flutter_async_cache 0.0.3

flutter_async_cache: ^0.0.3 copied to clipboard

example/lib/main.dart

import 'package:flutter/material.dart';
import 'package:flutter_async_cache/flutter_async_cache.dart';
import 'dart:convert';
import 'package:http/http.dart' as http;

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

class CacheExampleApp extends StatelessWidget {
  const CacheExampleApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Async Cache Example',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        useMaterial3: true,
      ),
      home: const CacheExamplePage(),
    );
  }
}

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

  @override
  State<CacheExamplePage> createState() => _CacheExamplePageState();
}

class _CacheExamplePageState extends State<CacheExamplePage> {
  late CacheManager cache;
  String currentData = 'No data loaded';
  String cacheStats = '';
  List<String> events = [];

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

  Future<void> _initializeCache() async {
    cache = CacheManager(
      config: CacheConfig(
        maxEntries: 50,
        maxSize: 10 * 1024 * 1024, // 10MB
        defaultTtl: Duration(minutes: 5),
        enableOfflineMode: true,
        enableBackgroundRefresh: true,
        backgroundRefreshInterval: Duration(minutes: 2),
        enableAutoCleanup: true,
        autoCleanupInterval: Duration(minutes: 10),
        evictionStrategy: EvictionStrategy.lru,
        enableStatistics: true,
        enablePersistence: true,
      ),
    );

    await cache.initialize();

    // Listen to cache events
    cache.onCacheEvent.listen((event) {
      setState(() {
        events.add(
            '${DateTime.now().toString().substring(11, 19)}: ${event.runtimeType}');
        if (events.length > 10) {
          events.removeAt(0);
        }
      });
    });

    _updateStats();
  }

  void _updateStats() {
    final stats = cache.statistics;
    setState(() {
      cacheStats = '''
Cache Statistics:
  Hit Rate: ${(stats.hitRate * 100).toStringAsFixed(1)}%
  Hits: ${stats.hits}
  Misses: ${stats.misses}
  Evictions: ${stats.evictions}
  Entries: ${stats.entryCount}
  Size: ${(stats.totalSize / 1024).toStringAsFixed(1)}KB
''';
    });
  }

  Future<Map<String, dynamic>> _fetchUserData(int userId) async {
    // Simulate API call
    await Future.delayed(Duration(milliseconds: 500));

    // Simulate network request
    final response = await http.get(
      Uri.parse('https://jsonplaceholder.typicode.com/users/$userId'),
    );

    if (response.statusCode == 200) {
      return jsonDecode(response.body) as Map<String, dynamic>;
    } else {
      throw Exception('Failed to load user data');
    }
  }

  Future<void> _loadUserData(int userId) async {
    try {
      final userData = await cache.get(
        'user_$userId',
        () => _fetchUserData(userId),
        ttl: Duration(minutes: 10),
      );

      setState(() {
        currentData = jsonEncode(userData);
      });
      _updateStats();
    } catch (e) {
      setState(() {
        currentData = 'Error: $e';
      });
    }
  }

  Future<void> _forceRefreshUserData(int userId) async {
    try {
      final userData = await cache.get(
        'user_$userId',
        () => _fetchUserData(userId),
        forceRefresh: true,
      );

      setState(() {
        currentData = 'Refreshed: ${jsonEncode(userData)}';
      });
      _updateStats();
    } catch (e) {
      setState(() {
        currentData = 'Error: $e';
      });
    }
  }

  Future<void> _clearCache() async {
    await cache.clear();
    setState(() {
      currentData = 'Cache cleared';
    });
    _updateStats();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Flutter Async Cache Example'),
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
      ),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            Card(
              child: Padding(
                padding: const EdgeInsets.all(16.0),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    const Text(
                      'Cache Actions',
                      style:
                          TextStyle(fontSize: 18, fontWeight: FontWeight.bold),
                    ),
                    const SizedBox(height: 16),
                    Row(
                      children: [
                        Expanded(
                          child: ElevatedButton(
                            onPressed: () => _loadUserData(1),
                            child: const Text('Load User 1'),
                          ),
                        ),
                        const SizedBox(width: 8),
                        Expanded(
                          child: ElevatedButton(
                            onPressed: () => _loadUserData(2),
                            child: const Text('Load User 2'),
                          ),
                        ),
                      ],
                    ),
                    const SizedBox(height: 8),
                    Row(
                      children: [
                        Expanded(
                          child: ElevatedButton(
                            onPressed: () => _forceRefreshUserData(1),
                            child: const Text('Force Refresh'),
                          ),
                        ),
                        const SizedBox(width: 8),
                        Expanded(
                          child: ElevatedButton(
                            onPressed: _clearCache,
                            child: const Text('Clear Cache'),
                          ),
                        ),
                      ],
                    ),
                  ],
                ),
              ),
            ),
            const SizedBox(height: 16),
            Card(
              child: Padding(
                padding: const EdgeInsets.all(16.0),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    const Text(
                      'Current Data',
                      style:
                          TextStyle(fontSize: 18, fontWeight: FontWeight.bold),
                    ),
                    const SizedBox(height: 8),
                    Container(
                      padding: const EdgeInsets.all(8),
                      decoration: BoxDecoration(
                        color: Colors.grey[100],
                        borderRadius: BorderRadius.circular(4),
                      ),
                      child: Text(
                        currentData,
                        style: const TextStyle(fontFamily: 'monospace'),
                      ),
                    ),
                  ],
                ),
              ),
            ),
            const SizedBox(height: 16),
            Card(
              child: Padding(
                padding: const EdgeInsets.all(16.0),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    const Text(
                      'Cache Statistics',
                      style:
                          TextStyle(fontSize: 18, fontWeight: FontWeight.bold),
                    ),
                    const SizedBox(height: 8),
                    Text(
                      cacheStats,
                      style: const TextStyle(fontFamily: 'monospace'),
                    ),
                  ],
                ),
              ),
            ),
            const SizedBox(height: 16),
            Card(
              child: Padding(
                padding: const EdgeInsets.all(16.0),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    const Text(
                      'Recent Events',
                      style:
                          TextStyle(fontSize: 18, fontWeight: FontWeight.bold),
                    ),
                    const SizedBox(height: 8),
                    Container(
                      height: 120,
                      decoration: BoxDecoration(
                        color: Colors.grey[100],
                        borderRadius: BorderRadius.circular(4),
                      ),
                      child: ListView.builder(
                        itemCount: events.length,
                        itemBuilder: (context, index) {
                          return Padding(
                            padding: const EdgeInsets.symmetric(vertical: 2),
                            child: Text(
                              events[events.length - 1 - index],
                              style: const TextStyle(fontSize: 12),
                            ),
                          );
                        },
                      ),
                    ),
                  ],
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }

  @override
  void dispose() {
    cache.dispose();
    super.dispose();
  }
}