android 屏幕关闭时无法保持套接字连接

Question

我在 android 中保持套接字连接时遇到问题。

我在我的应用程序中使用Socket.IO-client java 库。

当屏幕打开时，套接字连接保持不变。

但是，如果屏幕关闭，则套接字会因 ping 超时而断开连接。

我怎么解决这个问题？

我像这样打开连接。

private static final String EVENT_CONNECT = Socket.EVENT_CONNECT;
private static final String EVENT_MESSAGE = Socket.EVENT_MESSAGE;
private static final String EVENT_DISCONNECT = Socket.EVENT_DISCONNECT;
private static final String EVENT_PING = Socket.EVENT_PING;
private static final String EVENT_CONNECT_TIMEOUT = Socket.EVENT_CONNECT_TIMEOUT;
private static final String EVENT_ERROR = Socket.EVENT_ERROR;

public void connect() {
    if (socket != null && socket.connected() == true) {
        return;
    }
    IO.Options options = new IO.Options();

    options.timeout = 60 * 1000;
    options.reconnection = true;

    Log.d(TAG, "try socket connect");
    socket.on(EVENT_CONNECT, this::onConnected)
            .on(EVENT_MESSAGE, this::onMessage)
            .on(EVENT_DISCONNECT, this::onDisconnected)
            .on(EVENT_PING, this::onPing)
            .on(EVENT_CONNECT_TIMEOUT, this::onConnectTimeout)
            .on(EVENT_ERROR, this::onError);

    socket.connect();
}

这是我的服务器端代码

var Socket = require('socket.io');
var io = Socket(server, { 'pingInterval': 25 * 1000 });
var port = process.env.PORT || 3000;

io.on('connection', function(socket){
    console.log('a user connected');

    ...

    socket.on('disconnect', function(data){
        (typeof socket.member != 'undefined') && disconnect(socket);
        console.log(data);
    });
});

ping 间隔为 25 秒，超时为 60 秒。

当 Android 屏幕关闭时，客户端无法工作EVENT_PING。另一个事件正常工作。

服务器已断开连接并显示日志（ping 超时）。

Answer 1

我解决这个问题如下：

private static final String EVENT_PING = "ping1";
private static final String EVENT_PONG = "pong1";

public void connect() {
    if (socket != null && socket.connected() == true) {
        return;
    }
    IO.Options options = new IO.Options();

    options.timeout = 60 * 1000;
    options.reconnection = true;

    Log.d(TAG, "try socket connect");
    socket.on(EVENT_CONNECT, this::onConnected)
            .on(EVENT_MESSAGE, this::onMessage)
            .on(EVENT_DISCONNECT, this::onDisconnected)
            .on(EVENT_PING, this::onPing)
            .on(EVENT_CONNECT_TIMEOUT, this::onConnectTimeout)
            .on(EVENT_ERROR, this::onError);

    socket.connect();
}

private void onPing(Object... args) {
    Log.d(TAG, "socket ping");
    socket.emit(EVENT_PONG);
}

这是服务器代码。

var pingInterval = 25 * 1000;
var Socket = require('socket.io');
var io = Socket(server, { 'pingInterval': pingInterval });
var port = process.env.PORT || 3000;

io.on('connection', function(socket){
    console.log('a user connected');

    function sendPing() {
        socket.emit('ping1');
    }

    setTimeout(sendPing, pingInterval);

    socket.on('disconnect', function(data){
        (typeof socket.member != 'undefined') && disconnect(socket);
        console.log(data);
    });

    socket.on('pong1', function(data) {
        setTimeout(sendPing, pingInterval);
        console.log('pong');
    });
});