使用 Restkit 0.20 映射此类与键的键值编码不兼容

Posted 2023-03-05

【中文标题】使用 Restkit 0.20 映射此类与键的键值编码不兼容

【英文标题】：Mapping with Restkit 0.20 this class is not key value coding-compliant for the key

【发布时间】：2013-09-30 21:44:53

【问题描述】：

您好，我在使用 restkit 从 api 映射数据时遇到问题。我有以下数据。我非常感谢任何能指出我的错误的人。

"GameId":1,"Items":

["Id":1,"PicUrl":"someurlhere","Answers":

["Paris","New York","San Francisco","Rome"],"CorrectAnswer":"San Francisco","Categories"]

这就是我计划在客户端存储数据的方式：

#import <Foundation/Foundation.h>

GameObjects.h

    @interface GameObjects : NSObject
    @property(nonatomic, strong)NSNumber *GameId;
    @property(nonatomic,strong)NSMutableArray *Items;
    @property(nonatomic,strong)NSNumber *IId;
    @property(nonatomic,strong)NSURL *PicUrl;
    @property(nonatomic,strong)NSMutableArray *Answers;
    @property(nonatomic,strong)NSString *CorrectAnswer;
    @property(nonatomic,strong)NSString *CategoryName;
    @end



GameObjects.m

#import "GameObjects.h"

@implementation GameObjects
@synthesize GameId;
@synthesize Items;
@synthesize Answers;
@synthesize IId;
@synthesize CategoryName;
@synthesize CorrectAnswer;
@synthesize PicUrl;
- (id)init

    self = [super init];
    if (self) 

        Items = [[NSMutableArray alloc]initWithObjects:PicUrl,Answers,CorrectAnswer,CategoryName, nil];

    
    return self;


@end

这就是我进行映射的方式：

-(void)viewDidLoad


    //restkit
    RKObjectMapping *GameMapping = [RKObjectMapping mappingForClass:[GameObjects class]];

    [GameMapping addAttributeMappingsFromDictionary:@   @"GameId":@"GameId",
                                                         @"Items": @"Items",
                                                         @"Id": @"Id",
                                                         @"PicUrl": @"PicUrl",
                                                         @"Answers":@"Answers",
                                                         @"CorrectAnswer":@"CorrectAnswer",
                                                         @"CategoryName":@"CategoryName"
                                                         ];

    RKResponseDescriptor *responseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:GameMapping method:RKRequestMethodGET pathPattern:nil keyPath:@"GameId" statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];
    NSURL *URL = [NSURL URLWithString:@"someurlhere"];
    NSURLRequest *request =[NSURLRequest requestWithURL:URL];
    RKObjectRequestOperation *objectRequestOperation = [[RKObjectRequestOperation alloc]initWithRequest:request responseDescriptors:@[responseDescriptor]];
    [objectRequestOperation setCompletionBlockWithSuccess:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) 
        RKLogInfo(@"Load collection of Articles: %@", mappingResult.array);
     failure:^(RKObjectRequestOperation *operation, NSError *error) 
        RKLogError(@"Operation failed with error: %@", error);
    ];
    [objectRequestOperation start];

我的输出：

2013-09-30 14:28:04.204 FlickRest[3826:a0b] I restkit:RKLog.m:34 RestKit logging initialized...
2013-09-30 14:28:04.478 FlickRest[3826:a0b] ViewController - viewDidLoad
2013-09-30 14:28:12.158 FlickRest[3826:a0b] I restkit.network:RKObjectRequestOperation.m:180 GET 'someurlhere'

2013-09-30 14:28:18.243 FlickRest[3826:1a07] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<__NSCFNumber 0x8e20580> valueForUndefinedKey:]: this class is not key value coding-compliant for the key GameId.'
*** First throw call stack:
(
    0   CoreFoundation                      0x020ca5e4 __exceptionPreprocess + 180
    1   libobjc.A.dylib                     0x01e4d8b6 objc_exception_throw + 44
    2   CoreFoundation                      0x0215a6a1 -[NSException raise] + 17
    3   Foundation                          0x00c95b0a -[NSObject(NSKeyValueCoding) valueForUndefinedKey:] + 282
    4   Foundation                          0x00c02b61 _NSGetUsingKeyValueGetter + 81
    5   Foundation                          0x00c0219b -[NSObject(NSKeyValueCoding) valueForKey:] + 260
    6   Foundation                          0x00c21c9a -[NSObject(NSKeyValueCoding) valueForKeyPath:] + 409
    7   FlickRest                           0x0007fc31 -[RKMappingSourceObject valueForKeyPath:] + 833
    8   FlickRest                           0x00085247 -[RKMappingOperation applyAttributeMappings:] + 1671
    9   FlickRest                           0x0008cc3e -[RKMappingOperation main] + 4062
    10  Foundation                          0x00ca9a69 -[__NSOperationInternal _start:] + 671
    11  Foundation                          0x00c26798 -[NSOperation start] + 83
    12  FlickRest                           0x0007a2c5 -[RKMapperOperation mapRepresentation:toObject:atKeyPath:usingMapping:metadata:] + 1957
    13  FlickRest                           0x00078b40 -[RKMapperOperation mapRepresentation:atKeyPath:usingMapping:] + 1904
    14  FlickRest                           0x0007b4bd -[RKMapperOperation mapRepresentationOrRepresentations:atKeyPath:usingMapping:] + 829
    15  FlickRest                           0x0007be12 -[RKMapperOperation mapSourceRepresentationWithMappingsDictionary:] + 2210
    16  FlickRest                           0x0007c7db -[RKMapperOperation main] + 1403
    17  Foundation                          0x00ca9a69 -[__NSOperationInternal _start:] + 671
    18  Foundation                          0x00c26798 -[NSOperation start] + 83
    19  FlickRest                           0x000ccb7a -[RKObjectResponseMapperOperation performMappingWithObject:error:] + 1354
    20  FlickRest                           0x000cabb3 -[RKResponseMapperOperation main] + 2371
    21  Foundation                          0x00ca9a69 -[__NSOperationInternal _start:] + 671
    22  Foundation                          0x00c26798 -[NSOperation start] + 83
    23  Foundation                          0x00cabd34 __NSOQSchedule_f + 62
    24  libdispatch.dylib                   0x028de4b0 _dispatch_client_callout + 14
    25  libdispatch.dylib                   0x028cc088 _dispatch_queue_drain + 450
    26  libdispatch.dylib                   0x028cbe85 _dispatch_queue_invoke + 126
    27  libdispatch.dylib                   0x028cce25 _dispatch_root_queue_drain + 83
    28  libdispatch.dylib                   0x028cd13d _dispatch_worker_thread2 + 39
    29  libsystem_c.dylib                   0x02bf6e72 _pthread_wqthread + 441
    30  libsystem_c.dylib                   0x02bdedaa start_wqthread + 30
)
libc++abi.dylib: terminating with uncaught exception of type NSException

【参考方案1】：

您已经设置了响应描述符keyPath:@"GameId"，但它应该是keyPath:nil。通过将其设置为 @"GameId"，RestKit 将导航到 JSON 并尝试将所有映射内容应用到为 GameId 键设置的 NSNumber 值。

【参考方案2】：

'this class is not key value coding-compliant for the key' 这个错误通常发生在映射中定义的key-value关系在某种程度上与JSON key-value不匹配时。在您的情况下，将 keyPath 设置为“GameId”意味着您的 JSON 必须将根键作为“GameId”，但事实并非如此并导致崩溃。