android app socket.io未连接到node.js服务器，但android浏览器建立了连接

Question

I have setup node.js server running on port 3000. Connections from my laptop browser are successful and I can see the result in the console log.

In my android client I used nkzawa's Socket.io library, but it's not establishing connection with the server, where as when I try to open the http://ipaddr:PORT , in my android browser, connection is successful.

To be sure, I used ngrok to create a public DNS for my localhost:PORT. When i use ngrok's public DNS for Socket connection, android throws an error saying Internet permission denied and unable to resolve hostname. (Is it because of redirects?) but that address works fine on laptop and mobile browser.

I am completely stuck here. Android Socket.io is not connecting to server. I am following this tutorial . What am I missing?

Server:

 var express = require('express');
 var app = express();
 var server = require('http').createServer(app);
 var io = require('socket.io').listen(server);  


 connections =[];

 server.listen(3000);
 console.log("server running ...");

 app.get('/', function(req, res){
    res.sendFile(__dirname + '/index.html');
 });

 io.sockets.on('connection', function(socket) {
    connections.push(socket);
    console.log("new connection");
    console.log('connected: %s sockets', connections.length);

    // Disconeect
    socket.on('disconnect', function(data){
        connections.splice(connections.indexOf(socket),1);
        console.log('Disconnection');
        console.log('connected: %s sockets', connections.length);
    }); 

  });

Android Client:

import io.socket.client.IO;
import io.socket.client.Socket;


public class MainActivity extends AppCompatActivity {
    private  static  final String TAG = "MainActivity" ;
    private Socket mSocket;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        try{
            Log.i(TAG, "Attempting socket connection");
            mSocket = IO.socket("http://10.10.11.44:3000/");
        }
        catch (URISyntaxException e){
            Toast.makeText(getApplicationContext(),"Not connected",Toast.LENGTH_LONG).show();
            Log.i(TAG, "ERROR : Socket connection failed");
            throw new RuntimeException();
        }

        mSocket.connect();
        if(mSocket.connected()){
            Log.i(TAG, "Socket connection successful");
        }
        else{
            Log.i(TAG, "Socket connection failed");
        }

    }
  .
  .
  .

Android client Manifest:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.batmanlost.chatapp" >

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

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Answer 1

可能为时已晚，无法答复，但是您可以在Android应用中将“ http://10.10.11.44:3000/ ”替换为“ http：// ipaddr：3000 ”。

Answer 2

如果您使用仿真器进行测试，则使用本地主机地址作为“ http://10.0.2.2:3000 ”；如果您使用移动设备进行测试，则需要将手机连接到与您使用相同的网络PC /笔记本电脑已连接，然后使用上面给出的相同地址进行连接。