ऑफ़लाइन अंतर्राष्ट्रीयकरण ऐप कैसे बनाएं:स्क्लाइट डेटाबेस का उपयोग करें

https://pub.dev/packages/floor

संदर्भ कॉन्फ़िगर करें pubspec.yaml स्पंदन परियोजना में आश्रित पुस्तकालय का

dependencies:
  flutter:
    sdk: flutter
  floor: ^1.2.0

dev_dependencies:
  floor_generator: ^1.2.0
  build_runner: ^2.1.2

इकाई बनाएं और देखें [project_root]/lib/app/data/entity/vegetalbe.dart

import 'package:floor/floor.dart';

@Entity(tableName: "vegetables")
class Vegetable {
  @PrimaryKey(autoGenerate: true)
  final int? id;

  final String name;

  final String locale;

  final String desc;

  @ColumnInfo(name: 'created_at')
  final int createTime;

  @ColumnInfo(name: 'updated_at')
  final int updateTime;

  Vegetable(
    this.id,
    this.name,
    this.locale,
    this.desc, {
    int? createTime,
    int? updateTime,
  })  : this.createTime = createTime ?? DateTime.now().millisecondsSinceEpoch,
        this.updateTime = updateTime ?? DateTime.now().millisecondsSinceEpoch;
}

@DatabaseView(
    'SELECT v.id,   v.name, v.desc, v.locale,   uf.hash,    uf.ext,     v.created_at,   v.updated_at from   vegetables v LEFT OUTER JOIN upload_file_morph ufm on   v.id = ufm.related_id LEFT OUTER JOIN upload_file uf on ufm.upload_file_id = uf.id;',
    viewName: "vegetables_v")
class VegetableV {
  final int id;
  final String name;
  final String locale;
  final String? desc;
  final String? hash;
  final String? ext;

  @ColumnInfo(name: 'created_at')
  final int createTime;

  @ColumnInfo(name: 'updated_at')
  final int updateTime;

  VegetableV(
    this.id,
    this.name,
    this.locale,
    this.desc,
    this.hash,
    this.ext, {
    int? createTime,
    int? updateTime,
  })  : this.createTime = createTime ?? DateTime.now().millisecondsSinceEpoch,
        this.updateTime = updateTime ?? DateTime.now().millisecondsSinceEpoch;
}

विशिष्ट विवरण के लिए, कृपया देखें https://floor.codes/database-views/

दृश्य के अनुसार "डेटा एक्सेस ऑब्जेक्ट" बनाएं[project_root]/lib/app/data/dao/vegetalbe_dao.dart

import 'package:floor/floor.dart';
import 'package:strapi_flutter_internation_poc/app/data/entity/vegetable.dart';

@dao
abstract class VegetableDao {
  @Query('SELECT * FROM vegetables_v')
  Future<List<VegetableV>> findAll();
}

डेटाबेस प्रबंधन वर्ग बनाएँ [project_root]/lib/app/data/database.dart

import 'dart:async';
import 'package:floor/floor.dart';
import 'package:sqflite/sqflite.dart' as sqflite;
// daos
import 'dao/vegetable_dao.dart';
// entitys
import 'entity/vegetable.dart';

part 'database.g.dart'; // the generated code will be there

@Database(version: 1, entities: [Vegetable], views: [VegetableV])
abstract class AppDatabase extends FloorDatabase {
  VegetableDao get vegetableDao;
}

फ़्लोर का कोड जनरेटर चलाएँ

flutter packages pub run build_runner build
[INFO] Generating build script...
[INFO] Generating build script completed, took 480ms

[INFO] Initializing inputs
[INFO] Reading cached asset graph...
[INFO] Reading cached asset graph completed, took 67ms

[INFO] Checking for updates since last build...
[INFO] Checking for updates since last build completed, took 651ms

[INFO] Running build...
[INFO] 1.1s elapsed, 0/1 actions completed.
[INFO] 2.2s elapsed, 0/1 actions completed.
[INFO] 4.0s elapsed, 0/1 actions completed.
[INFO] 8.4s elapsed, 0/1 actions completed.
[INFO] Running build completed, took 8.8s

[INFO] Caching finalized dependency graph...
[INFO] Caching finalized dependency graph completed, took 34ms

[INFO] Succeeded after 8.8s with 2 outputs (2 actions)

यह एक database.g.dart उत्पन्न करेगा उसी निर्देशिका में database.dart

डीबी सेवा बनाने के लिए GetX की सेवा योजना का उपयोग करें [project_root]/lib/app/common/services/db_service.dart.dart

कृपया यहां विशेष ध्यान दें

फ़्लोर के आधिकारिक दस्तावेज़ीकरण के विपरीत, फ़्लोर इकाई के आधार पर एक sqlite डेटाबेस उत्पन्न करेगा। मैं नई डेटाबेस फ़ाइलों को उत्पन्न किए बिना मौजूदा डेटाबेस फ़ाइलों को उपयोग के लिए फ़्लोर को प्रदान करूंगा।

import 'dart:io';
import 'package:get/get.dart';
import 'package:path/path.dart';
import 'package:floor/floor.dart';
import 'package:flutter/services.dart';
import 'package:sqflite/sqflite.dart';
import 'package:strapi_flutter_internation_poc/app/data/database.dart';

class DbService extends GetxService {
  static DbService get to => Get.find();

  late AppDatabase db;

