问题详情： flutter 组件未进行特殊设置的情况下不会走代理，无法被抓包；

解决方案：

（1）在 dio 网络请求组件中设置代理的 ip 地址和 port，强制使用代理请求网络；

    class ProxyUtils {
      // 是否启用代理
      static bool PROXY_ENABLE = false;
      /// 代理服务IP
      static String PROXY_IP = '172.0.0.1';
      /// 代理服务端口
      static int PROXY_PORT = 8888;  
    }

    // 在调试模式下需要抓包调试，所以我们使用代理，并禁用HTTPS证书校验
    if (ProxyUtils.PROXY_ENABLE) {
      (dio.httpClientAdapter as DefaultHttpClientAdapter).onHttpClientCreate =
          (client) {
        client.findProxy = (uri) {
          var ip = ProxyUtils.PROXY_IP;
          var port = ProxyUtils.PROXY_PORT;
          return "PROXY $ip:$port";
        };
        // 代理工具会提供一个抓包的自签名证书，会通不过证书校验，所以我们禁用证书校验
        client.badCertificateCallback =
            (X509Certificate cert, String host, int port) => true;
      };
    }

（2）ip 和 port 肯定不能通过硬编码的方式写在代码中，所以我们通过路由传值的方式将 port 和 ip 从原生传到 flutter 组件；

获取当前代理 ip 和 port （iOS）：

// 自动获取手机代理
NSString *portalBaseUrlStr = @"http://www.baidu.com";
NSDictionary *proxySettings = (__bridge NSDictionary *)(CFNetworkCopySystemProxySettings());
NSArray *proxies = (__bridge NSArray *)(CFNetworkCopyProxiesForURL((__bridge CFURLRef _Nonnull)([NSURL URLWithString:portalBaseUrlStr]), (__bridge CFDictionaryRef _Nonnull)(proxySettings)));
NSDictionary *settings = [proxies firstObject];
NSString *hostName = [NSString stringWithFormat:@"%@",settings[@"kCFProxyHostNameKey"]];
NSString *portName = [NSString stringWithFormat:@"%@",settings[@"kCFProxyPortNumberKey"]];
// 获取为空时居然是字符串"(null)"
if ([hostName isEqualToString:@"(null)"]) {
    hostName = @"";
}
if ([portName isEqualToString:@"(null)"]) {
    portName = @"";
}
NSString *proxy_ip = hostName;
NSString *proxy_port = portName;
通过路由传递 ip 和 port（iOS）:

FlutterEngine *flutterEngine = [[FlutterEngine alloc] initWithName:@"io.flutter" project:nil];
        
if ([SystemInfoUtils isProxy]) {
    NSString *route = [NSString stringWithFormat:@"wallpaper?port=%@&ip=%@", [SystemInfoUtils proxy_port],[SystemInfoUtils proxy_ip]];
    [self.flutterEngine runWithEntrypoint:nil initialRoute:route];
} else {
    [self.flutterEngine runWithEntrypoint:nil];
}

flutter 接收 ip 和 port 参数：

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        primaryColor: Colors.white,
      ),
      home: _route(window.defaultRouteName),
      builder: EasyLoading.init(),
    );
  }
}

Widget _route(String url) {
  // 解析路由参数
  Uri u = Uri.parse(url);
  Map<String, String> qp = u.queryParameters;

  final port = qp["port"];
  final ip = qp["ip"];

  if (port != null && ip != null) {
    ProxyUtils.PROXY_ENABLE = true;
    ProxyUtils.PROXY_IP = ip;
    ProxyUtils.PROXY_PORT = int.parse(port);

    print("Flutter config proxy ip is $ip port is $port");
  }

  //跳转页面
  switch (u.path) {
    case 'wallpaper':
      return WallpaperViewController();
    default:
      return WallpaperViewController();
  }
}