搜索吧：关键词：android， udp， 局域网， lan，广播，源代码
最近公司在做一个游戏项目，互联网对战方面的东东已经差不多搞定，还剩下局域网方面的东东没做，大概的功能需求是需要达到像飞鸽差不多的效果吧，但是在网络查了一天关于android的局域网广播的资料，不管是国内的还是国外的，发现没多少，大部分都是问，但是具体怎么解决的有答案的很少，自己摸索了一下，今天上午做了一个demo，能够看到局域网的通信效果了。有了个demo看到效果了就感觉有了很大的希望了。
关于广播组的ip问题，可以参看这篇帖子http://www.gznc.edu.cn/yxsz/jjglxy/book/Java_api/java/net/MulticastSocket.html，不是什么自己ip地址后面改为255，也不是改成网关之类的。
下面把demo的客户端和服务器端代码贴出来：
package com.test;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.util.Enumeration;
import android.content.Context;
import android.net.wifi.WifiManager;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.widget.Toast;
public class MulticastServer implements Runnable{
private InetAddress mBroadcastAddr;
private DatagramSocket mSocket;
private DatagramPacket mDatagram;
// private String mSendData = "AAAA";
private byte[] mBuffer = null;
// mSendData.getBytes();
public static final int SERVER_SEND_PORT = 4445;
public static final int CLIENT_RECEIVE_PORT = 4446;
//Seehttp://www.gznc.edu.cn/yxsz/jjglxy/book/Java_api/java/net/MulticastSocket.html
public static final String BROADCAST_IP = "234.5.6.7";
private Thread mThread = null;
private static final String TAG = "MulticastServer";
private Context mContext = null;
public MulticastServer(Context context){
Log.d(TAG, "######## MulticastServer ##########");
mContext = context;
WifiManager wifiManager = (WifiManager)context.getSystemService(Context.WIFI_SERVICE);
WifiManager.MulticastLock multicastLock = wifiManager.createMulticastLock("mydebuginfo");
multicastLock.acquire();
try {
mSocket = new DatagramSocket(SERVER_SEND_PORT);
} catch (SocketException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
mBroadcastAddr=InetAddress.getByName(BROADCAST_IP);
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Log.d(TAG, "MulticastServer");
mBuffer = getLocalIpAddress().getBytes();
String str = new String(mBuffer);
Log.d(TAG, "mBuffer = " + str);
mDatagram = new DatagramPacket(mBuffer, mBuffer.length, mBroadcastAddr, CLIENT_RECEIVE_PORT);
mThread = new Thread(this);
}
public void startSend() {
Log.d(TAG, "startSend");
SEND_FLAG = true;
mThread.start();
}
public void stopSend() {
SEND_FLAG = false;
}
private boolean SEND_FLAG = true;
@Override
public void run() {
// TODO Auto-generated method stub
while(SEND_FLAG) {
broadcast_data();
}
}
private String sendStr = "";
private void broadcast_data()
{
try {
Log.d(TAG, "broadcast_data");
mSocket.send(mDatagram);
sendStr = new String(mDatagram.getData());
Log.d(TAG, "send ok data = " + sendStr);
mHandler.sendEmptyMessage(TOAST_MSG_SEND);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
Thread.sleep(200);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public String getLocalIpAddress() {
try {
for (Enumeration<NetworkInterface> en = NetworkInterface
.getNetworkInterfaces(); en.hasMoreElements();) {
NetworkInterface intf = en.nextElement();
for (Enumeration<InetAddress> enumIpAddr = intf
.getInetAddresses(); enumIpAddr.hasMoreElements();) {
InetAddress inetAddress = enumIpAddr.nextElement();
if (!inetAddress.isLoopbackAddress()) {
return inetAddress.getHostAddress().toString();
}
}
}
} catch (SocketException ex) {
Log.e("WifiPreference IpAddress", ex.toString());
}
return "";
}
private final int TOAST_MSG_SEND = 0x01;
private Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch(msg.what) {
case TOAST_MSG_SEND:
Toast.makeText(mContext, sendStr, Toast.LENGTH_SHORT).show();
}
}
};
}
下面是Client端代码：
package com.test;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.InetAddress;
import java.net.MulticastSocket;
import android.content.Context;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.widget.Toast;
public class MulticastClient implements Runnable {
private MulticastSocket mMultiSocket;
private InetAddress mAddress;
private boolean mScan = false;
private Thread mThread = null;
private byte[] mBuffer = new byte[256];
private DatagramPacket mDatagram = null;
private static final String TAG = "MulticastClient";
private Context mContext = null;
public MulticastClient(Context context) throws IOException {
mContext = context;
Log.d(TAG, "######## MulticastClient #########");
mAddress = InetAddress.getByName(MulticastServer.BROADCAST_IP);
mMultiSocket = new MulticastSocket(MulticastServer.CLIENT_RECEIVE_PORT);
mMultiSocket.joinGroup(mAddress);
Log.d(TAG, "MulticastClient");
mThread = new Thread(this);
// scan_recv();
}
public void startReceive() {
this.mScan = true;
mThread.start();
}
public void stopReceive() {
this.mScan = false;
}
@Override
public void run() {
// TODO Auto-generated method stub
Log.d(TAG, "run");
scan_recv();
}
private String receiveStr = "";
public void scan_recv() {
// DatagramPacket packet;
while (mScan) {
Log.d(TAG, "scan_recv");
try {
mDatagram = new DatagramPacket(mBuffer, mBuffer.length);
mMultiSocket.receive(mDatagram);
receiveStr = new String(mDatagram.getData());
Log.v(TAG, "^^^^^^^^^data = " + receiveStr + "^^^^^^^^^^^^");
mHandler.sendEmptyMessage(TOAST_MSG_RECEIVE);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
this.mScan = false;
}
try {
Log.d(TAG, "sleep");
Thread.sleep(100);
// sleep(5000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
private final int TOAST_MSG_RECEIVE = 0x01;
private Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case TOAST_MSG_RECEIVE:
Toast.makeText(mContext, receiveStr, Toast.LENGTH_SHORT).show();
}
}
};
}
不过有个问题，在模拟器上收不到消息，只能收自己的，跟真机通信不了，试了网上别人说的还是没效果，反正有几个平板可以用，就不折腾这个问题了，用知道怎么解决这个问题的童鞋麻烦教我一下啦，谢谢。
截了一张demo图，这是模拟器上自己发送，自己接收的效果。
整个demo的代码我放到我的下载里面，想要的可以自己去取。（别给我留邮箱，留也没时间发）