访问从NSJSONSerialization生成的NSDictionary中的JSON数据 [英] Accessing JSON data inside an NSDictionary generated from NSJSONSerialization

问题描述

在访问以下网址中的JSON数据时遇到一些问题（ http://jamesstenson.com/portraits /？json = 1 ），基本上我想访问附件下面的完整网址。我的代码目前如下：

Having some trouble accessing the JSON data in the following URL ( http://jamesstenson.com/portraits/?json=1 ), basically I want to access the "full" "url"'s underneath "attachments". My code at the moment is as follows:

NSError *e = nil;
NSData *jsonFeed = [NSData dataWithContentsOfURL:[NSURL URLWithString:@"http://jamesstenson.com/portraits/?json=1"]]; 
NSDictionary *jsonData = [NSJSONSerialization JSONObjectWithData:jsonFeed options:NSJSONReadingMutableContainers error: &e];

if (!jsonData) {
    NSLog(@"Error parsing JSON: %@", e);
} else {

    for(NSDictionary *item in [jsonData objectForKey:@"page"]) {
        for(NSDictionary *attachment in [item objectForKey:@"images"]) {
            NSLog(@"%@", attachment);
        }
    }
}

这不断引发错误：

2011-12-21 10:13:39.362 JSON[3463:f803] -[__NSCFString objectForKey:]: unrecognized selector sent to instance 0x6a7b500

2011-12-21 10：13：39.363 JSON [3463：f803] * 由于未捕获的异常'NSInvalidArgumentException'而终止应用程序，原因：' - [__ NSCFString objectForKey：]：无法识别的选择器发送到实例0x6a7b500'

2011-12-21 10:13:39.363 JSON[3463:f803] * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFString objectForKey:]: unrecognized selector sent to instance 0x6a7b500'

I我知道我错误地访问了这些项目，但无法弄清楚如何实现这一目标。我尝试了几种解决方案，例如 http://blogs.captechconsulting .com / blog / nathan-jones / getting-started-json-ios5 - 但没有运气。我是iOS开发的新手，对JSON有一点了解。感谢大家提前帮助。

I am aware I am accessing the items wrongly, but cannot figure out how to achieve this. I've tried several solutions such as http://blogs.captechconsulting.com/blog/nathan-jones/getting-started-json-ios5 - but no luck. I am complete newbie to iOS development and have a little knowledge of JSON. Thanks for everyones help in advance.

推荐答案

问题在于你的循环

for(NSDictionary *item in [jsonData objectForKey:@"page"]) 

你不会在item中获得NSDictionary，它会返回Dictionary的键，这将是NSString

You won't get NSDictionary in item, it will return you key of Dictionary, which would be NSString

检查此链接对于目标c中的每个循环，用于访问NSMutable词典知道如何遍历NSDictionay

Check this link for each loop in objective c for accessing NSMutable dictionary to know how to traverse through NSDictionay

以下是根据您的要求修改的代码，可能对您有帮助

Below is the modified code for your requirement, might help you

if (!jsonData) {
        NSLog(@"Error parsing JSON: %@", e); } else {
        NSArray *attachments = [[jsonData objectForKey:@"page"] objectForKey:@"attachments"];
        for(NSDictionary *object in attachments) {
              NSLog(@"%@", [object objectForKey:@"images"]);
              NSLog(@"%@", [[[object objectForKey:@"images"] objectForKey:@"full"] objectForKey:@"url"]);
        } 
}

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