如何在 dart/flutter 中提取 JSON 子数据

Posted 2023-02-23

【中文标题】如何在 dart/flutter 中提取 JSON 子数据

【英文标题】：How to extract JSON child data in dart / flutter

【发布时间】：2019-12-30 13:33:43

【问题描述】：

我想提取 queryResult 的子值，即。 “你好。我是聊天机器人所以我们开始吧？”从 JSON 使用颤振

最终responseJson = json.decode(response.body);

print("DATA \n $responseJson['queryResult']");

JSON 数据 ===>

  
   "responseId":"123456789",
   "queryResult":  
      "queryText":"Hello",
      "action":"input.welcome",
      "parameters":  

      ,
      "allRequiredParamsPresent":true,
      "fulfillmentText":"Greetings! How can I assist?",
      "fulfillmentMessages":[  
           
            "text":  
               "text":[  
                  "Hello there. I am chat bot So shall we get started?"
               ]
            
         ,
           
            "quickReplies":  
               "quickReplies":[  
                  "Yes",
                  "No"
               ]
            
         
      ],
      "outputContexts":[  
           
            "name":"xyz",
            "lifespanCount":5
         
      ],
      "intent":  
         "name":"xyz",
         "displayName":"Default Welcome Intent"
      ,
      "intentDetectionConfidence":1,
      "diagnosticInfo":  
         "webhook_latency_ms":5
      ,
      "languageCode":"en"
   ,
   "webhookStatus":  
      "message":"Webhook execution successful"
   

我无法读取 queryResult 的子数据使用

final responseJson = json.decode(response.body);
print("DATA \n $responseJson['queryResult']");

【问题讨论】：

您需要使用模式序列化您的 json 数据。这是链接flutter.dev/docs/development/data-and-backend/json

【参考方案1】：

如果您想获得该特定行，则可以通过这种方式获得，但为了获得更多用途，最好像这里一样序列化 json：https://flutter.dev/docs/development/data-and-backend/json

print("DATA \n $responseJson['queryResult']['fulfillmentMessages'][0]['text']['text'][0]");

为了更容易理解路径：

print("DATA \n $
      responseJson['queryResult']
        ['fulfillmentMessages'][0]
          ['text']
            ['text'][0]
      "
 );

整个代码和你的一样：

import 'dart:convert';

final responseBody = '"responseId":"123456789","queryResult":"queryText":"Hello","action":"input.welcome","parameters":,"allRequiredParamsPresent":true,"fulfillmentText":"Greetings! How can I assist?","fulfillmentMessages":["text":"text":["Hello there. I am chat bot So shall we get started?"],"quickReplies":"quickReplies":["Yes","No"]],"outputContexts":["name":"xyz","lifespanCount":5],"intent":"name":"xyz","displayName":"Default Welcome Intent","intentDetectionConfidence":1,"diagnosticInfo":"webhook_latency_ms":5,"languageCode":"en","webhookStatus":"message":"Webhook execution successful"';

void main() 
  final Map<String, dynamic> responseJson = json.decode(responseBody);

  print("DATA \n $
      responseJson['queryResult']
        ['fulfillmentMessages'][0]
          ['text']
            ['text'][0]
      "
 );