//wird in der onCreate methdode ausgeführt
 //wenn ich im WLAN netz drinnen bin, dann beginne ich Daten zu empfangen
  if(mobile.isConnected() == true) {
            //Log.d("network", "IST IM WLAN");
         sendData(REFRESH);
         startSniffing();
  }
 
//starten des Threads;
 private void startSniffing(){
  if(!tt.isAlive()){
   try {
    receiveSocket = new DatagramSocket(empf_port);
       tt.start();
   }
   catch (SocketException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
  } 
 }
//stopen des Threads:
private void stopSniffing(){
  if(tt.isAlive()){
   tt.stop();
   receiveSocket.close();
  }
 }
//senden der Daten
[LEFT]public void sendData(String data){
try{
DatagramSocket clientSocket = new DatagramSocket();
InetAddress IPAddress;


byte[] sendData = new byte[1024]; 
sendData=data.getBytes();
IPAddress = InetAddress.getByName("192.168.0.255");
DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, server_port);
clientSocket.send(sendPacket);
Log.d("udp tutorial", "senden erfolgreich");

clientSocket.close();
}
catch (SocketException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}[/LEFT]
}
//Erhalten der Daten:
 public void run() {
  // TODO Auto-generated method stub
  while(true) {
   try {
    byte[] buffer = new byte[1024];
    DatagramPacket p = new DatagramPacket(buffer, buffer.length);
    receiveSocket.receive(p);
    byte[] packet = new byte[p.getLength()];
    System.arraycopy(p.getData(), 0, packet, 0, packet.length);
    text = new String(packet, "UTF8");
    Log.d("Udp tutorial","message:" + text);
    Log.d("RECEIVE", "ERFOLGREICH");   
    handler.sendEmptyMessage(0);
   } 
    catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
   catch (Exception e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
  }
 }
 
//wenn ich zurück switche rufe ich einfach die stopSniffing und stoppe den Thread
public void onClick(View v) {[/LEFT]
if(v.equals(zuruck)){[/LEFT]
stopSniffing();[/LEFT]
Intent in = new Intent(Heizung.this,AndroidSteuerung.class);[/LEFT]
startActivity(in);[/LEFT]
}

while(true){...}