how to call dbhelper insert or update or delete

Question

import 'dart:async';

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

import '../models/product.dart';


class DbHelper {

late Database ?_db;
 static final DbHelper instance=DbHelper();
 Future<Database> get db async{
 if(_db==null){
   _db=await initializedb();
 }
  return _db!;
}

static Future<Database> initializedb()async {
  String dbPath = join(await getDatabasesPath(),"etrade.db");
  var etradeDB = await openDatabase(dbPath,version: 1,onCreate: createDb);
  return etradeDB;
}

void createDb(Database db, int version)async {
await db.execute("Create table products(id integer primary key, name text, description 
text, unitPrice integer)");
}

Future<List<Product>> getProducts() async{
Database db = await this.db;
var result = await db.query("products");
return List.generate(result.length, (i){
  return Product.fromObject(result[i]);
});


}
Future<int> insert(Product product) async {
Database db = await this.db;
var result = await db.insert("products",product.toMap());
return result;
}

Future<int> delete(int id) async {
var db = await this.db;
var result = await db.rawDelete("delete from products where id=$id");
return result;
}

Future<int> update(Product product) async {
var db = await this.db;
var result = await db.update("product", product.toMap(), where: "id=?",whereArgs: 
[product.id]);
return result;
}

}

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
 import 'package:sqflite_demo/data/dbHelper.dart';


class ProductAdd extends StatefulWidget {
@override 
State<StatefulWidget> createState() {
return ProductAddState();
}
}

class ProductAddState extends State with DbHelper{
initState() {
myAsyncInit();
}

myAsyncInit() async {
//do async stuff
}
var  Dbhelper = DbHelper;
final txtName = TextEditingController();
final txtDescription = TextEditingController();
var txtUnitPrice = TextEditingController();

@override
Widget build(BuildContext context) {
return Scaffold(
  resizeToAvoidBottomInset: false,
  appBar: AppBar(
    title: Text("Yeni Ürün ekle"),
  ),
  body: Padding(
    padding: EdgeInsets.all(30.0),
    child: Column(
      children: <Widget>[
        buildNameField(),
        buildDescriptionField(),
        buildUnitPriceField(),
        buildSaveButton()
      ],
    ),
  ),
);
}

 buildUnitPriceField() {
 return TextField(
  keyboardType: TextInputType.number,
  inputFormatters: <TextInputFormatter>[
    FilteringTextInputFormatter.digitsOnly
  ],
  decoration: InputDecoration(labelText: "Birim fiyatı", hintText: "20"),
  controller: txtName,
 );
}

buildNameField() {
return TextField(
  decoration: InputDecoration(labelText: "Ürün adı", hintText: "Tohum"),
  controller: txtDescription,
);
}

buildDescriptionField() {
return TextField(
  decoration: const InputDecoration(
      labelText: "Ürün açıklaması", hintText: "Domates"),
  controller: txtUnitPrice,
);
}

buildSaveButton() {
return FlatButton(
  onPressed: () {
    addProduct();
  },
  child: const Text("Ekle"),
);
}

void addProduct() async {

await Dbhelper.insert;
}
}

I want to call insert from the db helper below, the error it gives is as follows The getter 'insert' isn't defined for the type 'Type'. (Documentation) Try importing the library that defines 'insert', correcting the name to the name of an existing getter, or defining a getter or field named 'insert'.

score 0 · Answer 1 · answered Mar 17 '22 at 13:15

First if you want to create a singleton class do it like this,

class DbHelper {

static final DbHelper instance= DbHelper._();//change to this
...
}

second, When using singleton no need to create it's instance, initialise that class in main or some root widget. like this,

void main()async{
await DbHelper.init();
...
}

third, now where you want to use this functions,

class ProductAdd extends StatefulWidget {
  const ProductAdd({Key? key}) : super(key: key);

  @override
  State<MyApp> createState() => _ ProductAddState();
}

class _ ProductAddState extends State< ProductAdd> {
// you actually don't need "mixin" just directly use it.


...
void addProduct() async {
await Dbhelper.insert();
    }
  }
}

more about singleton, How do you build a Singleton in Dart?

how to call dbhelper insert or update or delete

1 Answers1