Android設備之間通過Wifi通信

　　之前寫過PC與Android之間通過WIFI通信（通過Socket，可以在博客里面搜索），PC作為主機，Android作為客戶機，現在手頭有一台儀器通過wifi傳輸數據，如果儀器作為主機發射WIFI熱點信號，Android需要連接到該熱點才能進一步進行通信，但是由於主機並沒有連接到網絡，所以在該種情況下Android設備無法使用網絡實現相關的網絡服務（比如關鍵數據的上傳，網絡數據的獲取等等），所以儀器在開始設計的時候將其作為客戶端，Android設備作為主機（網上的相關資料大多是將Android設備作為客戶端），當Android設備開啟熱點后，儀器會主動嘗試連接固定的熱點信息，其中網絡SSID和密碼已經寫死了，所以需要手機端手動修改熱點名稱：

在開啟熱點之后，此時手機相當於一個路由器，這個路由器的IP地址是固定的（本人測試過3台Android設備，其默認的路由器地址：192.168.43.1，iPhone的默認路由器地址：172.20.10.1），這個Demo主要實現的目標是Android設備客戶端發送信息，服務端接受到信息后再發送信息給客戶端。那么Android設備創建的SocketServer代碼如下：

只有一個按鈕，實現在線程中啟動相對應的服務，所以在這里就不上圖了，直接放代碼：

package com.example.socketserver;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import com.koushikdutta.async.callback.CompletedCallback;
import com.koushikdutta.async.http.WebSocket;
import com.koushikdutta.async.http.WebSocket.StringCallback;
import com.koushikdutta.async.http.libcore.RequestHeaders;
import com.koushikdutta.async.http.server.AsyncHttpServer;
import com.koushikdutta.async.http.server.AsyncHttpServer.WebSocketRequestCallback;
import com.koushikdutta.async.http.server.AsyncHttpServerRequest;
import com.koushikdutta.async.http.server.AsyncHttpServerResponse;
import com.koushikdutta.async.http.server.HttpServerRequestCallback;

public class MainActivity extends Activity {
    private Button btnStart;
    private ServerSocket serverSocket;
    private BufferedReader in;
    private PrintWriter out;
    private Handler hander = new Handler(){

        @Override
        public void handleMessage(Message msg) {
            // TODO Auto-generated method stub
            super.handleMessage(msg);
            String s = (String)msg.obj;
            Toast.makeText(MainActivity.this, s, Toast.LENGTH_LONG).show();
        }
        
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btnStart = (Button)findViewById(R.id.button1);
        btnStart.setOnClickListener(new View.OnClickListener() {
            
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                new ServerThread().start();//在新線程中啟動SocketServer...
            }
        });        
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
    @Override
    protected void onStop() {
        // TODO Auto-generated method stub
        super.onStop();

    }
    private class ServerThread extends Thread{

        @Override
        public void run() {
            // TODO Auto-generated method stub
            super.run();
            try {
//                serverSocket = new ServerSocket(50005);//默認的路由器地址為Address: 192.168.43.1
                serverSocket = new ServerSocket(5000);
                while (true) {
                    Socket clientSocket = serverSocket.accept();//阻塞等待處理...
                     String remoteIP = clientSocket.getInetAddress().getHostAddress();
                        int remotePort = clientSocket.getLocalPort();
                        System.out.println("A client connected. IP:" + remoteIP+ ", Port: " + remotePort);   
                    System.out.println("server: receiving.............");
                    // 獲得 client 端的輸入輸出流，為進行交互做准備
                    in = new BufferedReader(new InputStreamReader(
                            clientSocket.getInputStream()));
                    out = new PrintWriter(clientSocket.getOutputStream(), false);

                    // 獲得 client 端發送的數據
                    String tmp = in.readLine();
                    // String content = new String(tmp.getBytes("utf-8"));
                    System.out.println("Client message is: " + tmp);

                    // 向 client 端發送響應數據
                    out.println("Your message has been received successfully！.");

                    // 關閉各個流
                    out.close();
                    in.close();
                     Message message = hander.obtainMessage();
                     message.obj=tmp;
                     hander.sendMessage(message);
                     try {
                        Thread.sleep(100);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            
        }
        
    }
}

客戶端實現的代碼與網上相關的資料相差無幾，比較簡單：

package com.example.serverclient;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.net.Socket;
import java.net.UnknownHostException;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;

public class MainActivity extends Activity {
    private Button sendBtn,sendMessageBtn;
    private Socket socket;
    private PrintStream output;
    private BufferedInputStream bufferedInputStream;
    private ReadThread readThread;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        sendBtn = (Button) findViewById(R.id.button1);
        sendMessageBtn = (Button) findViewById(R.id.button2);
        sendBtn.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                new Thread(runnable).start();//開啟線程
            }
        });
        sendMessageBtn.setOnClickListener(new View.OnClickListener() {
            
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                 sendMessage("hello,i am from client message");
            }
        });
    }
    Runnable runnable = new Runnable() {
        
        @Override
        public void run() {
            // TODO Auto-generated method stub
            initClientSocket();
            readThread = new ReadThread();
            readThread.start();
        }
    };

    public void initClientSocket() {
        try {
            socket = new Socket("192.168.43.1", 5000);
            output = new PrintStream(socket.getOutputStream(), true, "gbk");

        } catch (UnknownHostException e) {
            // TODO Auto-generated catch block
            System.out.println("請檢查端口號是否為服務器IP");
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            System.out.println("服務器未開啟");
            e.printStackTrace();
        }
        output.println("this is the message from client");
    }
    public byte[] receiveData() {
        if (socket == null || socket.isClosed()) {
            try {
                socket = new Socket("192.168.43.1", 5000);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        byte[] data = null;
        if (socket.isConnected()) {
            try {
                bufferedInputStream = new BufferedInputStream(socket.getInputStream());
                data = new byte[bufferedInputStream.available()];
                bufferedInputStream.read(data);
            } catch (IOException e) {
                e.printStackTrace();
            }
        } else {
            data = new byte[1];
        }
        return data;
    }
    private void sendMessage(String str) {
        output.println(str);
    }

    public void closeSocket() {
        try {
            output.close();
            socket.close();
        } catch (IOException e) {
            System.out.println("error"+e);
        }
    }
    private class ReadThread extends Thread{

        @Override
        public void run() {
            // TODO Auto-generated method stub
            super.run();
            while (true) {
                byte[] data = receiveData();
                if (data.length > 1) {
                    System.out.println(new String(data));
                }
            }
        }
        
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}