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2015年12月4日 星期五

Android 與Arduino 資料交換方式

當你想要從手機發送訊息給Arduino或想從Arduino收到回傳訊息時都必須知道如何使用DataInputStream /  DataOutStream

Example01  Example02

android的網路資料交換分為2種:基於socket的,和基於http協定的。

自己玩Android 與Arduino不論是透過藍芽 HC-05、HC-06或是無線網路ESP8266 都是用Socket方式來做資料交換。網路上這篇文章說明很清楚值得大家參考

基於socket的用法


  伺服器端:-----------------------------------------------------------------------------------------

  先啟動一個伺服器端的socket ServerSocket svr = new ServerSocket(8989);

  開始偵聽請求         
        Socket s = svr.accept();

  取得輸入和輸出
  DataInputStream dis = new DataInputStream(s.getInputStream());

  DataOutputStream dos = new DataOutputStream(s.getOutputStream());

  Socket 的交互通過流來完成,即是說傳送的位元組流,因此任何檔都可以在上面傳送。

        誰打開的記得要關上。

  用DataInputStream/DataOutputStream來進行包裝是因為我們想要他們對基底資料型別的讀寫功能readInt(),writeInt(),readUTF(),writeUTF()等等。

  用戶端:-----------------------------------------------------------------------------------------

  發起一個socket連接      
        Socket s = new Socket("192.168.1.16",8015);

  取得輸入和輸出
     DataInputStream dis = new DataInputStream(s.getInputStream());
  DataOutputStream dos = new DataOutputStream(s.getOutputStream());

  之後就可以相互通信了。誰打開的記得要關上。


 InputStream is = new FileInputStream("test");
    //暫存BYTE陣列
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    //緩衝
    byte buffer[] = new byte[512];
    //紀錄讀進來長度
    int length = 0;
    //假如等於-1代表沒有資料了
    while( (length = is.read(buffer)) != -1){
            //從緩衝區讀取buffer裡面0~length-1的位置
            baos.write(buffer, 0, length);
    }
    //ByteArrayOutputStream轉成位元陣列
    byte data [] = baos.toByteArray();
    is.close();
    baos.close();





基於Http協定


  一般是發送請求到某個應用伺服器。此時需要用到HttpURLConnection

  先取得HttpURLConnection urlConn = new URL("http://www.google.com").openConnection();

  設置標誌 

    urlConn.setDoOutput(true); urlConn.setDoInput(true);//post的情況下需要設置DoOutput為true

    urlConn.setRequestMethod("POST");

    urlConn.setUseCache(false);//設置是否用緩存

    urlConn.setRequestProperty("Content-type","application/x-www-form-urlencoded");//設置content-type

  獲得輸出流,便於想伺服器發送資訊。

    DataOutputStream dos = new DataOutputStream(urlConn.getOutputStream());

  望流裡面寫請求參數

    dos.writeBytes("name="+URLEncoder.encode("chenmouren","gb2312");

    dos.flush();dos.close();//發送完後馬上關閉。

  獲得輸入流,取資料

    BufferReader reader = new BufferedReader(new InputStreamReader(urlConn.getInputStream()));

    reader.readLine();//用 !=null來判斷是否結束

    reader.close();

  讀完了記得關閉connection  urlConn.disconnect();


//-----------------------------------------------

import java.io.*;
import java.net.*;

public class client
{
 public static void main(String [] argv)throws IOException
 {
  StartClient(1234);
 }
 public static void StartClient(int port)
 {
  try
  {
   //設定連線的主機位置
   InetAddress add = InetAddress.getByName("ecc.johnsonlu.org");
   SocketAddress sc_add= new InetSocketAddress(add,port);
   Socket sc = new Socket();
   int timeout = 2000 ; //timeout 2秒
   System.out.println("連線中....");
   //與主機連線
   sc.connect(sc_add,timeout);
   System.out.println(sc.getLocalAddress() + "連線到" + sc.getInetAddress());
   
   //傳送資料到Server端
   DataOutputStream out = new DataOutputStream(sc.getOutputStream());
   out.writeUTF("我是Client");
   out.flush();
   
   //接收Server端資料
   DataInputStream in = new DataInputStream(sc.getInputStream());
   System.out.println("Server:" + in.readUTF());
   
   
  }
  catch(SocketTimeoutException e)
  {
   System.out.println("Timeout");
  }
  catch(IOException e)
  {
   e.printStackTrace();
  }
 }
}






//----------------------------------------------
Client:
try{

Socket socket = new Socket(mDestinationIP,mDestinationPort);

DataInputStream dataInputStream = new

            DataInputStream(socket.getInputStream());

int data;
//read data from server

while ((data=dataInputStream.read()) != -1) {
            //do sth
}

} catch (IOException e){
            //handle socket IOExceptions
}

Client Buffered data streaming
try{

Socket socket = new Socket(mDestinationIP,mDestinationPort);
BufferedInputStream bufferedInputStream = new
 BufferedInputStream((socket.getInputStream());
int data;
//read date from server

while ((data= bufferedInputStream.read()) != -1) {
            //do sth
}

} catch (IOException e){
            //handle socket IOExceptions
}

//---------------------------------------


import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;
import java.net.UnknownHostException;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class AndroidClient extends Activity {

EditText textOut;
TextView textIn;

 /** Called when the activity is first created. */
 @Override
 public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.main);
  
     textOut = (EditText)findViewById(R.id.textout);
     Button buttonSend = (Button)findViewById(R.id.send);
     textIn = (TextView)findViewById(R.id.textin);
     buttonSend.setOnClickListener(buttonSendOnClickListener);
 }

 Button.OnClickListener buttonSendOnClickListener
 = new Button.OnClickListener(){

@Override
public void onClick(View arg0) {
 // TODO Auto-generated method stub
 Socket socket = null;
 DataOutputStream dataOutputStream = null;
 DataInputStream dataInputStream = null;

 try {
  socket = new Socket("192.168.1.101", 8888);
  dataOutputStream = new DataOutputStream(socket.getOutputStream());
  dataInputStream = new DataInputStream(socket.getInputStream());
  dataOutputStream.writeUTF(textOut.getText().toString());
  textIn.setText(dataInputStream.readUTF());
 } catch (UnknownHostException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
 } catch (IOException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
 }
 finally{
  if (socket != null){
   try {
    socket.close();
   } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
  }

  if (dataOutputStream != null){
   try {
    dataOutputStream.close();
   } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
  }

  if (dataInputStream != null){
   try {
    dataInputStream.close();
   } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
  }
 }
}};
}



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