android中udp接收数据,如何在Android中使用UDP接收数据？

我使用以下代码从特定端口接收数据.它不适用于Android.但是将数据发送到特定端口工作正常.

public class UDPDemo extends Activity {

private TextView tv;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

tv = (TextView)findViewById(R.id.recv_message);

try {

DatagramSocket clientsocket=new DatagramSocket(9876);

byte[] receivedata = new byte[1024];

while(true)

{

DatagramPacket recv_packet = new DatagramPacket(receivedata, receivedata.length);

Log.d("UDP", "S: Receiving...");

clientsocket.receive(recv_packet);

String rec_str = new String(recv_packet.getData());

tv.setText(rec_str);

Log.d(" Received String ",rec_str);

InetAddress ipaddress = recv_packet.getAddress();

int port = recv_packet.getPort();

Log.d("IPAddress : ",ipaddress.toString());

Log.d(" Port : ",Integer.toString(port));

}

} catch (Exception e) {

Log.e("UDP", "S: Error", e);

}

}

}