ios - RestKit复杂而简单的JSON RKObjectMapping几乎可以工作，但是

Question

我一直在研究这个问题。以下是一些发现，将有助于在RestKit中映射此JSON响应

JSON响应对象包含三个顶级对象:
位置是一个数组
cityKey对象
stateKey对象
Since Restkit is written in Objective-C, I looked at it as if I were going to directing映射这些对象并解析出数据

我编写了以下代码来映射Location Class \ Object的NSDictionary部分:

    RKObjectMapping* locationMapping = [RKObjectMapping       mappingForClass:[Location class]];
     [locationMapping addAttributeMappingsFromDictionary:@{
                             @"distance": @"distance",
                             @"major": @"major",
                             @"minor": @"minor" }];

我为整个class \ object位置编写了以下代码://这也应该是NSDictionary

    RKObjectMapping *locationsMapping = RKObjectMapping       mappingforclass: [Locations class]];

This appears to be a mapping array should be a dictionary.

    [locationsMapping addAttributeMappingsFromArray:@[@"locations", @"cityKey",@"stateKey"]];

我看到在将Array用于整个对象Locations时出现错误。这将运行并返回以下内容的部分成功结果:

RKResponseDescriptor *locationDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:locationMapping method:RKRequestMethodAny pathPattern:@"/location" keyPath:nil statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];

    [[RKObjectManager sharedManager]    addResponseDescriptor:responseDescriptor];
    [[RKObjectManager sharedManager]    addResponseDescriptor:locationDescriptor];



[[RKObjectManager sharedManager] postObject:nil path:(_enterLocation) parameters:nil success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) {
     NSLog(@"It Worked: %@", [mappingResult array]);


} failure:^(RKObjectRequestOperation *operation, NSError *error) {
     NSLog(@"It Failed: %@", error);

  }];

This returns the successful responseJSONdata, but mappingResult dictionary returns:

2014-05-07 17:28:39.770 MyApp[163:60b] It Worked: {
    locations =  (
    );

}

The actual JSONOBJECTWITHDATA returned as response.body is:

response.body={
  "locations": [
    {
      "distance": 0.5, 
      "major": 2, 
      "minor": 4, 
      
    }, 
    {
      "distance": 1.0, 
      "major": 2, 
      "minor": 11, 
      
    }
  ], 
  "cityKey": "12", 
  "stateKey": "41"
}

通过阅读，

Will RestKit's dynamic mapping solve this complex JSON mapping?

和

Feeding parsed data to RKMapperOperation throws NSUnknownKeyException

我知道我需要更改RestKit映射的方法。对于复杂的情况

即使在简单的情况下，我也只返回指向该对象的指针。

 RKObjectMapping *statusResponseMapping = [RKObjectMapping mappingForClass:[StatusResponse class]];

    [statusResponseMapping addAttributeMappingsFromDictionary:@{@"status":@"status"}]; 

RKResponseDescriptor *statusResponseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:statusResponseMapping method:RKRequestMethodPOST pathPattern:nil keyPath:@"response" statusCodes:statusCodes];

我从服务器收到正确的响应...但是只得到一个指针

 response.body={
      "response": {
        "status": "ok"
      }
    }
    2014-05-07 17:11:47.362 MyApp[145:60b] It Worked: {
        response = "<StatusResponse: 0x16ee2e10>";

    }

我缺少关键步骤或映射定义。我几乎达到了预期的结果。

在简单和复杂的情况下，我需要怎么做才能获得理想的结果？

使用以下新信息更新了我的问题

2014年5月8日更新，我将locationsMapping代码更改为...

RKObjectMapping *locationsMapping = [RKObjectMapping mappingForClass:[Locations class]];
    [locationsMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:@"locations" toKeyPath:@"locations" withMapping:locationMapping]];

这就使它更接近正确映射。结果是...

