【FLUTTER ANDROID STUDIO and IOS】Sqlite CRUD

 import 'package:flutter/material.dart';

import 'package:flutter/services.dart';
import 'model.dart';
import 'dataBase.dart';
import 'itemCardWidget.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
          brightness: Brightness.dark,
          floatingActionButtonTheme: FloatingActionButtonThemeData(
            backgroundColor: Colors.blue,
          )),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final DbManager dbManager = new DbManager();

  Model model;
  List<Model> modelList;
  TextEditingController input1 = TextEditingController();
  TextEditingController input2 = TextEditingController();
  FocusNode input1FocusNode;
  FocusNode input2FocusNode;

  @override
  void initState() {
    input1FocusNode = FocusNode();
    input2FocusNode = FocusNode();
    super.initState();
  }

  @override
  void dispose() {
    input1FocusNode.dispose();
    input2FocusNode.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Sqlite Demo'),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          showDialog(
              context: context,
              builder: (context) {
                return DialogBox().dialog(
                  context: context,
                  onPressed: () {
                    Model model = new Model(
                        fruitName: input1.text, quantity: input2.text);
                    dbManager.insertModel(model);
                    setState(() {
                      input1.text = "";
                      input2.text = "";
                    });
                    Navigator.of(context).pop();
                  },
                  textEditingController1: input1,
                  textEditingController2: input2,
                  input1FocusNode: input1FocusNode,
                  input2FocusNode: input2FocusNode,
                );
              });
        },
        child: Icon(
          Icons.add,
          color: Colors.white,
        ),
      ),
      body: FutureBuilder(
        future: dbManager.getModelList(),
        builder: (context, snapshot) {
          if (snapshot.hasData) {
            modelList = snapshot.data;
            return ListView.builder(
              itemCount: modelList.length,
              itemBuilder: (context, index) {
                Model _model = modelList[index];
                return ItemCard(
                  model: _model,
                  input1: input1,
                  input2: input2,
                  onDeletePress: () {
                    dbManager.deleteModel(_model);
                    setState(() {});
                  },
                  onEditPress: () {
                    input1.text = _model.fruitName;
                    input2.text = _model.quantity;
                    showDialog(
                        context: context,
                        builder: (context) {
                          return DialogBox().dialog(
                              context: context,
                              onPressed: () {
                                Model __model = Model(
                                    id: _model.id,
                                    fruitName: input1.text,
                                    quantity: input2.text);
                                dbManager.updateModel(__model);

                                setState(() {
                                  input1.text = "";
                                  input2.text = "";
                                });
                                Navigator.of(context).pop();
                              },
                              textEditingController2: input2,
                              textEditingController1: input1);
                        });
                  },
                );
              },
            );
          }
          return Center(
            child: CircularProgressIndicator(),
          );
        },
      ),
    );
  }
}

class Model {
  int id;
  String fruitName;
  String quantity;

  Model({this.id, this.fruitName, this.quantity});

  Model fromJson(json) {
    return Model(
        id: json['id'],
        fruitName: json['fruitName'],
        quantity: json['quantity']);
  }

  Map<String, dynamic> toJson() {
    return {'fruitName': fruitName, 'quantity': quantity};
  }

}

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

import 'model.dart';

class DbManager {
  Database _database;

  Future openDb() async {
    _database = await openDatabase(join(await getDatabasesPath(), "ss.db"),
        version: 1, onCreate: (Database db, int version) async {
          await db.execute(
            "CREATE TABLE model(id INTEGER PRIMARY KEY autoincrement, fruitName TEXT, quantity TEXT)",
          );
        });
    return _database;
  }

  Future insertModel(Model model) async {
    await openDb();
    return await _database.insert('model', model.toJson());
  }

  Future<List<Model>> getModelList() async {
    await openDb();
    final List<Map<String, dynamic>> maps = await _database.query('model');

    return List.generate(maps.length, (i) {
      return Model(
          id: maps[i]['id'],
          fruitName: maps[i]['fruitName'],
          quantity: maps[i]['quantity']);
    });
  }

  Future<int> updateModel(Model model) async {
    await openDb();
    return await _database.update('model', model.toJson(),
        where: "id = ?", whereArgs: [model.id]);
  }

  Future<void> deleteModel(Model model) async {
    await openDb();
    await _database.delete('model', where: "id = ?", whereArgs: [model.id]);
  }
}

import 'package:flutter/material.dart';
import 'dataBase.dart';
import 'model.dart';

class ItemCard extends StatefulWidget {
  Model model;
  TextEditingController input1;
  TextEditingController input2;
  Function onDeletePress;
  Function onEditPress;

  ItemCard({this.model,
    this.input1,
    this.input2,
    this.onDeletePress,
    this.onEditPress});

  @override
  _ItemCardState createState() => _ItemCardState();
}

class _ItemCardState extends State<ItemCard> {
  final DbManager dbManager = new DbManager();

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.all(8.0),
      child: Card(
        child: Padding(
          padding: const EdgeInsets.all(8.0),
          child: Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: <Widget>[
              Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: <Widget>[
                  Text(
                    'Name: ${widget.model.fruitName}',
                    style: TextStyle(fontSize: 15),
                  ),
                  Text(
                    'Quantity: ${widget.model.quantity}',
                    style: TextStyle(
                      fontSize: 15,
                    ),
                  ),
                ],
              ),
              Row(
                children: [
                  CircleAvatar(
                    backgroundColor: Colors.white,
                    child: IconButton(
                      onPressed: widget.onEditPress,
                      icon: Icon(
                        Icons.edit,
                        color: Colors.blueAccent,
                      ),
                    ),
                  ),
                  SizedBox(
                    width: 15,
                  ),
                  CircleAvatar(
                    backgroundColor: Colors.white,
                    child: IconButton(
                      onPressed: widget.onDeletePress,
                      icon: Icon(
                        Icons.delete,
                        color: Colors.red,
                      ),
                    ),
                  )
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class DialogBox {
  Widget dialog({BuildContext context,
    Function onPressed,
    TextEditingController textEditingController1,
    TextEditingController textEditingController2,
    FocusNode input1FocusNode,
    FocusNode input2FocusNode}) {
    return AlertDialog(
      title: Text("Enter Data"),
      content: Container(
        height: 100,
        child: Column(
          children: [
            TextFormField(
              controller: textEditingController1,
              keyboardType: TextInputType.text,
              focusNode: input1FocusNode,
              decoration: InputDecoration(hintText: "Fruit Name"),
              autofocus: true,
              onFieldSubmitted: (value) {
                input1FocusNode.unfocus();
                FocusScope.of(context).requestFocus(input2FocusNode);
              },
            ),
            TextFormField(
              controller: textEditingController2,
              keyboardType: TextInputType.number,
              focusNode: input2FocusNode,
              decoration: InputDecoration(hintText: "Quantity"),
              onFieldSubmitted: (value) {
                input2FocusNode.unfocus();
              },
            ),
          ],
        ),
      ),
      actions: [
        MaterialButton(
          onPressed: () {
            Navigator.of(context).pop();
          },
          color: Colors.blueGrey,
          child: Text(
            "Cancel",
          ),
        ),
        MaterialButton(
          onPressed: onPressed,
          child: Text("Submit"),
          color: Colors.blue,
        )
      ],
    );
  }
}