android的UDP编程实例

WifiManager manager = (WifiManager) this
                .getSystemService(Context.WIFI_SERVICE);
WifiManager.MulticastLock lock= manager.createMulticastLock("test wifi");

<uses-permission android:name="android.permission.CHANGE_WIFI_MULTICAST_STATE" />

public void onCreate() {//用于创建线程
        WifiManager manager = (WifiManager) this
                .getSystemService(Context.WIFI_SERVICE);
        udphelper = new UdpHelper(manager);

        //传递WifiManager对象，以便在UDPHelper类里面使用MulticastLock
        udphelper.addObserver(MsgReceiveService.this);
        tReceived = new Thread(udphelper);
        tReceived.start();
        super.onCreate();
    }

package com.example.com.ihome.bang.util;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.MulticastSocket;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.util.Observable;
import com.example.com.ihome.bang.tool.SendThread;
import android.net.wifi.WifiManager;
import android.util.Log;
/**
 *
 * UdpHelper帮助类
 *
 * @author 陈喆榕
 *
 */
public class UdpHelper  implements Runnable {
    public    Boolean IsThreadDisable = false;//指示监听线程是否终止
    private static WifiManager.MulticastLock lock;
    InetAddress mInetAddress;
    public UdpHelper(WifiManager manager) {
         this.lock= manager.createMulticastLock("UDPwifi");
    }
    public void StartListen()  {
        // UDP服务器监听的端口
        Integer port = 8903;
        // 接收的字节大小，客户端发送的数据不能超过这个大小
        byte[] message = new byte[100];
        try {
            // 建立Socket连接
            DatagramSocket datagramSocket = new DatagramSocket(port);
            datagramSocket.setBroadcast(true);
            DatagramPacket datagramPacket = new DatagramPacket(message,
                    message.length);
            try {
                while (!IsThreadDisable) {
                    // 准备接收数据
                    Log.d("UDP Demo", "准备接受");
                     this.lock.acquire();

                    datagramSocket.receive(datagramPacket);
                    String strMsg=new String(datagramPacket.getData()).trim();
                    Log.d("UDP Demo", datagramPacket.getAddress()
                            .getHostAddress().toString()
                            + ":" +strMsg );this.lock.release();
                }
            } catch (IOException e) {//IOException
                e.printStackTrace();
            }
        } catch (SocketException e) {
            e.printStackTrace();
        }
    }
    public static void send(String message) {
        message = (message == null ? "Hello IdeasAndroid!" : message);
        int server_port = 8904;
        Log.d("UDP Demo", "UDP发送数据:"+message);
        DatagramSocket s = null;
        try {
            s = new DatagramSocket();
        } catch (SocketException e) {
            e.printStackTrace();
        }
        InetAddress local = null;
        try {
            local = InetAddress.getByName("255.255.255.255");
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
        int msg_length = message.length();
        byte[] messageByte = message.getBytes();
        DatagramPacket p = new DatagramPacket(messageByte, msg_length, local,
                server_port);
        try {
            s.send(p);
            s.close();

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    @Override
    public void run() {
            StartListen();
    }
}