问题可能出在服务器配置上。

Android 7.0有一个bug。Vicky Chijwani提出的解决方案:

配置您的服务器以使用椭圆曲线prime256v1。为 例如，在Nginx 1.10中，你可以通过设置ssl_ecdh_curve来实现 prime256v1;

这里的问题是iOS默认不允许HTTP请求，只允许HTTPS。如果你想启用HTTP请求，添加到你的info.plist:

<key>NSAppTransportSecurity</key>
<dict>
    <key>NSAllowsArbitraryLoads</key>
    <true/>
</dict>

对于Android设备，进入您的项目根文件夹并运行命令:

adb reverse tcp:[your_own_server_port] tcp:[your_own_server_port]

例如:adb reverse tcp:8088 tcp:8088

这将使您的物理设备(即。Android手机)监听本地主机服务器运行在您的开发机器(即您的计算机)地址http://localhost:[your_own_server_port]。

之后，你可以直接在react-native fetch()调用中使用http:localhost:[your_port] /your_api。

如果你使用localhost，只需更改它:

来自:http://localhost: 3030 : http://10.0.2.2:3030

修复TypeError:在Android调试版本中将文件上传到http而不是https时网络请求失败

在react-native 0.63.2(我正在测试)或更高版本中，如果只是使用fetch将文件上传到http(而不是https)服务器，将会遇到TypeError:网络请求失败。

在这里，我使用axios@0.27.2作为运行在Android手机上的客户端，成功地将文件上传到react-native-file-server作为运行在另一台Android手机上的服务器。

客户端需要编辑JAVA和JS代码，服务器不需要编辑JAVA代码。

在调试构建中，必须注释掉这个文件android/app/src/debug/java/com/YOUR_PACKAGE_NAME/ReactNativeFlipper.java中的43行

38      NetworkFlipperPlugin networkFlipperPlugin = new NetworkFlipperPlugin();
39      NetworkingModule.setCustomClientBuilder(
40          new NetworkingModule.CustomClientBuilder() {
41            @Override
42            public void apply(OkHttpClient.Builder builder) {
43      //        builder.addNetworkInterceptor(new FlipperOkhttpInterceptor(networkFlipperPlugin));
44            }
45          });
46      client.addPlugin(networkFlipperPlugin);

也许还需要添加android:usesCleartextTraffic="true"下的<应用程序的android/app/src/main/AndroidManifest.xml，在我的测试，这是不必要的调试和发布构建。

  onFileSelected = async (file) => {
    // API ref to the server side BE code `addWebServerFilter("/api/uploadtodir", new WebServerFilter()`
    // https://github.com/flyskywhy/react-native-file-server/blob/1034a33dd6d8b0999705927ad78368ca1a639add/android/src/main/java/webserver/WebServer.java#L356
    // could not be 'localhost' but IP address
    const serverUploadApi = 'http://192.168.1.123:8080/api/uploadtodir';

    // the folder on server where file will be uploaded to, could be e.g. '/storage/emulated/0/Download'
    const serverFolder = '/storage/emulated/0/FileServerUpload';

    const fileToUpload = {
      // if want to upload and rename, it can be `name: 'foo.bar'`, but can not be 'foo'
      // only if your server upload code support file name without type, on our server
      // https://github.com/flyskywhy/react-native-file-server/blob/1034a33dd6d8b0999705927ad78368ca1a639add/android/src/main/java/webserver/WebServer.java#L372
      // will cause java.lang.StringIndexOutOfBoundsException in substring()
      name: file.name,

      // type is necessary in Android, it can be 'image/jpeg' or 'foo/bar', but can not be
      // 'foo', 'foo/', '/foo' or undefined, otherwise will cause `[AxiosError: Network Error]`
      type: 'a/b',

      uri: Platform.OS === 'android' ? file.uri : file.uri.replace('file://', ''),
    };

    const form = new FormData();
    form.append('path', serverFolder);
    form.append('uploadfile', fileToUpload);

    // ref to the server side FE code `this.axios.post("/api/uploadtodir", parms, config)`
    // https://github.com/flyskywhy/react-native-file-server/blob/1034a33dd6d8b0999705927ad78368ca1a639add/fileserverwebdoc/src/views/Manage.vue#L411
    let res = await axios.post(serverUploadApi, form, {
      headers: {
        'Content-Type': 'multipart/form-data',
      },
      onUploadProgress: function (progressEvent) {
        console.warn(progressEvent);
      },
    });

    // ref to the server side BE code `return newFixedLengthResponse("Suss");`
    // https://github.com/flyskywhy/react-native-file-server/blob/1034a33dd6d8b0999705927ad78368ca1a639add/android/src/main/java/webserver/WebServer.java#L380
    if (res.data === 'Suss') {
      console.warn('Upload Successful');
    } else if (res.data === 'fail') {
      console.warn('Upload Failed');
    }
  };

只需添加

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

    <application
      android:usesCleartextTraffic="true"

然后将获取URL域(localhost)替换为您的IP地址，

const dataRaw = await fetch('http://192.168.8.102:4000');