UDP安卓客戶端發送（含代碼demo，16進制發送）

udp基礎知識

在前面的，這裏不贅述，這裏再對UDP安卓客戶端和服務器端做一下說明，UDP本身是不區分服務器端和客戶端的，只不過爲了方便理解纔將它這樣區分，其實更好的應該直接說成發送端（客戶端）和接收端（服務器端），兩臺設備在進行通信時，如果通信是雙向的，那麼每個設備都同時是發送端和接收端。
當一端作爲發送端時，它需要明確知道接收端的IP地址和port號，也就是說在做udp客戶端時要說明將要發送信息的目的地址的IP地址和端口號。下面直接來說明整個工程是如何一步一步完成的吧。

AndroidStudio完成整個demo

新建一個工程

打開androidstudio創建一個新的工程

頁面佈局代碼

<?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="發送區"/>

    <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="發送"/>

        <Button
            android:id="@+id/cleantext"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:text="清空發送區" />

        <Button
            android:id="@+id/hex"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:text="16進制格式"/>
    </LinearLayout>

</LinearLayout>

主活動代碼

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相關配置和所使用類對象創建*/
    private int port = 0; //服務器接收端口
    private InetSocketAddress inetSocketAddress = null;
    private DatagramPacket dpReceive = null;
    private DatagramSocket dsReceive = null;
    private byte[] msgReceive = new byte[1024]; //接收緩衝區大小
    private boolean hexString = false;
    private boolean udpServer = false;

    /*UI界面相關控件對象創建*/
    private EditText editport;
    private Button openserver,closeserver,hex,strshow,cleanrec;
    private EditText receive;

    /*其他使用類的創建*/
    private ButtonClick buttonClick = new ButtonClick(); //按鍵事件處理
    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); //開始時佈局文件id=port，程序報錯。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("服務器", "開啓服務器：");
                                }catch (SocketException e){
                                    e.printStackTrace();
                                }

                                dpReceive = new DatagramPacket(msgReceive,msgReceive.length);
                                try {
                                    dsReceive.receive(dpReceive);
                                    Log.i("服務器", "接收到數據包長："+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", "接收到信息並顯示（字符形式）");
                        break;
                }
            }
        }
    }

    /**
     * 字節數組轉換爲十六進制字符串
     *
     * @param b
     *            byte[] 需要轉換的字節數組
     * @return String 十六進制字符串
     */
    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();
    }
}

權限聲明

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

運行效果

PC端接收：

安卓端發送：

相關鏈接

本文工程demo下載，提取碼：8lpd
安卓接收端demo