AndroidUDP网络传输聊天程序

package com.android; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; import android.app.Activity; import android.os.Bundle; import android.os.Message; import android.text.TextUtils; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; public class ActivityMain extends Activity { //发送的消息内容 EditText msgEditText = null; //显示消息内容 LinedText msgText = null; //数据报Socket DatagramSocket socket = null; //服务器地址 InetAddress address = null; //连接IP端口号 String ip = "192.168.1.101"; int port = 2345; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); final Button sendBtn = (Button)findViewById(R.id.sendBtn); msgEditText =(EditText)findViewById(R.id.msgEditText); //ListView显示消息 msgText =(LinedText)findViewById(R.id.msgText); try{ //实例化一个数据报Socket socket = new DatagramSocket(); //服务器地址 address = InetAddress.getByName(ip); } catch (Exception ex){ ex.printStackTrace(); //输出出错信息 } //发送消息 sendBtn.setOnClickListener(new OnClickListener(){ public void onClick(View v){ try { //取得编辑框中我们输入的内容 String msg = msgEditText.getText().toString().trim(); //编码为GB2312发送 byte[] msg_byte = msg.getBytes("GB2312"); //实例化一个数据报 DatagramPacket packet = new DatagramPacket(msg_byte,msg_byte.length,address,port); //发送报文 socket.send(packet); msgEditText.setText(""); msgText.append("send:" + msg); msgText.append("\n"); //接受回应 //缓冲区数组 byte[] buffer = new byte[256]; DatagramPacket receivePacket = new DatagramPacket(buffer,buffer.length,address,port); socket.receive(receivePacket); //计算buffer中的有效数据长度 int l = 0; for(byte b:buffer){ if(b!=0){ l++; } } String receivedMessage = new String(buffer,0,l); //显示服务器返回信息更新到TextView msgText.append("received:"+receivedMessage); msgText.append("\n"); }catch (Exception e) { e.printStackTrace(); } } }); } /** * 返回退出 */ @Override public void onBackPressed() { // TODO Auto-generated method stub try { //关闭端口 socket.close(); } catch (Exception e) { e.printStackTrace(); } super.onBackPressed(); } }