  Future<DbService> init() async {
    final callback = Callback(
      onCreate: (database, version) {},
      onOpen: (database) {
        print('onOpen database');
        getDatabasesPath().then((value) => print(value));
      },
      onUpgrade: (database, startVersion, endVersion) {},
    );

    var dbDir = await getDatabasesPath();
    var dbPath = join(dbDir, "app_database.db");

    await deleteDatabase(dbPath);

    ByteData data = await rootBundle.load("assets/db/data.db");
    List<int> bytes =
        data.buffer.asUint8List(data.offsetInBytes, data.lengthInBytes);
    await File(dbPath).writeAsBytes(bytes);

    db = await $FloorAppDatabase
        .databaseBuilder(dbPath)
        .addCallback(callback)
        .build();
    return this;
  }
}

तत्काल DbService [project_root]/lib/main.dart

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await initServices();

  runApp(
    GetMaterialApp(
      title: "Application",
      initialRoute: AppPages.INITIAL,
      getPages: AppPages.routes,
    ),
  );
}

Future<void> initServices() async {
  print('starting services ...');
  await Get.putAsync(() => DbService().init());
  print('All services started...');
}

स्क्लाइट डेटाबेस [project_root]/lib/app/modules/home/controllers/home_controller.dart को पढ़ने के लिए home_controller कोड को संशोधित करें।

import 'package:get/get.dart';
import 'package:strapi_flutter_internation_poc/app/common/services/db_service.dart';
import 'package:strapi_flutter_internation_poc/app/data/entity/vegetable.dart';

class HomeController extends GetxController {
  final vegetables = Rx<List<VegetableV>>([]);

  @override
  void onInit() {
    super.onInit();
  }

  @override
  void onReady() {
    super.onReady();
  }

  Future<void> getAllVegetables() async {
    final result = await DbService.to.db.vegetableDao.findAll();
    vegetables.value = result;
  }

  @override
  void onClose() {}
}

संक्षेप में इसका परीक्षण करें

controller.getAllVegetables();

  Future<void> getAllVegetables() async {
    final result = await DbService.to.db.vegetableDao.findAll();
    vegetables.value = result;
    print(result);
  }

बाहर

I/flutter ( 7396): starting services ...
I/flutter ( 7396): onOpen database
I/flutter ( 7396): /data/user/0/com.nasawz.strapi_flutter_internation_poc.strapi_flutter_internation_poc/databases
I/flutter ( 7396): All services started...
[GETX] Instance "DbService" has been created
[GETX] Instance "DbService" has been initialized
[GETX] Instance "GetMaterialController" has been created
[GETX] Instance "GetMaterialController" has been initialized
[GETX] GOING TO ROUTE /home
[GETX] Instance "HomeController" has been created
[GETX] Instance "HomeController" has been initialized
I/flutter ( 7396): [Instance of 'VegetableV', Instance of 'VegetableV', Instance of 'VegetableV', Instance of 'VegetableV', Instance of 'VegetableV', Instance of 'VegetableV', Instance of 'VegetableV', Instance of 'VegetableV']

सफलता! डेटा पढ़ा जाता है।

इंटरफ़ेस पर डेटा प्रदर्शित करने के लिए GetX की Obx सुविधा का उपयोग करें

import 'package:flutter/material.dart';

import 'package:get/get.dart';
import '../controllers/home_controller.dart';

class HomeView extends GetView<HomeController> {
  @override
  Widget build(BuildContext context) {
    controller.getAllVegetables();
    return Scaffold(
      appBar: AppBar(
        title: Text('Vegetables'),
        centerTitle: true,
      ),
      body: Obx(() => ListView.builder(
          itemCount: controller.vegetables.value.length,
          itemBuilder: (context, index) {
            var vegetable = controller.vegetables.value[index];
            return Padding(
              padding: const EdgeInsets.all(18.0),
              child: Container(
                child: Row(
                  children: [
                    Container(
                      // color: Colors.red,
                      child: Image.asset(
                        'strapi/public/uploads/thumbnail_${vegetable.hash}${vegetable.ext}',
                        fit: BoxFit.contain,
                        width: 140,
                        height: 140,
                      ),
                    ),
                    Container(
                      width: Get.width - 18 * 2 - 140 - 18,
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          Text(
                            vegetable.name,
                            style: Get.textTheme.headline6,
                          ),
                          Text(
                            vegetable.desc!,
                            style: Get.textTheme.subtitle1,
                            maxLines: 1,
                            overflow: TextOverflow.ellipsis,
                          ),
                        ],
                      ),
                    ),
                  ],
                ),
              ),
            );
          })),
    );
  }
}