// 將shared_preferences包添加到您的pubspec.yaml文件中。
import 'package:shared_preferences/shared_preferences.dart';

// Storing a value
Future<void> saveData() async {
  final prefs = await SharedPreferences.getInstance();
  prefs.setString('username', 'John');
}

// Retrieving a value
Future<String> fetchData() async {
  final prefs = await SharedPreferences.getInstance();
  return prefs.getString('username');
}

// 將 sqflite 包添加到 pubspec.yaml 文件中。
import 'package:sqflite/sqflite.dart';
import 'package:path/path.dart';

// 初始化數(shù)據(jù)庫(kù)
Future<Database> initDatabase() async {
  final path = join(await getDatabasesPath(), 'my_database.db');
  return openDatabase(path, onCreate: (db, version) {
    return db.execute('CREATE TABLE my_table (id INTEGER PRIMARY KEY, name TEXT)');
  }, version: 1);
}

// 將數(shù)據(jù)插入數(shù)據(jù)庫(kù)
Future<void> insertData(String name) async {
  final db = await initDatabase();
  await db.insert('my_table', {'name': name});
}

// 從數(shù)據(jù)庫(kù)中查詢數(shù)據(jù)
Future<List<Map<String, dynamic>>?> fetchData() async {
  final db = await initDatabase();
  return db.query('my_table');
}

// 將 path_provider 包添加到 pubspec.yaml 文件中。
import 'dart:io';
import 'package:path_provider/path_provider.dart';

// 獲取應(yīng)用程序文檔目錄
Future<String> getFilePath() async {
  final directory = await getApplicationDocumentsDirectory();
  return File('${directory.path}/my_file.txt').path;
}

// 將數(shù)據(jù)寫入文件
Future<void> writeToFile(String data) async {
  final file = File(await getFilePath());
  await file.writeAsString(data);
}

// 從文件中讀取數(shù)據(jù)
Future<String> readFromFile() async {
  final file = File(await getFilePath());
  return file.readAsString();
}

// 將 Firebase 包添加到您的 pubspec.yaml 文件中。
import 'package:firebase_core/firebase_core.dart';
import 'package:cloud_firestore/cloud_firestore.dart';

// 初始化 Firebase
await Firebase.initializeApp();

// 將數(shù)據(jù)添加到 Firestore
Future<void> addData() async {
  final firestore = FirebaseFirestore.instance;
  await firestore.collection('users').doc('user1').set({'name': 'John'});
}

// 從 Firestore 檢索數(shù)據(jù)
Future<String> fetchData() async {
  final firestore = FirebaseFirestore.instance;
  final snapshot = await firestore.collection('users').doc('user1').get();
  return snapshot.data()['name'];
}