我正在尝试在我的 iOS 应用程序中使用 RestKit 0.20 将 json 映射到核心数据对象。我有两种类型的对象:用户和消息。用户有很多消息。消息具有指向用户的字段:'from' 和 'to'。这是我的消息 json:
[
{
"created_at":1358265482867,
"to":"50ed7b4e63e9b80200000009",
"note":"Hello",
"from":"50ee98365315d00200000003",
"_id":"50f57cee11f2b00200000016",
"__v":0
},
{
"created_at":1358265582867,
"to":"50ed7b4e63e9b80200000009",
"note":"Hello 2",
"from":"50ee98365315d00200000003",
"_id":"50f57cee11f2b00200000016",
"__v":0
}
]
我的映射代码如下所示:
// Object mappings
RKEntityMapping *userMapping = [RKEntityMapping mappingForEntityForName:@"User" inManagedObjectStore:managedObjectStore];
userMapping.identificationAttributes = @[@"userId"];
[userMapping addAttributeMappingsFromDictionary:@{
@"_id": @"userId",
@"name": @"name",
@"note": @"headline",
@"photo_url": @"photoUrl"
}];
RKEntityMapping *messageMapping = [RKEntityMapping mappingForEntityForName:@"Message" inManagedObjectStore:managedObjectStore];
messageMapping.identificationAttributes = @[@"messageId"];
[messageMapping addAttributeMappingsFromDictionary:@{
@"_id": @"messageId",
@"note": @"note",
@"created_at": @"createdAt",
@"from": @"from",
@"to" : @"to"
}];
// !!! This code is ok if json contains entire object (but contains only id).
// [messageMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:@"from" toKeyPath:@"from" withMapping:userMapping]];
// [messageMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:@"to" toKeyPath:@"to" withMapping:userMapping]];
RKEntityMapping *messageReversedMapping = [messageMapping inverseMapping];
RKRequestDescriptor *requestDescription = [RKRequestDescriptor requestDescriptorWithMapping:messageReversedMapping objectClass:[Message class] rootKeyPath:nil];
[objectManager addRequestDescriptor:requestDescription];
RKResponseDescriptor *userResponseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:userMapping pathPattern:@"/users" keyPath:nil statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];
[objectManager addResponseDescriptor:userResponseDescriptor];
RKResponseDescriptor *messageResponseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:messageMapping pathPattern:@"/messages" keyPath:nil statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];
[objectManager addResponseDescriptor:messageResponseDescriptor];
型号代码:
@interface Message : NSManagedObject
@property (nonatomic, retain) NSString * note;
@property (nonatomic, retain) NSNumber * createdAt;
@property (nonatomic, retain) NSString * messageId;
@property (nonatomic, retain) User *from;
@property (nonatomic, retain) User *to;
@interface User : NSManagedObject
@property (nonatomic, retain) NSString * email;
@property (nonatomic, retain) NSString * headline;
@property (nonatomic, retain) NSString * lastName;
@property (nonatomic, retain) NSNumber * me;
@property (nonatomic, retain) NSString * name;
@property (nonatomic, retain) NSString * photoUrl;
@property (nonatomic, retain) NSString * userId;
@property (nonatomic, retain) Message *messagesFrom;
@property (nonatomic, retain) Message *messagesTo;
问题是在 json 中,字段“to”和“from”是用户的 id 而不是嵌套对象,因此应用程序崩溃。
我发现了类似的 SO 问题,但仍然无法正常工作。
使用 Objective-C 在 Xcode 中使用 RestKit 映射嵌套 ID
谁能帮我正确设置映射,所以 json 将只包含用户的 ID 而不是嵌套对象?