decode stored json result string in shared preferences - json

Question

When the app launch it triggers an API call and in my case, I want to store the response data for later use, so I used shared preferences for that and stored response data as a string. now I want to properly decode the data to use, from the stored string from shared preferences.
here is how I covert the data to string,
SharedPreferences prefs = await SharedPreferences.getInstance();
Response response = await _dio.post(
_baseUrl,
data: {"index": indexNum, "password": password},
options: Options(contentType: Headers.formUrlEncodedContentType),
);
if (response.statusCode == 200) {
var result = response.data;
//convert result data to string
var resultData = Result.encode(result);
// store the resultData in shared_preferences
prefs.setString('results', resultData);
}
encode method,
class Result {
Result({
required this.table,
required this.data,
});
String table;
List<Data> data;
factory Result.fromJson(Map<String, dynamic> json) => Result(
table: json["table"],
data: List<Data>.from(json["data"].map((x) => Data.fromJson(x))),
);
//encode method
static String encode(List<dynamic> results) => json.encode(
results.map((result) => result.toString()).toList(),
);
}
here is my approach to decode data from string,
getData() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
String? resultData = prefs.getString('results');
List<dynamic> decodedJson = jsonDecode(resultData!);
print(decodedJson);
}
resultData string,
resultData string after decode,
I am new to flutter and what I want is the proper way to decode this data from models. Below are my model classes.
import 'dart:convert';
class Result {
Result({
required this.table,
required this.data,
});
String table;
List<Data> data;
factory Result.fromJson(Map<String, dynamic> json) => Result(
table: json["table"],
data: List<Data>.from(json["data"].map((x) => Data.fromJson(x))),
);
static String encode(List<dynamic> results) => json.encode(
results.map((result) => result.toString()).toList(),
);
}
class Data {
Data({
required this.subjectName,
required this.year,
required this.credits,
required this.sOrder,
required this.result,
required this.onlineAssignmentResult,
});
String subjectName;
String year;
String credits;
String sOrder;
String result;
String onlineAssignmentResult;
factory Data.fromJson(json) => Data(
subjectName: json["subject_name"],
year: json["year"],
credits: json["credits"],
sOrder: json["s_order"],
result: json["result"],
onlineAssignmentResult: json["online_assignment_result"],
);
}
Appreciate your time and help.

Answer 1

Your JSON is in the wrong syntax for Flutter to decode with jsonDecode()
All strings and variable names need to be enclosed in " or '
I.e. {subject_name: should be {"subject_name":