RestKit 没有从 JSON 映射图像

Posted 2023-03-16

【中文标题】RestKit 没有从 JSON 映射图像

【英文标题】：RestKit not mapping Images from JSON

【发布时间】：2013-05-10 16:59:39

【问题描述】：

我无法正确映射 JSON 响应中的图像，我不知道为什么。

这是错误：“W restkit.object_mapping:RKObjectMappingOperation.m:244 keyPath 'images' 处的值转换失败。没有从 '__NSArrayM' 转换为 'Images' 的策略”

这里是 JSON：

    "timestamp": "2013-05-10T03:09:39Z",
    "feed": [
        "headline": "Head text",
        "links": 
            "api": 
                "news": 
                    "href": "http://api.website.com/v1/91"
                ,
                "self": 
                    "href": "http://api.website.com/v1/91"
                
            ,
            "web": 
                "href": "http://website.com/the/story"
            ,
            "mobile": 
                "href": "http://m.website.com/wireless/story?storyId=9254113"
            
        ,
        "source": "Associated Press",
        "description": "Description text.",
        "images": [
            "height": 324,
            "alt": "",
            "width": 576,
            "name": "Name text",
            "caption": "Caption text.",
            "url": "http://a.website.com/media/2013/0508.jpg"
        ],

Feed.h

@property (nonatomic, strong) Links *links;
@property (nonatomic, strong) Images *images;
@property (nonatomic, strong) Video *video;
@property (nonatomic, strong) NSString *headline;
@property (nonatomic, strong) NSString *source;
@property (nonatomic, strong) NSDate *published;
@property (nonatomic, strong) NSString *description;
@property (nonatomic, strong) NSString *premium;

+ (RKObjectMapping *) mapping;

Feed.m

+ (RKObjectMapping *)mapping 
    RKObjectMapping *objectMapping = [RKObjectMapping mappingForClass:[self class] usingBlock:^(RKObjectMapping *mapping) 
        [mapping mapKeyPathsToAttributes:
         @"headline", @"headline",
         @"source", @"source",
         @"published", @"published",
         @"description", @"description",
         @"premium", @"premium",
         nil];
        [mapping hasOne:@"links" withMapping:[Links mapping]];
        [mapping hasOne:@"images" withMapping:[Images mapping]];
        //[mapping hasMany:@"images" withMapping:[Images mapping]];
        [mapping hasOne:@"video" withMapping:[Video mapping]];
    ];

    return objectMapping;

图片.h

@property (nonatomic, strong) NSNumber *height;
@property (nonatomic, strong) NSNumber *width;
@property (nonatomic, strong) NSString *caption;
@property (nonatomic, strong) NSURL *url;

+ (RKObjectMapping *) mapping;

图片.m

+ (RKObjectMapping *)mapping 
    RKObjectMapping *objectMapping = [RKObjectMapping mappingForClass:[self class] usingBlock:^(RKObjectMapping *mapping) 
        [mapping mapKeyPathsToAttributes:
         @"height", @"height",
         @"width", @"width",
         @"caption", @"caption",
         @"url", @"url",
         nil];
    ];

    return objectMapping;

除图像外，其他一切都正确映射。我不知道它是否与它是一个数组有关，但它只有一个结果，所以它不一定是一个数组？如果不是，那我该怎么写……我只是不完全清楚为什么它不映射。

如您所见，我尝试了 hasMany: 和 hasOne: 映射，但都没有成功，我得到了同样的错误。

我尝试使用 NSLog(@"url image: %@", feedLocal.images.url);' but get(null). Even though I thought it would work becauseNSLog(@"href web: %@", feedLocal.links.web.href);` 非常适合我的链接 href。

任何帮助将不胜感激，非常感谢！

【问题讨论】：

Restkit 无法理解数组 - 使用可转换的！

@BharatGulati 感谢您的回复！我不确定这到底是什么意思，你能给我一个sn-p代码吗？

【参考方案1】：

在 Feed.h 中，您需要将 images 属性更改为：

@property (nonatomic, strong) NSArray *images;

您应该将映射设置为hasMany:。

【讨论】：

感谢您的回复！当我根据您的建议更改代码时，我收到一条错误消息，提示 property url not found on object of type NSArray，我应该进行哪些其他调整？

[mapping hasMany:@"images" withMapping:[Images mapping]]; 是我将映射更改为

奇怪...尝试跟踪日志记录 RKLogConfigureByName("RestKit/ObjectMapping", RKLogLevelTrace);

这是一个巧妙的提示。不过，我应该在这里寻找什么？

如果我知道它会说什么，我不会对上述更改为什么不起作用感到困惑 :-) 与映射“图像”或“图像”有关。只是有关它在记录错误之前所做的事情的更多信息。