android - 如何在后台保持任务？

Question

我在我的 android 应用程序中使用 socket.io。我想保持连接，永远不要关闭，即使关闭应用程序也是如此。我创建了一个这样的服务类:

public class MyService extends Service {


private static Socket socket;
{
    try {
        socket = IO.socket("http://192.168.1.52:2500");
    } catch (URISyntaxException e) {
        throw new RuntimeException(e);
    }
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {

    socket.connect();
    return Service.START_STICKY;
}

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

在我的主类中使用这段代码:

    Intent intent = new Intent(this,MyService.class);
    startService(intent);

但是Socket连接不上!

Answer 1

您必须运行 Service 才能保持连接有效。

public class MyService extends Service {

  @Override
  public int onStartCommand(Intent intent, int flags, int startId) {

      connectSocket()

      return Service.START_STICKY;
  }

   private void connectSocket() {
    try {
        IO.Options options = new IO.Options();
        options.reconnection = true;

        socket = IO.socket("http://192.168.1.52:2500", options);
        socket.on(Socket.EVENT_CONNECT, onConnected);
        socket.on(Socket.EVENT_CONNECT_ERROR, onConnectionError);
        socket.on(Socket.EVENT_CONNECT_TIMEOUT, onConnectionTimout);
        socket.on(Socket.EVENT_DISCONNECT, onDisconnect);
        socket.on("Event_Key", eventCallback );
        socket.connect();
    } catch (URISyntaxException e) {
        Log.d(getClass().getSimpleName(), "Socket Connection Exception");
        e.printStackTrace();
    }

  private Emitter.Listener onConnected = new Emitter.Listener() {
    @Override
    public void call(Object... args) {
        Log.d("SocketIO","onConnected");
    }
  };

  private Emitter.Listener onConnectionError = new Emitter.Listener() {
    @Override
    public void call(Object... args) {
        Log.d("SocketIO","onConnectionError");
        if (!closeSocket)
            socket.connect();
    }
  };

  private Emitter.Listener onConnectionTimout = new Emitter.Listener() {
    @Override
    public void call(Object... args) {
        Log.d("SocketIO","onConnectionTimout");
        if (!closeSocket)
            socket.connect();
    }
  };

  private Emitter.Listener onDisconnect = new Emitter.Listener() {
    @Override
    public void call(Object... args) {
        Log.d("SocketIO","onDisconnect");
        if (!closeSocket)
            socket.connect();
    }
  };

  private Emitter.Listener eventCallback = new Emitter.Listener() {
    @Override
    public void call(Object... args) {
        Log.d("SocketIO", "Result: "+ String.valueOf(args[0]);
    }
};

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

服务将在 Backgourd 中运行，直到您停止它或系统停止它。

启动服务如下:

Intent intent = new Intent(this, MyService.class);
startService(intent);