我同时运行服务器应用程序和客户端应用程序，但客户端无法向服务器发送消息

我是套接字编程的新手，现在我想有一个聊天应用程序，客户端是我的 PC 中的模拟器，服务器现在也是我 PC 上的 c# 应用程序。我用"127.0.0.1"为客户端设置了服务器IP。我同时运行服务器应用程序和客户端应用程序，但客户端无法向服务器发送消息。出了什么问题？这是服务器端：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net.Sockets;
namespace serverConsol
{
    class Program
    {
        static void Main(string[] args)
        {
            TcpListener serverSocket = new TcpListener(8888);
            int requestCount = 0;
            TcpClient clientSocket = default(TcpClient);
            serverSocket.Start();
            Console.WriteLine(" >> Server Started");
            clientSocket = serverSocket.AcceptTcpClient();
            Console.WriteLine(" >> Accept connection from client");
            requestCount = 0;
            while ((true))
            {
                try
                {
                    requestCount = requestCount + 1;
                    NetworkStream networkStream = clientSocket.GetStream();
                    byte[] bytesFrom = new byte[10025];
                    networkStream.Read(bytesFrom, 0, (int)clientSocket.ReceiveBufferSize);
                    string dataFromClient = System.Text.Encoding.ASCII.GetString(bytesFrom);
                    dataFromClient = dataFromClient.Substring(0, dataFromClient.IndexOf("$"));
                    Console.WriteLine(" >> Data from client - " + dataFromClient);
                    string serverResponse = "Last Message from client" + dataFromClient;
                    Byte[] sendBytes = Encoding.ASCII.GetBytes(serverResponse);
                    networkStream.Write(sendBytes, 0, sendBytes.Length);
                    networkStream.Flush();
                    Console.WriteLine(" >> " + serverResponse);
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.ToString());
                }
            }
            clientSocket.Close();
            serverSocket.Stop();
            Console.WriteLine(" >> exit");
            Console.ReadLine();
        }
    }
}

这是Android代码（作为Clinet）：包 com.app.client1;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.Socket;
import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class MainActivity extends Activity 
{
    Thread ClientSocketTread;
    String message="hi Server";
    public   String ServeripFoConnect="127.0.0.1";
    public int Serverport=8888;
    Socket requestSocket;
    public PrintWriter out;
    public TextView LbMsg;
    public EditText InputMsg;
    public Button BtnSend;
    public Runnable MyClientsend = new Runnable()
    {
        public void run()
        {
        try 
            {
             BufferedReader receiveRead;
             InetAddress serverAddr = InetAddress.getByName(ServeripFoConnect);//TCPServer.SERVERIP          
             requestSocket = new Socket(serverAddr, Serverport);
             while (true) 
             {
                 try 
                 {
                     if (message != "")
                     {
                          out = new PrintWriter( new BufferedWriter( new OutputStreamWriter(requestSocket.getOutputStream())),true);
                          out.println(message);
                          out.flush();
                          message="";
                          try 
                          {
                              receiveRead = new BufferedReader(new InputStreamReader(requestSocket.getInputStream()));
                                if(( receiveRead.read()) != -1) //receive from server
                                {
                                    char[] buff = new char[(receiveRead.read()) +1];
                                    receiveRead.read(buff);
                                    int i;
                                    StringBuilder response= new StringBuilder();
                                    for(i=0;i<buff.length ;i++)
                                    {
                                        response.append( buff[i] );
                                    }
                                    String result = response.toString();
                                } //end seccond if  
                        } catch (Exception e) 
                        {
                            // TODO: handle exception
                            Log.d("e111111111",e .toString());
                            try 
                            {
                                Log.d("e2222222222",e.toString());
                            } 
                            catch (Exception e2) 
                            {
                                // TODO: handle exception
                                Log.d("e33333333333",e2 .toString());
                            }
                        }
                     }//end first if
                     Thread.sleep(1000);
                } 
                 catch (Exception e) 
                 {
                    // TODO: handle exception
                    Log.d("e44444444",e .toString());
                    requestSocket.close();
                }
            }//end while
        } //end first try
        catch (Exception e) 
        {
            Log.d("e555555555",e .toString());
        } 
        finally 
        {
        }//end finally
    }//end run
  };//end runnable
    //EbdClient Socket
   //-------------------------------------------------- 
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //initial Object
                LbMsg=(TextView) findViewById(R.id.LbMsg);
                InputMsg=(EditText) findViewById(R.id.TbXInput);
                BtnSend=(Button) findViewById(R.id.BtnSend);    
                    try 
                    {
                        ClientSocketTread = new Thread( MyClientsend);
                        ClientSocketTread.start();
                    } catch (Exception e) 
                    {
                        // TODO: handle exception
                         LbMsg.setText("ClientSocketTread  not Start");
                    }
    }
    //------------------------------------------
    @Override
    public boolean onCreateOptionsMenu(Menu menu) 
    {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    //------------------------------------------
    @Override
    protected void onPause() 
    {
        super.onPause();
        try 
        {
            ClientSocketTread.stop();
        } 
        catch (Exception e) 
        {
        }
    }
    //------------------------------------------
    ///Onclick Function
public void Onclick(View v)
{
    switch (v.getId()) 
        {
           case R.id.BtnSend:
            try 
            {
                message=InputMsg.getText().toString();
            }
            catch (Exception e) 
            {
                LbMsg.setText("Erroe" + e);
            }
            break;
        }
    }
}