套接字已关闭 - C# 服务器 Android 客户端

我有以下代码。我的 c# 服务器和 Android 客户端可以在单击连接按钮时无缝连接，但在连接后我无法将数据从 android 客户端发送到 c# 服务器，Android 客户端说："套接字已关闭"

当我单击连接

按钮时，android是连接并且服务器接受，但我单击发送客户端说套接字已关闭

C# 服务器

    public class SoketPaketi
    {
        public Socket soket;
        public int istemciNo;
        public byte[] tampon = new byte[1024];
        public SoketPaketi(Socket soc, int no)
        {
            this.soket = soc;
            this.istemciNo = no;
        }
    }
    public Form1()
    {
        InitializeComponent();
    }
    private void Form1_Load(object sender, EventArgs e)
    {
        dinlemeyeBasla();
    }
    private void dinlemeyeBasla()
    {
        sunucuSoketi = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        IPEndPoint IP_PORT = new IPEndPoint(IP_ADRES,PORT);
        sunucuSoketi.Bind(IP_PORT);
        sunucuSoketi.Listen(10);
        Console.WriteLine("Server Dinlemeye Başladı.. " + IP_PORT.ToString());
        sunucuSoketi.BeginAccept(new AsyncCallback(onBaglanmaIstegiGeldiginde), null);
    }
    private void onBaglanmaIstegiGeldiginde(IAsyncResult ar)
    {
        Socket calismaSoketi = sunucuSoketi.EndAccept(ar);
        istemciler.Add(calismaSoketi);
        veriBekle(calismaSoketi,istemciler.Count - 1);
        sunucuSoketi.BeginAccept(new AsyncCallback(onBaglanmaIstegiGeldiginde), null);
        Console.WriteLine("İstemci Bağlantısı Kabul Edildi..");
    }
    private void veriBekle(Socket socket, int istemciNo)
    {
        try
        {
            if (geriBildirim == null)
            {
                geriBildirim = new AsyncCallback(onVeriGeldiginde);
            }
            SoketPaketi soketPaketi = new SoketPaketi(socket, istemciNo);
            socket.BeginReceive(soketPaketi.tampon, 0, soketPaketi.tampon.Length,SocketFlags.None, onVeriGeldiginde, soketPaketi);
        }
        catch (SocketException se)
        {
            MessageBox.Show(se.Message);
        }
    }
    private void onVeriGeldiginde(IAsyncResult ar)
    {
        //Console.WriteLine("onVeriGeldiginde");
        SoketPaketi soketPaketi = (SoketPaketi)ar.AsyncState;
        int gelenBoyut = soketPaketi.soket.EndReceive(ar);
        if (gelenBoyut > 0)
        {
            char[] karakterler = new char[gelenBoyut + 1];
            Decoder d = Encoding.UTF8.GetDecoder();
            int karakterUzunlugu = d.GetChars(soketPaketi.tampon, 0, gelenBoyut, karakterler, 0);
            String gelenVeri = new String(karakterler);
            Console.WriteLine("İstemciden Veri Geldi.. Gelen Veri : " + gelenVeri);
            Console.WriteLine("Data Recieved from client.. Received Data : " + gelenVeri);
        }
        veriBekle(soketPaketi.soket, soketPaketi.istemciNo);
    }
}

}

安卓客户端

/*********************** Bağlan *********************/
/*********************** Connect *********************/
public class Baglan extends AsyncTask<Void,Void,Void> {
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        progressDialog = new ProgressDialog(context);
        progressDialog.setMessage("Sunucuya Bağlanılıyor..!");
        progressDialog.show();
    }
    @Override
    protected Void doInBackground(Void... args) {
        InetAddress serverAddr = null;
        try {
            serverAddr = InetAddress.getByName(Evrensel.SERVER_IP);
            socket = new Socket(serverAddr, Evrensel.SERVER_PORT);
            Log.d("FEF","Evrensel Socket bağlandı.." + socket.isConnected());
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (socket != null) {
                try {
                    socket.close();
                    socket = null;
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return null;
    }
    @Override
    protected void onPostExecute(Void v) {
        super.onPostExecute(v);
        progressDialog.dismiss();
    }
}
/*********************** Send Message *********************/
/*********************** Mesaj Gönder *********************/
public class MesajGonder extends AsyncTask <String, Void, String> {
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        progressDialog = new ProgressDialog(context);
        progressDialog.setMessage("Sunucuya Mesaj Gönderiliyor..!");
        progressDialog.show();
    }
    @Override
    protected String doInBackground(String... args) {
        String serverResponse = "";
        PrintWriter mBufferOut = null;
        try {
            mBufferOut = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())), true);
            mBufferOut.println(args[0]);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return serverResponse;
    }
    @Override
    protected void onPostExecute(String s) {
        super.onPostExecute(s);
        progressDialog.dismiss();
    }
}

public class MainActivity extends ActionBarActivity {
    public static Socket socket;
    public static final String SERVER_IP = "192.168.1.81";
    public static final int SERVER_PORT = 6000;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button btnBaglan = (Button)findViewById(R.id.btnBaglan);
        btnBaglan.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                new Thread(new Baglan()).start();
            }
        });
        Button btnGonder = (Button)findViewById(R.id.btnGonder);
        btnGonder.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                new Thread(new MesajGonder()).start();
            }
        });
    }
    public class Baglan implements Runnable {
        @Override
        public void run() {
            InetAddress serverAddr = null;
            try {
                serverAddr = InetAddress.getByName(SERVER_IP);
                socket = new Socket(serverAddr, SERVER_PORT);
            } catch (UnknownHostException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
            Log.d("FEF", "Socket bağlandımı:" + socket.isConnected());
        }
    }
    public class MesajGonder implements Runnable{
        @Override
        public void run() {
            PrintWriter mBufferOut = null;
            try {
                mBufferOut = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())), true);
                mBufferOut.println("Breko breko");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}