2014-05-08 13:28:17.795 MyApp[165:60b] It Worked: {
    locations =     (
        "<Locations: 0x14e69a10>",
        "<Locations: 0x14e695c0>"
    );

这几乎是正确的。我似乎缺少cityKey和StateKey的映射。我尚未定义Description方法。这是返回的原始JSON数据...

response.body={
  "locations": [
    {
      "distance": 0.6, 
      "major": 2, 
      "minor": 4 

    }, 
    {
      "distance": 1.0, 
      "major": 2, 
      "minor": 11 

    }
  ], 
  "cityKey": "11", 
  "stateKey": "21"
}

映射不返回cityKey和stateKey ...映射定义中仍然缺少某些内容吗？

更改位置后于2014年5月9日更新

RKObjectMapping *locationsMapping = [RKObjectMapping mappingForClass:[Locations class]];

    [locationsMapping addAttributeMappingsFromArray:@[
 @"cityKey",@"stateKey"]];

    [locationsMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:@"locations" toKeyPath:@"locations" withMapping:locationMapping]];


response.body={
  "locations": [
    {
      "distance": 0.6, 
      "major": 2, 
      "minor": 4
    }, 
    {
      "distance": 1.0, 
      "major": 2, 
      "minor": 11
    }
  ], 
  "cityKey": "10", 
  "stateKey": "15"
}
2014-05-09 13:18:17.669 MyApp[211:60b] It Worked: {
    locations  =     (
        "<Locations: 0x1780341e0>",
        "<Locations: 0x170027c40>"
    );
}

仍然缺少cityKey和stateKey ...不确定下一步该怎么做？

更新于2014年5月12日以回应响应者...

我有两个响应描述符。我错过了在原始说明中张贴一个。

RKResponseDescriptor *responseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:locationMapping method:RKRequestMethodAny pathPattern:nil keyPath:@"locations"  statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];
    RKResponseDescriptor *locationDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:locationsMapping method:RKRequestMethodAny pathPattern:@"/location" keyPath:nil statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];
    
    [[RKObjectManager sharedManager] addResponseDescriptor:responseDescriptor];
    [[RKObjectManager sharedManager] addResponseDescriptor:locationDescriptor];

我按建议更改了结构，但仍然缺少cityKey和stateKey ...我应该只使用一个响应描述符吗？

我找到了“使用多个ResponseDescriptor？”的答案。在本文中 http://www.softwarepassion.com/parsing-complex-json-with-objective-c-and-restkit/

当我回顾作者如何定义他的POJO时，我发现只需要一个ResponseDescriptor。其余的在关系的映射和定义中处理...

2014年5月15日更新

我测试了响应描述符。实际上只有一个人在努力产生“成功”结果。 locationDescriptor根本不起作用。单独使用时会产生错误。用作配对的一部分时被忽略。始终使用位置数据传递“工作正常”的描述符是带有keyPath的@@“locations”的responseDescriptor。

我读了 http://blog.mobilejazz.cat/ios-using-kvc-to-parse-json/

我有一个关于“...是您创建的自定义类的预期日志输出，但没有描述方法实现的问题”。描述方法的实现是什么意思？我需要添加什么才能将以下内容更改为映射结果的NSArray或NSDictionary？您能否根据以下位置分享一个示例？

2014-05-09 13:18:17.669 MyApp[211:60b] It Worked: {
        locations  =     (
            "<Locations: 0x1780341e0>",
            "<Locations: 0x170027c40>"
        );

2014年5月16日更新建议对类实现文件添加NSSTRING说明

response.body={
  "response": {
    "status": "ok"
  }
}
2014-05-16 10:32:26.260 MyApp[202:60b] It Worked: {
    response = "status: ok";
}

因此，我计算了NSString描述方法的实现情况并可以正常工作。

更新的第二部分是使用方法描述器，因为我可以看到我没有将映射的JSON替换为数据结构值，而我却获取了NULL

response.body={
  "locations": [
    {
      "distance": 0.0, 
      "major": 2, 
      "minor": 8, 

    }, 
    {
      "distance": 3.5, 
      "major": 2, 
      "minor": 9, 

    }, 
    {
      "distance": 2.6575364531836625, 
      "major": 2, 
      "minor": 10, 

    }
  ], 
  "cityKey": "10", 

  "stateKey": "21"
}
2014-05-16 09:48:08.328 MyApp[189:60b] It Worked: {
    locations =     (
        "location: (null) city: (null) state: (null)",
        "location: (null) city: (null) state: (null)",
        "location: (null) city: (null) state: (null)"
    );
}

