Android 上的 Socket IO 连接失败

我正在尝试使用 Socket IO、Android 和 Node 创建一个简单的聊天。 当我运行应用程序并尝试连接到服务器时，它总是因超时错误而失败，我不明白为什么。

这是节点代码：

app = require('express')()
http = require('http').createServer(app)
io = require('socket.io')(http)

app.get('/', (req,res) => {

    res.send('Chat server is running on port 5000')
})

/**
 * Defines a listener to an event called connection and this event will be fired from the client side
 */
io.on('connection', (socket) => {

    console.log('user connected')
})

http.listen(5000, () => {

    console.log('Node app is running on port 5000')
})

这是 Android 代码（根据 Marcos Casagrande 回答编辑:

import com.github.nkzawa.socketio.client.IO;
import com.github.nkzawa.socketio.client.Socket;
import com.github.nkzawa.engineio.client.transports.WebSocket;

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_chat);

    Intent intent = getIntent();
    if(intent.hasExtra(NICKNAME)){

        mNickname = intent.getStringExtra(NICKNAME);
        Log.d(TAG, "chatapp onCreate: " + mNickname);
    }

    try {

        IO.Options opts = new IO.Options();
        opts.transports = new String[]{WebSocket.NAME};
        mSocket = IO.socket("http://10.0.0.21:5000", opts);

        mSocket.on(Socket.EVENT_CONNECT, new Emitter.Listener() {
            @Override
            public void call(Object... args) {
                Log.d(TAG, "chatapp call: connected to server");
            }
        });

        mSocket.on(Socket.EVENT_DISCONNECT, new Emitter.Listener() {
            @Override
            public void call(Object... args) {
                Log.d(TAG, " chatapp call: disconnected from the server");
            }
        });

        mSocket.on(Socket.EVENT_CONNECT_ERROR, new Emitter.Listener() {
            @Override
            public void call(Object... args) {
                Log.d(TAG, "chatapp call: connection error");
            }
        });

        mSocket.on(Socket.EVENT_CONNECT_TIMEOUT, new Emitter.Listener() {
            @Override
            public void call(Object... args) {
                Log.d(TAG, "chatapp call: connection timeout");
            }
        });

        mSocket.connect();

    } catch (Exception e) {
        Log.d(TAG, "onCreate: something unexpected happened");
        e.printStackTrace();
    }

我尝试通过 Android Studio 在虚拟设备上运行该应用程序，但我不断收到连接超时错误。有人可以告诉我，我做错了什么吗？

连接不会立即发生，它是异步的，附加正确的处理程序 https://github.com/socketio/socket.io-client-java#usage并检查其中的连接或错误。

mSocket = IO.socket("http://localhost:5000");

mSocket.on(Socket.EVENT_CONNECT, onConnect);
mSocket.on(Socket.EVENT_DISCONNECT, onDisconnect);
mSocket.on(Socket.EVENT_CONNECT_ERROR, onConnectError);
mSocket.on(Socket.EVENT_CONNECT_TIMEOUT, onConnectError);

mSocket.connect();
// ....

private Emitter.Listener onConnect = new Emitter.Listener() {
    @Override
    public void call(Object... args) {
        Log.d(TAG, "connected...");
        // This doesn't run in the UI thread, so use: 
        // .runOnUiThread if you want to do something in the UI

    }
};

private Emitter.Listener onConnectError = new Emitter.Listener() {
    @Override
    public void call(Object... args) {
        Log.d(TAG, "Error connecting...");
    }
};

我建议在android中使用WebSocket传输，以避免轮询错误，你可以在这里查看我的答案：

如何在 Android 中设置 SocketIO 的传输？ https://stackoverflow.com/questions/44015305/how-to-set-transports-for-socketio-in-android/44023957#44023957