flutter_p2p_plus 是一个用于在 Flutter 中实现点对点（P2P）通信的插件。它允许设备之间直接通信，而无需通过中央服务器。这对于需要在本地网络中直接交换数据的应用程序非常有用。

以下是使用 flutter_p2p_plus 插件的基本步骤：

1. 添加依赖

首先，你需要在 pubspec.yaml 文件中添加 flutter_p2p_plus 插件的依赖：

dependencies:
  flutter:
    sdk: flutter
  flutter_p2p_plus: ^0.0.1  # 请使用最新版本

然后运行 flutter pub get 来获取依赖。

2. 初始化插件

在你的 Dart 代码中，首先需要初始化 flutter_p2p_plus 插件：

import 'package:flutter_p2p_plus/flutter_p2p_plus.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await FlutterP2pPlus.initialize();
  runApp(MyApp());
}

3. 发现设备

使用 flutter_p2p_plus 插件，你可以发现附近的设备。以下是一个简单的示例：

void discoverPeers() async {
  try {
    List<Peer> peers = await FlutterP2pPlus.discoverPeers();
    for (var peer in peers) {
      print('Discovered peer: ${peer.deviceName}');
    }
  } catch (e) {
    print('Failed to discover peers: $e');
  }
}

4. 连接到设备

发现设备后，你可以选择连接到某个设备：

void connectToPeer(Peer peer) async {
  try {
    await FlutterP2pPlus.connect(peer);
    print('Connected to ${peer.deviceName}');
  } catch (e) {
    print('Failed to connect to peer: $e');
  }
}

5. 发送和接收数据

连接成功后，你可以发送和接收数据。以下是一个简单的示例：

void sendMessage(String message) async {
  try {
    await FlutterP2pPlus.sendMessage(message);
    print('Message sent: $message');
  } catch (e) {
    print('Failed to send message: $e');
  }
}

void receiveMessage() async {
  try {
    String message = await FlutterP2pPlus.receiveMessage();
    print('Message received: $message');
  } catch (e) {
    print('Failed to receive message: $e');
  }
}

6. 断开连接

当你不再需要与设备通信时，可以断开连接：

void disconnect() async {
  try {
    await FlutterP2pPlus.disconnect();
    print('Disconnected from peer');
  } catch (e) {
    print('Failed to disconnect: $e');
  }
}

7. 处理权限

在使用 flutter_p2p_plus 插件时，确保你已经在 AndroidManifest.xml 和 Info.plist 中请求了必要的权限。

Android

在 AndroidManifest.xml 中添加以下权限：

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.INTERNET" />

iOS

在 Info.plist 中添加以下权限：

<key>NSBonjourServices</key>
<array>
    <string>_flutterp2p._tcp</string>
</array>
<key>NSLocalNetworkUsageDescription</key>
<string>We need access to the local network to discover and connect to other devices.</string>

8. 完整示例

以下是一个完整的示例，展示了如何使用 flutter_p2p_plus 插件进行点对点通信：

import 'package:flutter/material.dart';
import 'package:flutter_p2p_plus/flutter_p2p_plus.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await FlutterP2pPlus.initialize();
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      home: P2PExample(),
    );
  }
}

class P2PExample extends StatefulWidget {
  [@override](/user/override)
  _P2PExampleState createState() => _P2PExampleState();
}

class _P2PExampleState extends State<P2PExample> {
  List<Peer> peers = [];
  Peer? connectedPeer;

  void discoverPeers() async {
    try {
      List<Peer> discoveredPeers = await FlutterP2pPlus.discoverPeers();
      setState(() {
        peers = discoveredPeers;
      });
    } catch (e) {
      print('Failed to discover peers: $e');
    }
  }

  void connectToPeer(Peer peer) async {
    try {
      await FlutterP2pPlus.connect(peer);
      setState(() {
        connectedPeer = peer;
      });
      print('Connected to ${peer.deviceName}');
    } catch (e) {
      print('Failed to connect to peer: $e');
    }
  }

  void sendMessage(String message) async {
    try {
      await FlutterP2pPlus.sendMessage(message);
      print('Message sent: $message');
    } catch (e) {
      print('Failed to send message: $e');
    }
  }

  void receiveMessage() async {
    try {
      String message = await FlutterP2pPlus.receiveMessage();
      print('Message received: $message');
    } catch (e) {
      print('Failed to receive message: $e');
    }
  }

  void disconnect() async {
    try {
      await FlutterP2pPlus.disconnect();
      setState(() {
        connectedPeer = null;
      });
      print('Disconnected from peer');
    } catch (e) {
      print('Failed to disconnect: $e');
    }
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Flutter P2P Example'),
      ),
      body: Column(
        children: [
          ElevatedButton(
            onPressed: discoverPeers,
            child: Text('Discover Peers'),
          ),
          Expanded(
            child: ListView.builder(
              itemCount: peers.length,
              itemBuilder: (context, index) {
                return ListTile(
                  title: Text(peers[index].deviceName),
                  onTap: () => connectToPeer(peers[index]),
                );
              },
            ),
          ),
          if (connectedPeer != null) ...[
            ElevatedButton(
              onPressed: () => sendMessage('Hello, ${connectedPeer!.deviceName}!'),
              child: Text('Send Message'),
            ),
            ElevatedButton(
              onPressed: receiveMessage,
              child: Text('Receive Message'),
            ),
            ElevatedButton(
              onPressed: disconnect,
              child: Text('Disconnect'),
            ),
          ],
        ],
      ),
    );
  }
}