objective-c - RestKit 0.20 映射问题

Question

当我发出请求并尝试将响应放入 Core Data 时出现以下错误。

Performing managed object mapping with a nil managed object cache:
Unable to update existing object instances by identification attributes. Duplicate objects     may be created.

我设置了 identifactionAttributes 并使用对象管理器来配置请求操作。而且我仍然收到“无法更新现有对象实例......”

objectMapping = [RKEntityMapping mappingForEntityForName:@"Entity"     inManagedObjectStore:self.managedObjectStore];
            objectMapping.identificationAttributes = @[ @"route_id" ];
            [objectMapping addAttributeMappingsFromDictionary:@{
             @"point_alt" : @"point_alt",
             @"point_lat" : @"point_lat",
             @"point_long" : @"point_long",
             @"location_id" : @"location_id",
             @"route_id" : @"route_id"
             }];


NSMutableURLRequest *request = [[RKObjectManager sharedManager] requestWithObject:nil      method:RKRequestMethodPOST path:path parameters:paramsWithEncr];

RKManagedObjectRequestOperation *operation = [[RKObjectManager sharedManager] managedObjectRequestOperationWithRequest:request   managedObjectContext:self.managedObjectStore.mainQueueManagedObjectContext success:^(RKObjectRequestOperation *operation, RKMappingResult *result) {
        NSLog(@"Loading mapping result: %d", result.count);
    } failure:^(RKObjectRequestOperation *operation, NSError *error) {
        NSLog(@"Fail!");
    }];

Answer 1

我没有配置 Core Data 与对象管理器的集成。如果您遇到同样的问题，您应该这样做:

NSManagedObjectModel *managedObjectModel = [NSManagedObjectModel mergedModelFromBundles:nil];
RKManagedObjectStore *managedObjectStore = [[RKManagedObjectStore alloc] initWithManagedObjectModel:managedObjectModel];
NSString *path = [RKApplicationDataDirectory() stringByAppendingPathComponent:@"Store.sqlite"];
[managedObjectStore addSQLitePersistentStoreAtPath:path fromSeedDatabaseAtPath:nil withConfiguration:nil options:nil error:nil];
[managedObjectStore createManagedObjectContexts];