2017/02/06

[Android] UDP Socket Send&Receive with Thread

Android要寫UDP傳輸有點麻煩，因為它對於有關網路的行為有特別的規範，不能直接在MainActivity做任何網路行為，所以必須要另外建立方法來做。
有兩種方法可以寫，一種是透過Thread，另一種是透過AsyncTask(比較推薦)，在這邊先用Thread的方法，建立一個可以傳送跟接收UDP Socket的Android App。


首先Android要寫網路有關的功能的話，App要先開權限！(開發的時候常常會忘記)
在AndroidManifest.xml裡面加入這兩行:

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

接著分別加入兩個class，分別來負責做傳送跟接收的工作
chatsender.java
  1. package com.example.chris.udp_sample;
  2. import java.io.IOException;
  3. import java.net.DatagramPacket;
  4. import java.net.DatagramSocket;
  5. import java.net.InetAddress;
  6. import java.net.SocketException;
  7. import java.net.UnknownHostException;
  8. import android.util.Log;
  9.  
  10. class ChatSender extends Thread{
  11.  
  12.     public void run(String strIP, String str, int port){
  13.         DatagramSocket socket = null;
  14.         try
  15.         {
  16.             socket = new DatagramSocket();
  17.             InetAddress serverAddress = InetAddress.getByName(strIP);
  18.             Log.d("IP Address", serverAddress.toString());
  19.  
  20.             DatagramPacket packet;
  21.  
  22.             //send socket
  23.             packet=new DatagramPacket(str.getBytes(),str.length(),serverAddress,port);
  24.             socket.send(packet);
  25.  
  26.         }
  27.         catch(SocketException e)
  28.         {
  29.             e.printStackTrace();
  30.             String error = e.toString();
  31.             Log.e("Error by Sender", error);
  32.         }
  33.         catch(UnknownHostException e)
  34.         {
  35.             e.printStackTrace();
  36.             String error = e.toString();
  37.             Log.e("Error by Sender", error);
  38.         }
  39.         catch(IOException e)
  40.         {
  41.             e.printStackTrace();
  42.             String error = e.toString();
  43.             Log.e("Error by Sender", error);
  44.         }
  45.         catch(Exception e)
  46.         {
  47.             e.printStackTrace();
  48.             String error = e.toString();
  49.             Log.e("Error by Sender", error);
  50.         }
  51.         finally{
  52.             if(socket != null){
  53.                 socket.close();
  54.             }
  55.         }
  56.     }
  57. }
chatserver.java
  1. package com.example.chris.udp_sample;
  2. import java.io.IOException;
  3. import java.net.DatagramPacket;
  4. import java.net.DatagramSocket;
  5. import android.os.Bundle;
  6. import android.os.Message;
  7. import android.util.Log;
  8.  
  9. class ChatServer extends Thread{
  10.  
  11.     private DatagramSocket server = null;
  12.     private static final int PORT = 8008;
  13.  
  14.     public ChatServer() throws IOException {
  15.         server = new DatagramSocket(PORT);
  16.         Log.d("User","new server socket");
  17.     }
  18.     public void run(){
  19.  
  20.         byte[] byte1024 = new byte[1024];
  21.         //Message msg = new Message();
  22.         //Bundle data = new Bundle();
  23.         DatagramPacket dPacket = new DatagramPacket(byte1024, 100);
  24.         String txt;
  25.         try{
  26.             Log.d("User","runing run()");
  27.             while(true){
  28.                 server.receive(dPacket);
  29.                 while(true)
  30.                 {
  31.                     txt = new String(byte1024, 0, dPacket.getLength());
  32.                     MainActivity.exHandler.sendMessage(MainActivity.exHandler.obtainMessage(1,txt));
  33.                     Log.d("User","Handler send Message");
  34.                     if(true) break;
  35.                 }
  36.                 //CloseSocket(client);
  37.             }
  38.         }
  39.         catch(IOException e)
  40.         {}
  41.     }
  42.  
  43.     private void CloseSocket(DatagramSocket socket) throws IOException{
  44.         socket.close();
  45.     }
  46. }

準備好這兩個class之後就可以在MainActivity裡面call來用了，如果要建立server，為了方便檢查自己的IP位址，在一開始有先加入顯示本身IP位址的程式碼。
在這個App中可以自己輸入要傳送的IP位址以及Socket字串內容。以下是MainActivity程式碼:

MainActivity.java
  1. package com.example.chris.udp_sample;
  2.  
  3. import java.io.IOException;
  4. import java.net.DatagramPacket;
  5. import java.net.DatagramSocket;
  6. import java.net.InetAddress;
  7. import java.net.NetworkInterface;
  8. import java.net.SocketException;
  9. import java.net.UnknownHostException;
  10. import java.util.Enumeration;
  11. import java.util.concurrent.atomic.AtomicBoolean;
  12.  
  13. import android.net.wifi.WifiInfo;
  14. import android.os.StrictMode;
  15. import android.support.v7.app.AppCompatActivity;
  16. import android.os.Bundle;
  17. import android.os.Handler;
  18. import android.os.Message;
  19. import android.text.format.Time;
  20. import android.util.Log;
  21. import android.view.View;
  22. import android.widget.Button;
  23. import android.widget.EditText;
  24. import android.widget.TextView;
  25.  
  26. public class MainActivity extends AppCompatActivity {
  27.  
  28.     public static Handler exHandler;
  29.     private ChatServer chatserver;
  30.     private ChatSender chatsender;
  31.     private TextView texv_ip, texv_recv, texv_send;
  32.     private EditText edt_ip, edt_socket;
  33.     private Button button01;
  34.  
  35.     @Override
  36.     protected void onCreate(Bundle savedInstanceState) {
  37.         super.onCreate(savedInstanceState);
  38.         setContentView(R.layout.activity_main);
  39.  
  40.         if (android.os.Build.VERSION.SDK_INT > 9) {
  41.             StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
  42.             StrictMode.setThreadPolicy(policy);
  43.         }
  44.  
  45.         texv_ip = (TextView) findViewById(R.id.textView);
  46.         texv_recv = (TextView) findViewById(R.id.textView2);
  47.         texv_send = (TextView) findViewById(R.id.textView5);
  48.  
  49.         edt_ip = (EditText)findViewById(R.id.editText);
  50.         edt_socket = (EditText)findViewById(R.id.editText2);
  51.  
  52.         button01 = (Button)findViewById(R.id.btn_send1);
  53.  
  54.         //receive text
  55.         exHandler=new Handler() {
  56.             @Override
  57.             public void handleMessage(Message msg) {
  58.                 super.handleMessage(msg);
  59.                 String msgString = (String)msg.obj;
  60.                 Log.d("Handler","Now in Handler");
  61.                 texv_recv.setText(null);
  62.                 texv_recv.setText("Receive: " + msgString);
  63.             }
  64.         };
  65.  
  66.         //get wifi IP
  67.         StringBuilder IFCONFIG=new StringBuilder();
  68.         try {
  69.             for (Enumeration en = NetworkInterface.getNetworkInterfaces(); en.hasMoreElements();) {
  70.                 NetworkInterface intf = en.nextElement();
  71.                 for (Enumeration enumIpAddr = intf.getInetAddresses(); enumIpAddr.hasMoreElements();) {
  72.                     InetAddress inetAddress = enumIpAddr.nextElement();
  73.                     if (!inetAddress.isLoopbackAddress() && !inetAddress.isLinkLocalAddress() && inetAddress.isSiteLocalAddress()) {
  74.                         IFCONFIG.append(inetAddress.getHostAddress().toString()+"\n");
  75.                     }
  76.                 }
  77.             }
  78.             texv_ip.setText("My IP address is: " + IFCONFIG.toString());
  79.             Log.d("LOG_Text", IFCONFIG.toString());
  80.         } catch (SocketException ex) {
  81.             Log.e("LOG_TAG", ex.toString());
  82.         }
  84.         try{
  85.             chatsender = new ChatSender();
  86.             chatserver = new ChatServer();
  87.             chatserver.start();
  88.             Log.d("User","Thread start...");
  90.         }catch(Exception e)
  91.         {
  92.             String str = e.toString();
  93.             Log.e("Error by User", str);
  94.         }
  96.     }
  98.     protected void onStart(){
  99.         super.onStart();
  101.         button01.setOnClickListener(new Button.OnClickListener(){
  102.             @Override
  103.             public void onClick(View v) {
  104.                 chatsender.run(edt_ip.getText().toString(), edt_socket.getText().toString(), 8008);
  105.                 texv_send.setText("Send " + edt_socket.getText().toString() + " to " + edt_ip.getText().toString());
  106.             }
  107.         });
  109.     }
  111.     protected void onPause(){
  112.         super.onPause();
  113.         if(chatserver != null)
  114.         {
  115.             if(!chatserver.isInterrupted())
  116.             {
  117.                 chatserver.interrupt();
  118.             }
  119.         }
  121.         if(chatsender != null)
  122.         {
  123.             if(!chatsender.isInterrupted())
  124.             {
  125.                 chatsender.interrupt();
  126.             }
  127.         }
  128.     }
  130.     protected void onResume() {
  131.         super.onResume();
  132.     }
  133. }

以下是layout的部分:
activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.chris.udp_sample.MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="0.33"
        android:text="My IP address"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="20dp" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="0.33"
        android:text="Receive: null"
        android:layout_below="@+id/textView"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="20dp"/>

    <TextView
        android:id="@+id/textView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="0.33"
        android:text="Send IP: "
        android:layout_below="@+id/textView2"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="20dp" />

    <TextView
        android:id="@+id/textView4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="0.33"
        android:text="Send Socket: "
        android:layout_below="@+id/textView3"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="20dp"/>

    <EditText
        android:id="@+id/editText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPersonName"
        android:text="172.20.10.2"
        android:ems="10"
        android:layout_alignBaseline="@+id/textView3"
        android:layout_alignBottom="@+id/textView3"
        android:layout_toRightOf="@+id/textView3"
        android:layout_toEndOf="@+id/textView3" />

    <EditText
        android:id="@+id/editText2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPersonName"
        android:text="test"
        android:ems="10"
        android:layout_alignBaseline="@+id/textView4"
        android:layout_alignBottom="@+id/textView4"
        android:layout_toRightOf="@+id/textView4"
        android:layout_toEndOf="@+id/textView4" />

    <Button
        android:id="@+id/btn_send1"
        android:text="Send"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/textView4"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="20dp" />

    <TextView
        android:id="@+id/textView5"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="0.33"
        android:text="show send socket"
        android:layout_below="@+id/btn_send1"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="20dp"/>

</RelativeLayout>

這是用Thread的方法寫的，之後會再補一篇用AsyncTask的方法來做UDP傳輸的功能。




張貼者： 於
標籤： ,

2 則留言:

  1. 匿名2018年1月12日 下午1:12

    ChatServer.java中并没有start() function
    try{
    chatsender = new ChatSender();
    chatserver = new ChatServer();
    chatserver.start(); //------>>>>>>>>>>ChatServer.java中并没有start() function
    Log.d("User","Thread start...");
    }catch(Exception e)
    {
    String str = e.toString();
    Log.e("Error by User", str);
    }

    回覆刪除
    回覆
    1. 匿名2018年4月23日 上午11:56

      因為ChatServer是繼承Thread來用，start()是Thread裡面的function

      刪除

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