第一个问题是我应该为字典数组中的三个位置以及一个cityKey和一个stateKey获得一个位置{distance，major，minor}。这是映射代码

RKObjectMapping* locationMapping = [RKObjectMapping mappingForClass:[Location class]];
    [locationMapping addAttributeMappingsFromDictionary:@{
                                                        @"distance": @"distance",
                                                        @"major": @"major",
                                                        @"minor": @"minor"
                                                        }];


    RKObjectMapping *locationsMapping = [RKObjectMapping mappingForClass:[Locations class]];

    [locationsMapping addAttributeMappingsFromArray:@[ @"cityKey",@"stateKey"]];



    [locationsMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:@"locations" toKeyPath:@"locations" withMapping:locationMapping]];

 //05/16/2014 this ResponseDesciptor is working
   RKResponseDescriptor *responseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:locationsMapping method:RKRequestMethodAny pathPattern:nil keyPath:@"locations" statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];

    [[RKObjectManager sharedManager] addResponseDescriptor:responseDescriptor];

为什么要为每个位置返回多个cityKey和stateKey？为什么当JSON数据返回时结果显示为null？

当keyPath设置为nil而不是@“locations”时，2014年5月19日更新异常

2014-05-19 10:53:53.902 MyApp[245:4907] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<Locations 0x17022d960> valueForUndefinedKey:]: this class is not key value coding-compliant for the key locations.'
*** First throw call stack:

代码提升IT RestKit代码行364

if ([self.dataSource respondsToSelector:@selector(mappingOperationShouldSetUnchangedValues:)] && [self.dataSource mappingOperationShouldSetUnchangedValues:self]) return YES;

    id currentValue = [self.destinationObject valueForKeyPath:keyPath];
    if (currentValue == [NSNull null]) {
        currentValue = nil;
    }

位置类头文件

#import <Foundation/Foundation.h>

@class Location;


@interface Locations : NSObject




@property (nonatomic, copy) Location *location;
@property (nonatomic, copy) NSString *cityKey;
@property (nonatomic, copy) NSString *stateKey;


@end

位置类实现文件

#import "Locations.h"

@implementation Locations

-(NSString *)description {

    return [NSString stringWithFormat:@"location: %@ cityKey: %@ stateKey: %@", self.location, self.cityKey, self.stateKey];
}

@end   

位置更改后的位置类属性

@property (nonatomic, copy) Location *location; 

至

@property (nonatomic, copy) NSMutableArray *locations;

keyPath为nil时收到期望的结果

response.body={
  "locations": [
    {
      "distance": 0.0, 
      "major": 2, 
      "minor": 8 

    }, 
    {
      "distance": 3.5, 
      "major": 2, 
      "minor": 9 

    }, 
    {
      "distance": 2.6575364531836625, 
      "major": 2, 
      "minor": 10 

    }
  ], 
  "cityKey": "1", 

  "stateKey": "1"
}
2014-05-19 14:19:45.040 MyApp[290:60b] It Worked: {
    "<null>" = "location: (\n    \"distance: 0 major: 2  minor: 8 \",\n    \"distance: 3.5 major: 2  minor: 9 \",\n    \"distance: 2.657536453183662 major: 2  minor: 10 \"\n) cityKey: 1 stateKey: 1";
}

哪个解决了这个问题。

Answer 1

创建locationsMapping时，应使用@"locations"将locationMapping作为关系添加(而不是直接作为属性)。

您应该有一个使用locationsMapping的响应描述符。

这个:

2014-05-07 17:11:47.362 MyApp[145:60b] It Worked: {
    response = "<StatusResponse: 0x16ee2e10>";
}

是您创建的自定义类的预期日志输出，但该类没有 description方法实现。

RKObjectMapping *locationsMapping = [RKObjectMapping mappingForClass:[Locations class]];
[locationsMapping addAttributeMappingsFromArray:@[@"cityKey", @"stateKey"]];
[locationsMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:@"locations" toKeyPath:@"locations" withMapping:locationMapping]];

在 Locations类上添加:

- (NSString *)description
{
    return [NSString stringWithFormat:@"city:%@ state:%@ locations:%@", self.cityKey, self.stateKey, self.locations];
}

和 Location类的类似方法。