Flutter网络连接检测插件flutter_network_connectivity的使用
Flutter网络连接检测插件flutter_network_connectivity的使用
插件简介
Flutter Network Connectivity
是一个用于检查互联网可用性的Flutter插件。它基于网络连接状态、定期间隔或按需调用来提供服务。该插件支持通过流的方式监听网络变化,也可以即时查询当前网络状态。
安装与配置
添加依赖
首先,在你的 pubspec.yaml
文件中添加 flutter_network_connectivity
作为依赖项:
dependencies:
flutter_network_connectivity: ^0.0.6
然后执行 flutter pub get
来获取并安装新添加的包。
导入库
在需要使用的Dart文件顶部导入插件:
import 'package:flutter_network_connectivity/flutter_network_connectivity.dart';
使用方法
创建实例
创建一个 FlutterNetworkConnectivity
对象,并根据需求设置参数:
FlutterNetworkConnectivity flutterNetworkConnectivity = FlutterNetworkConnectivity(
isContinousLookUp: true, // 是否持续检测,默认为true
lookUpDuration: const Duration(seconds: 5), // 检测间隔时间,默认为5秒
lookUpUrl: 'example.com', // 用于检测的URL,默认为'example.com'
);
监听网络状态变化(流)
为了实时监控网络状态的变化,可以订阅插件提供的流:
_flutterNetworkConnectivity.getInternetAvailabilityStream().listen((isInternetAvailable) {
// 当网络状态发生变化时,这里会接收到最新的状态
});
注册和注销监听器:
await _flutterNetworkConnectivity.registerAvailabilityListener();
// ...
await _flutterNetworkConnectivity.unregisterAvailabilityListener();
即时查询网络状态
如果你只需要在特定时刻检查一次网络是否可用,可以调用以下方法:
bool _isNetworkConnectedOnCall = await
_flutterNetworkConnectivity.isInternetConnectionAvailable();
示例代码
下面是一个完整的示例程序,展示了如何将上述功能集成到一个简单的Flutter应用中:
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_network_connectivity/flutter_network_connectivity.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatefulWidget {
const MyApp({Key? key}) : super(key: key);
@override
State<MyApp> createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
final FlutterNetworkConnectivity _flutterNetworkConnectivity =
FlutterNetworkConnectivity(
isContinousLookUp: true,
lookUpDuration: const Duration(seconds: 5),
lookUpUrl: 'example.com',
);
bool? _isInternetAvailableOnCall;
bool? _isInternetAvailableStreamStatus;
StreamSubscription<bool>? _networkConnectionStream;
@override
void initState() {
super.initState();
_flutterNetworkConnectivity.getInternetAvailabilityStream().listen((event) {
_isInternetAvailableStreamStatus = event;
setState(() {});
});
init();
}
@override
void dispose() async {
_networkConnectionStream?.cancel();
_flutterNetworkConnectivity.unregisterAvailabilityListener();
super.dispose();
}
void init() async {
await _flutterNetworkConnectivity.registerAvailabilityListener();
}
Future<void> _checkInternetAvailability() async {
try {
_isInternetAvailableOnCall =
await _flutterNetworkConnectivity.isInternetConnectionAvailable();
} on PlatformException {
_isInternetAvailableOnCall = null;
}
if (!mounted) return;
setState(() {});
}
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: const Text('Flutter Network Connectivity'),
),
body: Column(
children: [
Expanded(
child: Container(
color: Colors.black12,
child: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
const SizedBox(height: 24.0),
const Text(
'Internet Availability Stream',
style: TextStyle(fontSize: 16.0),
textAlign: TextAlign.center,
),
Expanded(
child: Center(
child: Text(
null == _isInternetAvailableStreamStatus
? 'Unknown State'
: _isInternetAvailableStreamStatus!
? "You're Connected to Network"
: "You're Offline",
style: const TextStyle(fontSize: 18.0, fontWeight: FontWeight.w600),
),
),
),
],
),
),
),
),
Expanded(
child: Container(
color: Colors.lightGreen.shade400,
child: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
const SizedBox(height: 24.0),
const Text(
'Internet Availability Status on Call',
style: TextStyle(fontSize: 16.0),
),
Expanded(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Text(
null == _isInternetAvailableOnCall
? 'Unknown State'
: _isInternetAvailableOnCall!
? "You're Connected to Network"
: "You're Offline",
style: const TextStyle(fontSize: 18.0, fontWeight: FontWeight.w600),
),
const SizedBox(height: 50.0),
ElevatedButton(
onPressed: _checkInternetAvailability,
style: ElevatedButton.styleFrom(primary: Colors.amberAccent),
child: const Text(
'Check Network State',
style: TextStyle(color: Colors.black),
),
),
],
),
),
],
),
),
),
),
],
),
),
);
}
}
此示例展示了如何使用 flutter_network_connectivity
插件来监测网络连接状态,并根据不同的场景显示相应的提示信息。用户可以通过点击按钮手动检查当前的网络状况,同时也能看到自动更新的网络状态变化。
更多关于Flutter网络连接检测插件flutter_network_connectivity的使用的实战系列教程也可以访问 https://www.itying.com/category-92-b0.html
更多关于Flutter网络连接检测插件flutter_network_connectivity的使用的实战系列教程也可以访问 https://www.itying.com/category-92-b0.html
当然,以下是如何在Flutter项目中使用flutter_network_connectivity
插件来检测网络连接的代码示例。
1. 添加依赖
首先,你需要在pubspec.yaml
文件中添加flutter_network_connectivity
依赖:
dependencies:
flutter:
sdk: flutter
flutter_network_connectivity: ^3.0.0 # 请检查最新版本号
2. 导入包
在你的Dart文件中,导入flutter_network_connectivity
包:
import 'package:flutter_network_connectivity/flutter_network_connectivity.dart';
3. 初始化插件
在你的主文件(例如main.dart
)中,初始化插件并监听网络连接状态的变化:
import 'package:flutter/material.dart';
import 'package:flutter_network_connectivity/flutter_network_connectivity.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Network Connectivity Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: ConnectivityChecker(),
);
}
}
class ConnectivityChecker extends StatefulWidget {
@override
_ConnectivityCheckerState createState() => _ConnectivityCheckerState();
}
class _ConnectivityCheckerState extends State<ConnectivityChecker> {
final Connectivity _connectivity = Connectivity();
String _connectionStatus = 'Unknown';
@override
void initState() {
super.initState();
initConnectivity();
_connectivity.onConnectivityChanged.listen((ConnectivityResult result) {
setState(() {
_connectionStatus = result.toString();
});
});
}
Future<void> initConnectivity() async {
ConnectivityResult result = await _connectivity.checkConnectivity();
setState(() {
_connectionStatus = result.toString();
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Network Connectivity Status'),
),
body: Center(
child: Text(
'Connection Status: $_connectionStatus',
style: TextStyle(fontSize: 24),
),
),
);
}
}
4. 运行应用
确保你已经连接了设备或启动了模拟器,然后运行flutter run
来启动你的应用。
解释
- 依赖添加:在
pubspec.yaml
中添加flutter_network_connectivity
依赖。 - 包导入:在需要检测网络连接的Dart文件中导入
flutter_network_connectivity
包。 - 初始化插件:在
initState
方法中调用initConnectivity
方法来获取当前的网络连接状态,并设置监听器来监听网络连接状态的变化。 - UI更新:使用
setState
方法来更新UI,以显示当前的网络连接状态。
这样,你的Flutter应用就可以实时检测并显示网络连接状态了。