在 flutter 中解码字符串 json 时出错，“字符串类型不是 Map 类型的子类型”

Question

again with some doubts in flutter, I need to decode a json that I receive from an api, but it gives me a conversion error, it is because the json comes as a deserialized string, some way to solve this detail. Thank you very much for the help.

String strVar = "{ \"status\": \"1\", \"message\": \"test\",
                    \"cars\": [ { \"carId\": \"1\", \"carName\": \"Car N°1\" }, 
                                    { \"carId\": \"2\", \"carName\": \"Car N°1\" }, 
                                    { \"businessId\": \"3\", \"carName\": \"Car N°1\" }
                                   ] }"

//Here error
Map<String,dynamic> mapAPI = json.decode(strVar);

Answer 1

To use multi-line string literals, encase the string in triple quotations ''' , or use only one line.

Single-line

String strVar = "{ \"status\": \"1\", \"message\": \"test\",\"cars\": [ { \"carId\":\"1\", \"carName\": \"Car N°1\" }, { \"carId\": \"2\", \"carName\": \"Car N°1\" }, { \"businessId\": \"3\", \"carName\": \"Car N°1\" }] }";
  
Map<String, dynamic> map = jsonDecode(strVar);
  
print(map);

Multi-line

String strVar = '''{ \"status\": \"1\", \"message\": \"test\",
                    \"cars\": [ { \"carId\": \"1\", \"carName\": \"Car N°1\" }, 
                                    { \"carId\": \"2\", \"carName\": \"Car N°1\" }, 
                                    { \"businessId\": \"3\", \"carName\": \"Car N°1\" }
                                   ] }'''; // String encased in 3 single-quotations at start and end

Map<String, dynamic> map = jsonDecode(strVar);

print(map);