模型时会引发异常......

RestKit数据映射导致应用程序崩溃

2 个答案: