将 json 数据解析到 iphone [英] parsing json feeds into iphone

问题描述

我试图将公共 json flickr 提要解析到 iphone.我遇到错误..

-JSONValue 失败.错误跟踪是:("错误域=org.brautaset.JSON.ErrorDomain Code=3 \"无法识别的前导字符\" UserInfo=0x4b43100 {NSLocalizedDescription=无法识别的前导字符}").....

以下是 json 提要:

如果您使用来自上述 http://jsonlint.com 中的 URL 的响应，它会告诉您它是有效的 JSON.

nojsoncallback 记录在 http://www.flickr.com/services/api/response.json.html

---

如何阅读该回复的快速示例.JSON 字符串的顶层元素是一个对象，通常由 JSON 解析器映射到字典:

//从 Flickr API 获取 JSON 字符串NSString *jsonString = ...;//将 JSON 字符串解析为字典//(在本例中，通过 SBJSON)NSDictionary *responseObject = [jsonString JSONValue];//字典有一个条目叫做items"，它是一个数组NSArray *items = [responseObject objectForKey:@"items"];//迭代项目.每个项目都是一个对象，因此是一个字典for (NSDictionary *item in items) {//每个条目字典都有一个名为author_id"的条目，它是一个字符串NSString *authorId = [item objectForKey:@"author_id"];//记录作者idNSLog(@"author_id = %@", authorId);}

i was trying to parse public json flickr feed into iphone.i m getting an error..

-JSONValue failed. Error trace is: (
    "Error Domain=org.brautaset.JSON.ErrorDomain Code=3 \"Unrecognised leading character\" UserInfo=0x4b43100 {NSLocalizedDescription=Unrecognised leading character}"
).....

below is the json feed:

http://api.flickr.com/services/feeds/photos_public.gne?tags=hackdayindia&lang=en-us&format=json.....

i d be so greatful if you guys could help me out

解决方案

Your response data is not valid JSON because of the jsonFlickrFeed( … ) callback returned by the Flickr API. In order to obtain valid JSON, add nojsoncallback=1 to your query. Using your example, the corresponding URL is:

http://api.flickr.com/services/feeds/photos_public.gne?tags=hackdayindia&lang=en-us&format=json&nojsoncallback=1

If you use the response from the URL above in http://jsonlint.com, it’ll tell you it’s valid JSON.

nojsoncallback is documented in http://www.flickr.com/services/api/response.json.html

---

A quick example of how to read that response. The top level element of the JSON string is an object, which is usually mapped to a dictionary by JSON parsers:

// Obtain the JSON string from Flickr API
NSString *jsonString = …;

// Parse the JSON string into a dictionary
// (in this example, via SBJSON)
NSDictionary *responseObject = [jsonString JSONValue];

// The dictionary has an entry called "items", which is an array
NSArray *items = [responseObject objectForKey:@"items"];

// Iterate over the items. Each item is an object, hence a dictionary
for (NSDictionary *item in items) {
    // Each item dictionary has an entry called "author_id", which is a string
    NSString *authorId = [item objectForKey:@"author_id"];

    // Log the author id
    NSLog(@"author_id = %@", authorId);
}

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