Question

我是Android开发的新手，我希望我的应用程序能够检测套接字事件，即使应用程序未通过后台服务处于活动状态（因此我可以执行推送通知，例如，如果有一个套接字事件触发的新消息Whatsapp和其他人如何做到这一点）。

我实现了后台服务和一个启动服务的应用程序类，但是在后台服务中将套接字事件作为Runnable任务放在哪里以及如何放置。

我修改了下面的socket.io android chat项目示例并添加了服务和应用程序类。

ChatApplication.java

package com.github.nkzawa.socketio.androidchat;

import android.app.Application;
import android.content.Intent;
import android.content.res.Configuration;

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

import java.net.URISyntaxException;

public class ChatApplication extends Application {

    @Override
    // called when the application is starting, before any other application objects have been created
    public void onCreate() {
        super.onCreate();

        // represents our background service
        Intent background = new Intent(this, SocketBackgroundService.class);
        startService(background);
    }

    private Socket mSocket;
    {
        try {
            mSocket = IO.socket(Constants.CHAT_SERVER_URL);
        } catch (URISyntaxException e) {
            throw new RuntimeException(e);
        }
    }

    public Socket getSocket() {
        return mSocket;
    }
}

SocketBackgroundService.java

package com.github.nkzawa.socketio.androidchat;

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.util.Log;

public class SocketBackgroundService extends Service {
    private boolean isRunning;
    private Thread backgroundThread;

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onCreate() {
        this.isRunning = false;
        this.backgroundThread = new Thread(myTask);
    }

    private Runnable myTask = new Runnable() {
        @Override
        public void run() {
            // do something in here
            Log.i("INFO", "SOCKET BACKGROUND SERVICE IS RUNNING");

            //TODO - how to handle socket events here?
            //How do I do something like mSocket.on(Socket.EVENT_CONNECT,onConnect); here?
        }
    };

    @Override
    public void onDestroy() {
        this.isRunning = false;
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        if( !this.isRunning) {
            this.isRunning = true;
            this.backgroundThread.start();
        }

        return START_STICKY;
    }
}

Answer 1

如果您的应用程序停止后仍需要套接字。将套接字移动到后台服务，然后您可以在服务中添加套接字事件。

Answer 2

您在主线程上打开套接字。不要在主线程上打开套接字连接，它会给你ANR（应用程序没有响应）错误，这是由于UI线程上的大量繁重工作而发生的。它会阻止UI线程超过5秒。所以我建议你在服务中的线程上打开套接字连接以下是使用普通套接字的示例：

为后台服务启动线程创建一个服务类
在Thread类上创建以在线程上打开套接字连接

为套接字通信创建单独的类

public class SocketBackgroundService extends Service {

private SocketThread mSocketThread;

@Override
public IBinder onBind(Intent intent) {
    return null;
}

@Override
public void onCreate() {

    mSocketThread = SocketThread.getInstance();
}


@Override
public void onDestroy() {
    //stop thread and socket connection here
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    if (mSocketThread.startThread) {
    } else {
        stopSelf();
    }

    return START_STICKY;
}
}

public class SocketThread extends Thread {

private static SocketThread mSocketThread;
private SocketClient mSocketClient;

private SocketThread() {
}

// create single instance of socket thread class
public static SocketThread getInstance() {
    if (mSocketThread == null)//you can use synchronized also
    {
        mSocketThread = new SocketThread();
    }
    return mSocketThread;
}


public boolean startThread() {
            =new SocketClient();
    if (socketClient.isConnected()) {
        mSocketThread.start()
        return true;
    }
    return false;
}

@Override
public void run() {
    super.run();
    while (mSocketClient.isConnected()) {
        // continue listen
    }
    // otherwise remove socketClient instance and stop thread
}

public class SocketClient {
    //write all code here regarding opening, closing sockets
    //create constructor
    public SocketClient() {
        // open socket connection here
    }

    public boolean isConnected() {
        return true;
    }
}

如何在Android中将套接字事件作为后台服务来处理？

2 个答案: