udp基础知识
在前面的，这里不赘述，这里再对UDP安卓客户端和服务器端做一下说明，UDP本身是不区分服务器端和客户端的，只不过为了方便理解才将它这样区分，其实更好的应该直接说成发送端（客户端）和接收端（服务器端），两台设备在进行通信时，如果通信是双向的，那么每个设备都同时是发送端和接收端。
当一端作为发送端时，它需要明确知道接收端的IP地址和port号，也就是说在做udp客户端时要说明将要发送信息的目的地址的IP地址和端口号。下面直接来说明整个工程是如何一步一步完成的吧。
AndroidStudio完成整个demo
新建一个工程
打开androidstudio创建一个新的工程
页面布局代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1">
<EditText
android:id="@+id/ip"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="3"
android:hint="ip"/>
<EditText
android:id="@+id/port"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="2"
android:hint="port"/>
</LinearLayout>
<EditText
android:id="@+id/sendtext"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="8"
android:gravity="left"
android:text="发送区"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:orientation="horizontal">
<Button
android:id="@+id/send"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:text="发送"/>
<Button
android:id="@+id/cleantext"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:text="清空发送区" />
<Button
android:id="@+id/hex"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:text="16进制格式"/>
</LinearLayout>
</LinearLayout>
主活动代码
package com.example.hh.udpserverdemo;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import java.io.IOException;
import java.lang.ref.WeakReference;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.net.SocketException;
public class MainActivity extends AppCompatActivity {
/*UDP相关配置和所使用类对象创建*/
private int port = 0; //服务器接收端口
private InetSocketAddress inetSocketAddress = null;
private DatagramPacket dpReceive = null;
private DatagramSocket dsReceive = null;
private byte[] msgReceive = new byte[1024]; //接收缓冲区大小
private boolean hexString = false;
private boolean udpServer = false;
/*UI界面相关控件对象创建*/
private EditText editport;
private Button openserver,closeserver,hex,strshow,cleanrec;
private EditText receive;
/*其他使用类的创建*/
private ButtonClick buttonClick = new ButtonClick(); //按键事件处理
private MyHandle myHandle = new MyHandle(this);
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editport = (EditText)findViewById(R.id.portserver); //开始时布局文件id=port，程序报错。更改
openserver = (Button)findViewById(R.id.openServer);
closeserver = (Button)findViewById(R.id.closeServer);
hex = (Button)findViewById(R.id.tohex);
strshow = (Button)findViewById(R.id.tostr);
cleanrec = (Button)findViewById(R.id.cleantxt);
receive = (EditText)findViewById(R.id.receive);
openserver.setOnClickListener(buttonClick);
closeserver.setOnClickListener(buttonClick);
cleanrec.setOnClickListener(buttonClick);
hex.setOnClickListener(buttonClick);
}
private class ButtonClick implements Button.OnClickListener{
@Override
public void onClick(View view) {
switch (view.getId()){
case R.id.openServer:
udpServer = true;
port = Integer.parseInt(editport.getText().toString());
Thread thread = new Thread(new Runnable() {
@Override
public void run() {
inetSocketAddress = new InetSocketAddress(port);
while (udpServer){
try {
dsReceive = new DatagramSocket(inetSocketAddress);
Log.i("服务器", "开启服务器：");
}catch (SocketException e){
e.printStackTrace();
}
dpReceive = new DatagramPacket(msgReceive,msgReceive.length);
try {
dsReceive.receive(dpReceive);
Log.i("服务器", "接收到数据包长："+dpReceive.getLength());
if (hexString){
String rec = byte2hex(dpReceive.getData(),dpReceive.getLength());
Message message = new Message();
message.what = 1;
message.obj = rec;
myHandle.sendMessage(message);
}else {
String rec = new String(dpReceive.getData(),dpReceive.getOffset(),
dpReceive.getLength());
Message message = new Message();
message.what = 1;
message.obj = rec;
myHandle.sendMessage(message);
}
} catch (IOException e) {
e.printStackTrace();
}
}
dsReceive.close();
}
});
thread.start();
break;
case R.id.closeServer:
udpServer = false;
break;
case R.id.cleantxt:
receive.setText("");
break;
case R.id.tohex:
hexString = true;
break;
case R.id.tostr:
hexString = false;
break;
}
}
}
private class MyHandle extends Handler{
private final WeakReference<MainActivity> mActivity;
public MyHandle(MainActivity activity){
mActivity = new WeakReference<MainActivity>(activity);
}
@Override
public void handleMessage(Message msg) {
MainActivity activity = mActivity.get();
if (activity != null){
switch (msg.what){
case 1:
String str = msg.obj.toString();
receive.append(str);
Log.i("UI", "接收到信息并显示（字符形式）");
break;
}
}
}
}
/**
* 字节数组转换为十六进制字符串
*
* @param b
* byte[] 需要转换的字节数组
* @return String 十六进制字符串
*/
public static String byte2hex(byte b[],int length) {
if (b == null) {
throw new IllegalArgumentException(
"Argument b ( byte array ) is null! ");
}
String hs = "";
String stmp = "";
for (int n = 0; n < length; n++) {
stmp = Integer.toHexString(b[n] & 0xff);
if (stmp.length() == 1) {
hs = hs + "0" + stmp;
} else {
hs = hs + stmp;
}
}
return hs.toUpperCase();
}
}
权限声明
<uses-permission android:name="android.permission.INTERNET"/>
运行效果
PC端接收：
安卓端发送：
相关链接
本文工程demo下载，提取码：8lpd
安卓接收端demo