Copy flutter assets database inside application

dependencies:
  flutter:
  sqflite:
  path:

Future<String> initDatabase() async {


  var databasesPath = await getDatabasesPath();
  var path = join(databasesPath, "demo_asset_example.db");

// Check if the database exists
  var exists = await databaseExists(path);

  if (!exists) {
    // Should happen only the first time you launch your application
    print("Creating new copy from asset");

    // Make sure the parent directory exists
    try {
      await Directory(dirname(path)).create(recursive: true);
    } catch (_) {}

    // Copy from asset
    ByteData data = await rootBundle.load(join("assets", "example.db"));
    List<int> bytes =
    data.buffer.asUint8List(data.offsetInBytes, data.lengthInBytes);

    // Write and flush the bytes written
    await File(path).writeAsBytes(bytes, flush: true);

  } else {
    print("Reading Existing Database");
  }
// open the database
 // database = await openDatabase(path, readOnly: true);


  return path;
}

Future<String> readTables() async
{
  Database db = await database;
  var res=await  db.rawQuery("select * FROM  sqlite_master WHERE type ='table'");
  if(res.length>0)
  {
    return res.first.entries.toString();

  }
  return "No Tables found";
}

import 'dart:async';

import 'package:flutter/material.dart';

import 'databse.dart';

class AssetsDatabase extends StatefulWidget{
  @override
  _AssetsDatabaseState createState() => _AssetsDatabaseState();
}

class _AssetsDatabaseState extends State<AssetsDatabase> {

  bool readTable=false;
  String table_info="";
  final _tables = StreamController<String>();
  Sink get updateUser => _tables.sink;
  Stream<String> get user => _tables.stream;
  @override
  Widget build(BuildContext context) {
    // TODO: implement build


    return MaterialApp(home: Scaffold(
      appBar: AppBar(title: Text("Read Assets Database"),),
      body:
      Column(
        children: [
          FutureBuilder(
            builder:(context, snapshot)  {
              if (snapshot.hasData) {
              return  SingleChildScrollView(
                child: Card(
                  margin: EdgeInsets.all(8),
                  child: Column(
                    mainAxisSize: MainAxisSize.max,
                    children: [
                          Text("Database Created, Now you can load tables"),
                          RaisedButton(onPressed: (){
                          readTable=true;
                            readTablesFromDb();
                              },child: Text("Load Tables"),
                          ),

                          stream(),
                    ],

                  ),
                ),
              );
              }
              else{
                   return  Text("Database Not created");
              }


            } ,
            future: initDatabase(),
          ),

        ],
      ),

    ),);
  }
  stream()
  {
   return StreamBuilder<String>(
      initialData: "",
      stream: _tables.stream,
      builder: (context, snapshot) {
        if (snapshot.connectionState == ConnectionState.active)
          return Text(" ${snapshot.data}");
        if (snapshot.connectionState == ConnectionState.active)
          return   Text(" ${snapshot.data}");
        return CircularProgressIndicator();
      },
    );
  }

  readTablesFromDb()
  {
    if(readTable)
      (readTables().then((value) => {
        _tables.add(value)
      }));
    else   _tables.add("No Tables");
  }

}

import 'dart:io';

import 'package:flutter/services.dart';
import 'package:path/path.dart';
import 'package:sqflite/sqflite.dart';

 Database _database;
int _databaseVersion=1;
/// delete the db, create the folder and returnes its path

Future<String> readTables() async
{
  Database db = await database;
  var res=await  db.rawQuery("select * FROM  sqlite_master WHERE type ='table'");
  if(res.length>0)
  {
    //mapData.entries.map( (entry) => Weight(entry.key, entry.value)).toList();
    String s="";
    for(int k=0;k<res.length;k++)
      {
        print("reading ");

        for (var entry in res[k].entries) {
          print(entry.key);
          print(entry.value);
          if(entry.key=="tbl_name")
          s=s+ "Table Name: ${entry.value}\n";
          else if(entry.key=="sql")
            s=s+ "Table Query: ${entry.value}\n";
        }

        s=s+"  \n\n  -----------  \n\n";

      }
    return s;

  }
  return "No Tables found";
}

Future<String> readTables() async
{
  Database db = await database;
  var res=await  db.rawQuery("select * FROM  sqlite_master WHERE type ='table'");
  if(res.length>0)
  {
    return res.first.entries.toString();

  }
  return "No Tables found";
}

Future get database async {
  if (_database != null) return _database;
  // lazily instantiate the db the first time it is accessed
  _database = await _initDatabase();
  return _database;
}
_initDatabase() async {
  var databasesPath = await getDatabasesPath();
  var path = join(databasesPath, "demo_asset_example.db");

  return await openDatabase(path,
      version: _databaseVersion,
      onCreate: _onCreate);
}

// SQL code to create the database table
Future _onCreate(Database db, int version) async {

}