无法打印从套接字连接中获取的值

Question

public class MyClientTask extends AsyncTask<String, String, String> {

    String dstAddress;
    int dstPort;

    MyClientTask(String addr, int port) {
        dstAddress = addr;
        dstPort = port;
    }

    protected String doInBackground(String... arg0) {
        String response = "";
        Socket socket = null;

        try {
            socket = new Socket(dstAddress, dstPort);
            BufferedReader stdIn = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            while ((response = stdIn.readLine()) != null) {
                Log.i("response", response);
                publishProgress(response);
            }
            Log.i("response", response);

        } catch (UnknownHostException e) {
            e.printStackTrace();
            response = "UnknownHostException: " + e.toString();
        } catch (IOException e) {
            e.printStackTrace();
            response = "IOException: " + e.toString();
        } catch (Exception e) {
            e.printStackTrace();
        }

        return response;
    }

    protected void onProgressUpdate(String... values) {

        Log.i("prama", values[0]);
        super.onProgressUpdate(values);

    }
    @Override
    protected void onPostExecute(String result) {
        Toast.makeText(MainActivity.this, result, Toast.LENGTH_LONG).show();
        super.onPostExecute(result);
    }

}

我编写上面的代码来从socket读取值。当我启动异步任务时，值将在日志中打印，就像在doInbackground中一样，但是在异步任务完成后我的toast消息不会被触发。