ios - 如何在 Obj-C 中解析 JSON

Question

我是 JSON 新手，并试图理解该结构，以便解析来自 Web 服务的一些数据。

作为模型，我使用应用程序 tutorial 中的代码显示来自 Kiva 的贷款。示例应用程序中的代码能够从以下 json 输出中显示 kiva 贷款(我已经剪掉了很多内容，因为它显示了很长的列表):

{"paging":{"page":1,"total":6446,"page_size":20,"pages":323},"loans":[{"id":910788,"name":"Harriet","description":{"languages":["en"]},"status":"fundraising","funded_amount":0,"basket_amount":0,"image":{"id":1918586,"template_id":1},"activity":"Poultry","sector":"Agriculture","themes":["Vulnerable Groups","Youth"],"use":"to buy birds, feed, and vaccines.","location":{"country_code":"UG","country":"Uganda","town":"Zanna","geo":{"level":"town","pairs":"2 33","type":"point"}},"partner_id":65,"posted_date":"2015-07-03T15:30:02Z","planned_expiration_date":"2015-08-02T15:30:02Z","loan_amount":250,"borrower_count":1,"lender_count":0,"bonus_credit_eligibility":true,"tags":[]}]}

我的 json 输出如下所示:

{"tasks":[{"row":{"userid":"1","task":"send email to Bob","longtask":"include attached memo"}}]}

我如何修改下面的 Objective-c 来使用具有该结构的 json。

注意:我的 json 基本上具有三个级别:对象“任务”、行和字段值，如任务:发送电子邮件中所示。

kiva feed 似乎在开头有一个分页的东西(这有点令人困惑)，然后是对象“贷款”，没有行级别，然后是名称中的字段值:harriet。

kiva 代码有多个字段，如下所示。对于我的项目，我只想显示几个字段，如 task 和 longtask。

应用教程中的代码:

 NSArray* latestLoans = [json objectForKey:@"loans"]; //2
    // 1) Get the latest loan
    NSDictionary* loan = [latestLoans objectAtIndex:0];

    // 2) Get the funded amount
    NSNumber* fundedAmount = [loan objectForKey:@"funded_amount"];

    // 3) Set the label appropriately
    humanReadble.text = [NSString stringWithFormat:@"Latest loan: %@ from %@ has raised $%.2f to pursue their entrepreneural dream",
                         [loan objectForKey:@"name"],
                         [(NSDictionary*)[loan objectForKey:@"location"] objectForKey:@"country"],
                         fundedAmount
                         ];

    //build an info object and convert to json
    NSDictionary* info = [NSDictionary dictionaryWithObjectsAndKeys:
                          [loan objectForKey:@"name"], @"who",
                          [(NSDictionary*)[loan objectForKey:@"location"] objectForKey:@"country"], @"where",
                          [NSNumber numberWithFloat: fundedAmount], @"what",
                          nil];

Answer 1

我用代码解析了你的输出 JSON:

NSString *filePath = [[NSBundle mainBundle] pathForResource:@"nameofilejson" ofType:@".json"];
NSData *data = [NSData dataWithContentsOfFile:filePath];
NSDictionary *json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];
NSLog(@"%@",json); 
NSMutableArray *getElement = [json objectForKey:@"tasks"];
for (NSDictionary *dict in getElement) {
    NSArray *array = [dict objectForKey:@"row"];
    NSString *str = [array objectAtIndex:0];
}