Flutter Android连接IoT Wi-Fi后HTTP请求报错errno=64求助

核心原因 #

Android系统的网络优先级策略会优先选择有互联网连接的网络，即使你通过WifiIOT切换到了IoT设备的WiFi，应用可能仍在尝试使用原有网络；另外，明文HTTP限制、未正确绑定网络也会触发这类错误。

具体解决方案 #

1. 绑定IoT WiFi网络到应用进程 #

Android 10及以上版本，系统不会自动让应用切换到无互联网的WiFi，需要手动将应用进程绑定到目标网络。

实现步骤：

• 在Android原生代码中添加网络绑定逻辑，通过MethodChannel让Flutter调用：

  // MainActivity.kt
  import android.net.ConnectivityManager
  import android.net.Network
  import android.net.NetworkCapabilities
  import android.net.NetworkRequest
  import io.flutter.embedding.android.FlutterActivity
  import io.flutter.embedding.engine.FlutterEngine
  import io.flutter.plugin.common.MethodChannel
  
  class MainActivity : FlutterActivity() {
      private val CHANNEL = "com.example.network/bind"
      private var connectivityManager: ConnectivityManager? = null
      private var networkCallback: ConnectivityManager.NetworkCallback? = null
  
      override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
          super.configureFlutterEngine(flutterEngine)
          connectivityManager = getSystemService(CONNECTIVITY_SERVICE) as ConnectivityManager
          MethodChannel(flutterEngine.dartExecutor.binaryMessenger, CHANNEL).setMethodCallHandler { call, result ->
              if (call.method == "bindToIoTNetwork") {
                  val ssid = call.argument<String>("ssid")
                  bindToNetwork(ssid, result)
              } else {
                  result.notImplemented()
              }
          }
      }
  
      private fun bindToNetwork(ssid: String?, result: MethodChannel.Result) {
          val networkRequest = NetworkRequest.Builder()
              .addTransportType(NetworkCapabilities.TRANSPORT_WIFI)
              .build()
  
          networkCallback = object : ConnectivityManager.NetworkCallback() {
              override fun onAvailable(network: Network) {
                  val capabilities = connectivityManager?.getNetworkCapabilities(network)
                  val wifiSsid = capabilities?.ssid?.removeSurrounding("\"")
                  if (wifiSsid == ssid) {
                      connectivityManager?.bindProcessToNetwork(network)
                      result.success("Successfully bound to network $ssid")
                      connectivityManager?.unregisterNetworkCallback(this)
                  }
              }
          }
          connectivityManager?.registerNetworkCallback(networkRequest, networkCallback!!)
      }
  
      override fun onDestroy() {
          super.onDestroy()
          networkCallback?.let { connectivityManager?.unregisterNetworkCallback(it) }
      }
  }
  

• 在Flutter中调用该方法（连接WiFi成功后）：

  import 'package:flutter/services.dart';
  
  final MethodChannel _channel = MethodChannel('com.example.network/bind');
  
  Future<void> bindToIoTNetwork(String ssid) async {
    try {
      await _channel.invokeMethod('bindToIoTNetwork', {'ssid': ssid});
    } on PlatformException catch (e) {
      print("Failed to bind network: ${e.message}");
    }
  }
  

2. 允许明文HTTP请求 #

IoT设备通常使用HTTP明文传输，Android 9+默认禁止，需配置允许：

• 快速配置：在AndroidManifest.xml的<application>标签中添加：

  android:usesCleartextTraffic="true"
  

• 更安全的针对性配置：创建res/xml/network_security_config.xml：

  <?xml version="1.0" encoding="utf-8"?>
  <network-security-config>
      <domain-config cleartextTrafficPermitted="true">
          <domain includeSubdomains="true">192.168.33.1</domain>
      </domain-config>
  </network-security-config>
  

  然后在AndroidManifest.xml的<application>标签引用：

  android:networkSecurityConfig="@xml/network_security_config"
  

3. 确保权限齐全 #

在AndroidManifest.xml中添加必要权限：

<uses-permission android:name="android.permission.INTERNET" />
<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_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> <!-- Android 12+ 扫描WiFi需要 -->

4. 等待网络完全就绪 #

WifiIOT的连接成功回调仅表示WiFi关联完成，需等待DHCP获取IP后再发起请求：

• 使用connectivity_plus插件监听网络状态，确认已连接到目标WiFi：

  import 'package:connectivity_plus/connectivity_plus.dart';
  
  Future<void> waitForNetworkReady() async {
    final connectivityResult = await Connectivity().checkConnectivity();
    if (connectivityResult == ConnectivityResult.wifi) {
      // 等待DHCP分配IP，可根据实际情况调整时长
      await Future.delayed(const Duration(seconds: 2));
    }
  }
  

5. 检查Dio客户端配置 #

确保Dio未设置代理，避免请求走错误的网络：

import 'package:dio/dio.dart';

final dio = Dio(BaseOptions(
  baseUrl: "http://192.168.33.1",
  proxy: null, // 明确禁用代理
));

// 发起请求
var result = await dio.get("/rpc/Webhook.ListSupported");

内容的提问来源于stack exchange，提问作者Nicolas HOAREAU