flutter - 如何在 Flutter 中设置本地身份验证？

Question

我已将 firebase 登录连接到我的测试应用程序，并想在那里使用本地身份验证。我看过很多基于 local_auth 包的示例，但它们只显示了如何在本地进行身份验证，但我想在身份验证后使用电子邮件和密码。

为了更清晰，我从媒体上读了一篇帖子，上面写着:

** 当用户在首次登录/注册后决定使用上述方法激活身份验证时，他/她实际上说将我的登录凭据保存在本地主机中，没有注册指纹和面部 ID 的人无法访问。因此，当用户登录并决定使用此方法时，它基本上会从本地存储的位置获取登录凭据。 **

但是我该如何在 flutter 中实现它呢？

Answer 1

您需要像这个示例一样存储您的凭据。请看看

---

  dependencies:
          flutter_secure_storage: ^5.0.2

---

import 'dart:async';
import 'dart:io';
import 'dart:math';

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

void main() {
  runApp(const MaterialApp(home: ItemsWidget()));
}

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

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

enum _Actions { deleteAll }
enum _ItemActions { delete, edit, containsKey }

class _ItemsWidgetState extends State<ItemsWidget> {
  final _storage = const FlutterSecureStorage();
  final _accountNameController =
      TextEditingController(text: 'flutter_secure_storage_service');

  List<_SecItem> _items = [];

  @override
  void initState() {
    super.initState();

    _accountNameController.addListener(() => _readAll());
    _readAll();
  }

  Future<void> _readAll() async {
    final all = await _storage.readAll(
        iOptions: _getIOSOptions(), aOptions: _getAndroidOptions());
    setState(() {
      _items = all.entries
          .map((entry) => _SecItem(entry.key, entry.value))
          .toList(growable: false);
    });
  }

  void _deleteAll() async {
    await _storage.deleteAll(
        iOptions: _getIOSOptions(), aOptions: _getAndroidOptions());
    _readAll();
  }

  void _addNewItem() async {
    final String key = _randomValue();
    final String value = _randomValue();

    await _storage.write(
        key: key,
        value: value,
        iOptions: _getIOSOptions(),
        aOptions: _getAndroidOptions());
    _readAll();
  }

  IOSOptions _getIOSOptions() => IOSOptions(
        accountName: _getAccountName(),
      );

  AndroidOptions _getAndroidOptions() => const AndroidOptions(
        encryptedSharedPreferences: true,
      );

  String? _getAccountName() =>
      _accountNameController.text.isEmpty ? null : _accountNameController.text;

  @override
  Widget build(BuildContext context) => Scaffold(
        appBar: AppBar(
          title: const Text('Plugin example app'),
          actions: <Widget>[
            IconButton(
                key: const Key('add_random'),
                onPressed: _addNewItem,
                icon: const Icon(Icons.add)),
            PopupMenuButton<_Actions>(
                key: const Key('popup_menu'),
                onSelected: (action) {
                  switch (action) {
                    case _Actions.deleteAll:
                      _deleteAll();
                      break;
                  }
                },
                itemBuilder: (BuildContext context) =>
                    <PopupMenuEntry<_Actions>>[
                      const PopupMenuItem(
                        key: Key('delete_all'),
                        value: _Actions.deleteAll,
                        child: Text('Delete all'),
                      ),
                    ])
          ],
        ),
        body: Column(
          children: [
            if (!kIsWeb && Platform.isIOS)
              Padding(
                padding: const EdgeInsets.symmetric(horizontal: 16),
                child: TextFormField(
                  controller: _accountNameController,
                  decoration:
                      const InputDecoration(labelText: 'kSecAttrService'),
                ),
              ),
            Expanded(
              child: ListView.builder(
                itemCount: _items.length,
                itemBuilder: (BuildContext context, int index) => ListTile(
                  trailing: PopupMenuButton(
                      key: Key('popup_row_$index'),
                      onSelected: (_ItemActions action) =>
                          _performAction(action, _items[index], context),
                      itemBuilder: (BuildContext context) =>
                          <PopupMenuEntry<_ItemActions>>[
                            PopupMenuItem(
                              value: _ItemActions.delete,
                              child: Text(
                                'Delete',
                                key: Key('delete_row_$index'),
                              ),
                            ),
                            PopupMenuItem(
                              value: _ItemActions.edit,
                              child: Text(
                                'Edit',
                                key: Key('edit_row_$index'),
                              ),
                            ),
                            PopupMenuItem(
                              value: _ItemActions.containsKey,
                              child: Text(
                                'Contains Key',
                                key: Key('contains_row_$index'),
                              ),
                            ),
                          ]),
                  title: Text(
                    _items[index].value,
                    key: Key('title_row_$index'),
                  ),
                  subtitle: Text(
                    _items[index].key,
                    key: Key('subtitle_row_$index'),
                  ),
                ),
              ),
            ),
          ],
        ),
      );

  Future<void> _performAction(
      _ItemActions action, _SecItem item, BuildContext context) async {
    switch (action) {
      case _ItemActions.delete:
        await _storage.delete(
            key: item.key,
            iOptions: _getIOSOptions(),
            aOptions: _getAndroidOptions());
        _readAll();

        break;
      case _ItemActions.edit:
        final result = await showDialog<String>(
            context: context,
            builder: (context) => _EditItemWidget(item.value));
        if (result != null) {
          await _storage.write(
              key: item.key,
              value: result,
              iOptions: _getIOSOptions(),
              aOptions: _getAndroidOptions());
          _readAll();
        }
        break;
      case _ItemActions.containsKey:
        final result = await _storage.containsKey(key: item.key);
        ScaffoldMessenger.of(context).showSnackBar(SnackBar(
          content: Text('Contains Key: $result'),
          // backgroundColor: Colors.green,
          duration: const Duration(seconds: 4),
        ));
        break;
    }
  }

  String _randomValue() {
    final rand = Random();
    final codeUnits = List.generate(20, (index) {
      return rand.nextInt(26) + 65;
    });

    return String.fromCharCodes(codeUnits);
  }
}

class _EditItemWidget extends StatelessWidget {
  _EditItemWidget(String text)
      : _controller = TextEditingController(text: text);

  final TextEditingController _controller;

  @override
  Widget build(BuildContext context) {
    return AlertDialog(
      title: const Text('Edit item'),
      content: TextField(
        key: const Key('title_field'),
        controller: _controller,
        autofocus: true,
      ),
      actions: <Widget>[
        TextButton(
            key: const Key('cancel'),
            onPressed: () => Navigator.of(context).pop(),
            child: const Text('Cancel')),
        TextButton(
            key: const Key('save'),
            onPressed: () => Navigator.of(context).pop(_controller.text),
            child: const Text('Save')),
      ],
    );
  }
}

class _SecItem {
  _SecItem(this.key, this.value);

  final String key;
  final String value;
}