Question

首先，我知道这是一个非常普通的问题，我已经浏览了数十个出版物和帖子。他们的解决方案基本相同。但经过几个小时的尝试仍然不适合我。

问题在于发送/接收短信 - 我没有收到服务器的任何回复。它不是HTTP服务器所以我使用Socket。我想可能有几个原因：

连接初始化的问题;
可能发送/接收消息的过程是错误的;
Perhabs我正在构建messages by protocol某种错误。

现在代码。

初始化/打开套接字连接：

    private class OpenSocketTask extends AsyncTask<Void, Void, Void> {

    @Override
    protected Void doInBackground(Void... params) {
        try {
            // Creating InetAddress object from ipNumber passed via constructor from IpGetter class.
            InetAddress serverAddress = InetAddress.getByName(HOST); //also tried instead: socket = new Socket(HOST, PORT);

            // Create a new Socket instance and connect to host
            socket = new Socket(serverAddress, PORT);
            Log.i(TAG, "Socket created: " + HOST + ":" + PORT);

            // Create PrintWriter object for sending messages to server.
            // out = new PrintWriter(socket.getOutputStream(), true); //also tried this
            out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())), true);

            //Create BufferedReader object for receiving messages from server.
            in = new BufferedReader(new InputStreamReader(socket.getInputStream()));

            Log.d(TAG, "In/Out created");

        } catch (UnknownHostException e) {
            Log.e(TAG, "Don't know about host: " + HOST + ":" +PORT);
            connected = false;
            Log.e(TAG, e.getMessage());
        } catch (IOException e) {
            Log.e(TAG, "Couldn't get I/O for the connection to: " + HOST + ":" +PORT);
            connected = false;
            Log.e(TAG, e.getMessage());
        }
        connected = true;
        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        if (connected) {
            Log.d(TAG, "Connected to TCP server...");
        }
        super.onPostExecute(result);
    }
}

发送和接收消息：

    public class ServerSendMessageTask extends AsyncTask<Void, Void, Void> {
    private String message;

    public ServerSendMessageTask(String message){
        this.message = message;
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
    }

    @Override
    protected Void doInBackground(Void... params) {
        if (connected) {
            Log.d(TAG, "Sending command to server: " + message);
            try {
                out.println(message);
                out.flush();

                /**
                 * Alternative for SEND message
                 * Both didn't work.
                 * */
//                    //Send the message to the server
//                    OutputStream os = socket.getOutputStream();
//                    OutputStreamWriter osw = new OutputStreamWriter(os);
//                    BufferedWriter bw = new BufferedWriter(osw);
//                    bw.write(message);
//                    bw.flush();

                Log.d(TAG, "Message was sent: " + message);

                //Listen for the incoming messages while connected = true
                while (connected) {
                    String incomingMessage = in.readLine();
                    if (incomingMessage != null) {
                        //never reach here :(
                        Log.d(TAG, "Received from server string: " + incomingMessage);
                    }
                }

                /**
                 * This is the alternative way to RECEIVE message
                 * Both didn't work for me
                 * */
//                    //Get the return message from the server
//                    InputStream is = socket.getInputStream();
//                    InputStreamReader isr = new InputStreamReader(is);
//                    BufferedReader br = new BufferedReader(isr);
//                    String response = br.readLine();
//                    Log.d(TAG, "Received from server string: " + response);

            } catch (UnknownHostException e) {
                Log.e(TAG, "Don't know about host: " + HOST + ":" +PORT);
                Log.e(TAG, e.getMessage());
            } catch (IOException e) {
                Log.e(TAG, "Couldn't get I/O for the connection to: " + HOST + ":" +PORT);
                Log.e(TAG, e.getMessage());
            }
        }
        return null;
    }

    @Override
    protected void onPostExecute(Void res) {
        super.onPostExecute(res);
    }
}

我在活动onStart()中以new OpenSocketTask().execute();打开套接字，并在按钮点击时发送消息，代码为new ServerSendMessageTask(message).execute();。因此，线程不会“重叠”。

另一件事可能是：

我正在尝试将Ping程序包（请参阅第6页here）发送到服务器。只是看它的工作。它看起来像#P#\r\n。如果一切正常，我应该收到这个字符串：#AP#\r\n。

我对Java中的格式并不十分清楚，因此我尝试发送不同的邮件组合：#P#\r\n，#P#\\r\\n，#P#。没有差异。

你能否指出我的错误？

Android |无法使用Socket向/从Wialon服务器发送/接收消息

0 个答案: