xcode和从NSDictionary提取数据值（objectForKey和valueForKey）

我对数据类型NSDictionary有点困惑，因为它属于JSON结构，需要帮助。以下是我的JSON输出：

{
    "requestDetails":
    {
        "timeStamp":"2001-12-17T09:30:47-08:00",
        "transactionType":"QUERY",
        "action":"GET INVOICES",
    },
    "Payload":
    {
        "event":
        {
            "sourceRecordType":"INVOICE INQUIRY",
            "serviceRecordType":"INVOICE",
            "ownershipType":"EXPLICIT",
        },
    },
    "executionDetails":
    {
        "timeStamp":"2012-12-04T13:48:21-08:00",
        "statusType":   "SUCCESSFUL_TRANSACTION",
        "statusCode":"0",
        "DBRecordCount":"0",
        "processedRecordCount":"0",
        "warning":
        [
            {
                "errorCode":"257",
                "errorDescription":"Criteria specified is incorrect. Please Verify that the criteria is correct.",
                "__hashCodeCalc":false
            },
            {   "errorCode":"60",
                "errorDescription":"No results were found.  Please enter new search criteria.",
                "__hashCodeCalc":false
            }
        ],
    },
}

现在我的理解是，整个过程都是字典和objectForKey:@“executionDetails”将给出以下输出：

{
        "timeStamp":"2012-12-04T13:48:21-08:00",
        "statusType":   "SUCCESSFUL_TRANSACTION",
        "statusCode":"0",
        "DBRecordCount":"0",
        "processedRecordCount":"0",
        "warning":
        [
            {
                "errorCode":"257",
                "errorDescription":"Criteria specified is incorrect. Please Verify that the criteria is correct.",
                "__hashCodeCalc":false
            },
            {   "errorCode":"60",
                "errorDescription":"No results were found.  Please enter new search criteria.",
                "__hashCodeCalc":false
            }
        ],
    }

如何选取[]括号内的值。我试过valueForKey和ObjectForKey。我不清楚处理结构，非常感谢您的帮助

warning":
        [
            {
                "errorCode":"257",
                "errorDescription":"Criteria specified is incorrect. Please Verify that the criteria is correct.",
                "__hashCodeCalc":false
            },
            {   "errorCode":"60",
                "errorDescription":"No results were found.  Please enter new search criteria.",
                "__hashCodeCalc":false
            }
        ],

---

谢谢

这只是一个数组。您可以像这样访问它的内容

NSDictionary *executionDetails = [json objectForKey:@"executionDetails"];
NSArray *warnings = [executionDetails objectForKey:@"warning"];

for (NSDictionary *warning in warnings) {
    NSLog(@"%@", warning);
}
// To access an individual warning use: [warnings objectAtIndex:0]

您还可以使用现代Objective-C语法使其更清晰：

NSDictionary *executionDetails = json[@"executionDetails"];
NSArray *warnings = executionDetails[@"warning"];
NSLog(warnings[0]);

---

谢谢它工作得很好。但是，有没有一个地方可以让我去寻求帮助，以了解objectForKey和JSON输出是如何映射的呢？在这种情况下，您并不是真正在使用JSON。JSON已经反序列化，您正在使用或。否则，我建议您参考您正在使用的JSON库的文档，例如，谢谢。知道了。我将参考JSON库。