how to store api json data into sqflite in flutter

Question

I am trying to store the api data in sqflite but getting "Exception has occurred. _CastError (type 'String' is not a subtype of type 'List' in type cast)". Please help me to resolve this.

This is to fetch the api data.(employee_api_provider.dart)

//import 'package:flutter/cupertino.dart';
import 'package:flutter_app/src/models/employee_model.dart';
import 'package:flutter_app/src/providers/db_provider.dart';
import 'package:dio/dio.dart';

class EmployeeApiProvider {
  Future<List<Employee>> getAllEmployees() async {
    var url = "url";
    Response response = await Dio().get(url);
    //debugPrint(response);

    return (response.data as List).map((employee) {
      print('Inserting $employee');
      DBProvider.db.createEmployee(Employee.fromJson(employee));
    }).toList();
  }
}

I have created the model class(employee_model.dart)

 import 'dart:convert';

    List<Employee> employeeFromJson(String str) =>
        List<Employee>.from(json.decode(str).map((x) => Employee.fromJson(x)));

    String employeeToJson(List<Employee> data) =>
        json.encode(List<dynamic>.from(data.map((x) => x.toJson())));

    class Employee {
      int id;
      int eventId;
      String menuName;
      String menuIcon;
      String deepLinkName;
      int displayStatus;
      int orderId;
      String dateTime;

      Employee({
        this.id,
        this.eventId,
        this.menuName,
        this.menuIcon,
        this.deepLinkName,
        this.displayStatus,
        this.orderId,
        this.dateTime,
      });

      factory Employee.fromJson(Map<String, dynamic> json) => Employee(
            id: json["Id"],
            eventId: json["Event_Id"],
            menuName: json["Menu_Name"],
            menuIcon: json["Menu_Icon"],
            deepLinkName: json["Deep_Link_Name"],
            displayStatus: json["Display_Status"],
            orderId: json["Order_Id"],
            dateTime: json["Date_Time"],
          );

      Map<String, dynamic> toJson() => {
            "Id": id,
            "Event_Id": eventId,
            "Menu_Name": menuName,
            "Menu_Icon": menuIcon,
            "Deep_Link_Name": deepLinkName,
            "Display_Status": displayStatus,
            "Order_Id": orderId,
            "Date_Time": dateTime,
          };
    }

db_provider.dart

import 'dart:io';
import 'package:flutter_app/src/models/employee_model.dart';
import 'package:path/path.dart';

import 'package:path_provider/path_provider.dart';
import 'package:sqflite/sqflite.dart';

class DBProvider {
  static Database _database;
  static final DBProvider db = DBProvider._();

  DBProvider._();

  Future<Database> get database async {
    // If database exists, return database
    if (_database != null) return _database;

    // If database don't exists, create one
    _database = await initDB();

    return _database;
  }

  // Create the database and the Employee table
  initDB() async {
    Directory documentsDirectory = await getApplicationDocumentsDirectory();
    final path = join(documentsDirectory.path, 'menu.db');

    return await openDatabase(path, version: 1, onOpen: (db) {},
        onCreate: (Database db, int version) async {
      await db.execute('CREATE TABLE Employee('
          'id INTEGER,'
          'eventId INTEGER,'
          'menuName TEXT,'
          'menuIcon TEXT,'
          'deepLinkName TEXT,'
          'displayStatus INTEGER,'
          'orderId INTEGER,'
          'DateTime TEXT'
          ')');
    });
  }

  // Insert employee on database
  createEmployee(Employee newEmployee) async {
    await deleteAllEmployees();
    final db = await database;
    final res = await db.insert('Employee', newEmployee.toJson());

    return res;
  }

  // Delete all employees
  Future<int> deleteAllEmployees() async {
    final db = await database;
    final res = await db.rawDelete('DELETE FROM Employee');

    return res;
  }

  Future<List<Employee>> getAllEmployees() async {
    final db = await database;
    final res = await db.rawQuery("SELECT * FROM EMPLOYEE");

    List<Employee> list =
        res.isNotEmpty ? res.map((c) => Employee.fromJson(c)).toList() : [];

    return list;
  }
}

db_provider.dart

@VijayaRagavan i have added the full code. please check. i am getting error in employee_api_provider.dart('return (response.data as List).map((employee) {). please check — arul
– arul, Commented Dec 21, 2019 at 9:14

Crazy Lazy Cat · Accepted Answer · 2019-12-23 07:54:16Z

1

Use this in employee_api_provider.dart

return employeeFromJson(response.data).map((employee) {
  print('Inserting $employee');
  DBProvider.db.createEmployee(employee);
}).toList();

instead of

return (response.data as List).map((employee) {
  print('Inserting $employee');
  DBProvider.db.createEmployee(Employee.fromJson(employee));
}).toList();

edited Dec 23, 2019 at 7:54

answered Dec 21, 2019 at 9:47

Crazy Lazy Cat

15.3k5 gold badges36 silver badges55 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

arul Over a year ago

thanks for your help. I tried but getting error "The argument type 'Response' can't be assigned to the parameter type 'String'.dart(argument_type_not_assignable)"

Crazy Lazy Cat Over a year ago

@arul sorry. I used response instead of response.data. I updated the answer. pls check it again

user7418129 Over a year ago

Still I'm getting this error: <A value of type 'List<Null>' can't be returned from the method 'getAllEmployees' because it has a return type of 'Future<List<employee_model>>>

Major Akash · Accepted Answer · 2021-11-19 06:44:33Z

0

Please use this flutter plugin json_store

answered Nov 19, 2021 at 6:44

Major Akash

2091 silver badge5 bronze badges

Collectives™ on Stack Overflow

how to store api json data into sqflite in flutter

2 Answers 2

3 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related