Flutter键值文件存储插件flutter_key_value_file_storage的使用

Flutter键值文件存储插件flutter_key_value_file_storage的使用

这是一个用于Flutter文件存储的实现。例如，keychain有一个软限制为4KB。使用文件系统，我们可以存储更大的内容。

使用

import 'package:flutter_key_value_file_storage/flutter_key_value_file_storage.dart';
import 'package:flutter_secure_storage/flutter_secure_storage.dart';

// 创建存储对象
final storage = FlutterKeyValueFileStorage(FlutterSecureStorage());

// 读取值
final value = await storage.read<String>(key: key);

// 读取所有值
Map<String, String> allValues = await storage.readAll();

// 删除特定值
await storage.delete(key: key);

// 删除所有值
await storage.deleteAll();

// 写入值
await storage.write(key: key, value: value);

示例代码

import 'package:flutter/material.dart';
import 'package:flutter_key_value_file_storage/flutter_key_value_file_storage.dart';
import 'package:flutter_secure_storage/flutter_secure_storage.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatefulWidget {
  const MyApp({super.key});

  [@override](/user/override)
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  String _content = ''; // 输入框中的内容
  String _loadedContent = ''; // 加载后的内容
  String _key = ''; // 存储的键
  bool _loading = false; // 加载状态
  late final FlutterKeyValueFileStorage _fileStorage; // 文件存储对象

  [@override](/user/override)
  void initState() {
    super.initState();
    _fileStorage = FlutterKeyValueFileStorage(const FlutterSecureStorage()); // 初始化文件存储对象
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Flutter文件存储应用'),
        ),
        body: SafeArea(
          child: Padding(
            padding: const EdgeInsets.all(8),
            child: Column(
              children: [
                TextField(
                  decoration: const InputDecoration(
                    labelText: '键',
                  ),
                  onChanged: (value) {
                    setState(() {
                      _key = value;
                    });
                  },
                ),
                TextField(
                  decoration: const InputDecoration(
                    labelText: '内容',
                  ),
                  onChanged: (value) {
                    setState(() {
                      _content = value;
                    });
                  },
                ),
                MaterialButton(
                  child: const Text('保存'),
                  onPressed: () async {
                    setState(() {
                      _loading = true;
                    });
                    await _fileStorage.write(key: _key, value: _content); // 将内容写入文件存储
                    setState(() {
                      _loading = false;
                    });
                  },
                ),
                MaterialButton(
                  child: const Text('根据键加载'),
                  onPressed: () async {
                    setState(() {
                      _loading = true;
                    });
                    final content = await _fileStorage.read<String>(key: _key); // 从文件存储中读取内容
                    setState(() {
                      _loadedContent = content ?? '';
                      _loading = false;
                    });
                  },
                ),
                if (_loading) ...[
                  const CircularProgressIndicator(), // 显示加载指示器
                ] else ...[
                  Text('从文件加载的内容: $_loadedContent'), // 显示加载的内容
                ],
              ],
            ),
          ),
        ),
      ),
    );
  }
}