披风：解析JSON时捕获到的异常'NSInvalidArgumentException'

Question

I am using the Mantle framework, and I seem to be having some problems with serializing some values into a MTLModel . This is the JSON I am receiving from the server:

{
    "id":50,
    "name":"UserName",
    "email":"user@username.com",
    "profile":{
        "picture": {
            "original": "http://original.com/picture",
            "versions": {
                "thumb": "http://thumb.com/picture",
                "small": "http://small.com/picture"
            }
        }
    }
}

I've setup my MTLModel s in the following manner:

User

@interface User : MTLModel <MTLJSONSerializing>

@property (nonatomic, readonly) NSNumber *id;
@property (nonatomic) NSString *name;
@property (nonatomic) NSString *email;
@property (nonatomic) Profile *profile;

@end

@implementation User

+ (NSDictionary *)JSONKeyPathsByPropertyKey {
    return @{
            @"id": @"id",
            @"name": @"name",
            @"email": @"email",
            @"profile": @"profile"
            };
}

- (NSValueTransformer *)profileJSONTransformer {
    return [MTLValueTransformer reversibleTransformerWithForwardBlock:^(NSDictionary *profileDict) {
        return [MTLJSONAdapter  modelOfClass:Profile.class
                            fromJSONDictionary:profileDict
                            error:nil];
    } reverseBlock:^(Profile *profile) {
        return [MTLJSONAdapter JSONDictionaryFromModel:profile];
   }];
}

@end

Profile

@interface Profile : MTLModel <MTLJSONSerializing>

@property (nonatomic) Picture *picture;

@end

@implementation Profile

+ (NSDictionary *)JSONKeyPathsByPropertyKeys {
    return @{
            @"picture": @"picture"
           };
}

- (NSValueTransformer *)pictureJSONTransformer {
    return [MTLValueTransformer reversibleTransformerWithForwardBlock:^(NSDictionary *picDict) {
        return [MTLJSONAdapter  modelOfClass:Picture.class
                            fromJSONDictionary:picDict
                            error:nil];
    } reverseBlock:^(Picture *picture) {
        return [MTLJSONAdapter JSONDictionaryFromModel:picture];
    }];
}

@end

Picture

@interface Picture : MTLModel <MTLJSONSerializing>

@property (nonatomic) NSString *original;
@property (nonatomic) Versions *versions;

@end

@implementation Picture

+ (NSDictionary *)JSONKeyPathsByPropertyKeys {
    return @{
            @"original": @"original",
            @"versions": @"versions"
           };
}

- (NSValueTransformer *)versionsJSONTransformer {
    return [MTLValueTransformer reversibleTransformerWithForwardBlock:^(NSDictionary *versionDict) {
        return [MTLJSONAdapter  modelOfClass:Versions.class
                            fromJSONDictionary:versionDict
                            error:nil];
    } reverseBlock:^(Versions *versions) {
        return [MTLJSONAdapter JSONDictionaryFromModel:versions];
    }];
}

@end

Versions

@interface Versions : MTLModel <MTLJSONSerializing>

@property (nonatomic) NSString *thumb;
@property (nonatomic) NSString *small;

@end

@implementation Versions

+ (NSDictionary *)JSONKeyPathsByPropertyKey {
    return @{
             @"thumb": @"thumb",
             @"small": @"small"
             };
}

@end

I am doing the following Overcoat POST call to grab the JSON. I am receiving the JSON fine when I NSLog the response:

[[Client getInstance] POST:@"authorize.json" parameters:params completion:^(id response, NSError *error) {
    if (!error) {
        User *user = [MTLJSONAdapter modelOfClass:[User class] fromJSONDictionary:[response result] error:nil];
        Picture *picture = [[user profile] picture];
        NSLog(@"%@", picture);
    } else {
        NSLog(@"%@", error);
    }
}];

The problem occurs when I try to grab the Picture object like so:

Picture *picture = [[user profile] picture];

I get an exception of:

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFDictionary picture]: unrecognized selector sent to instance 0x7f95026d4210'

How can I fix this? What am I doing wrong?

Answer 1

you are not parsing your json properly.the picture dictionary is nested inside profile. get it like something

Nsmutabledictinary *profile=[jsondic objectforkey:@"Profile"];

Nsmutabledictinary *picture=[profile objectforkey:@"Picture"];

please correct the syntax errors as i didnt write the code in editor so there can be syntax error in the code .thanks