Issue parsing an Array of JSON objects Error: Invalid conversion from runtime type List<ANY> to Map<String,ANY>

Question

I am running into an issue getting values from my json payload.

The schema is as follows:

{
  "thank_you_message": "Спасибо, что нашли время на прохождение нашего опроса. Ваше мнение очень важно для нас.",
  "Survey_Choices__c": [
    {
      "attributes": {
        "type": "ВыборВопросаОпроса",
        "url": "/services/data/v49.0/sobjects/SurveyQuestionChoice/0Kct0000000KzFyCAK"
      },
      "Name": "Интернет",
      "SurveyVersionId": "0Kst0000000KyjzCAC",
      "DeveloperName": "c_0dc4ff3e_13c5_46dd_b3e7_b5e9d2af8679",
      "Id": "0Kct0000000KzFyCAK"
    },
    {
      "attributes": {
        "type": "ВыборВопросаОпроса",
        "url": "/services/data/v49.0/sobjects/SurveyQuestionChoice/0Kct0000000KzFzCAK"
      },
      "Name": "мыПереводим",
      "SurveyVersionId": "0Kst0000000KyjzCAC",
      "DeveloperName": "c_296e4586_c4c3_43aa_8b55_4bb2f643befd",
      "Id": "0Kct0000000KzFzCAK"
    }]
}

I need to loop through all Survey_Choices__c but am running into problems.

My attempted steps

1. Deserialize the json payload:

Map<String, Object> surveyMap = (Map<String, Object>) JSON.deserializeUntyped(output);

2. Get the survey choice objects (I wanted to set this up as a Map<String,Object>, but I get a conversion error must be List<Object>)

3. Use the following code to loop through each key-value pair

 List<Object> surveyChoices = (List<Object>) surveyMap.get('Survey_Choices__c');
    Map<String, Object> test = new Map<String, Object>();
      for (Object s : surveyChoices) {
         test.putAll((Map<String, Object>) s);
       }
    System.debug(test);

The above code only prints out one json object in the array.

My question is how can I loop through the array of JSON objects and get the name value of each object.

Answer 1

Firstly, it is list of objects in Survey_Choices__c and each object has key-value pair which is how you need to cast and create object. By creating just Map<String, Object>, you are replacing the previous object (Map<String, Object>) in every iteration and so you are seeing just 1 object.

You can iterate as below:

Map<String, Object> surveyMap = (Map<String, Object>) JSON.deserializeUntyped(output);
List<Object> surveyChoices = (List<Object>) surveyMap.get('Survey_Choices__c');
List<Map<String, Object>> test = new List<Map<String, Object>>();
for (Object s : surveyChoices) {
    test.add((Map<String, Object>) s);
}
System.debug(test);

for(Map<String, Object> item : test) {
    for(String key : item.keySet()) {
        System.debug(key + '__' + item.get(key));
    }
}