android使用socket实现简单的点对点通信

要用android实现点对点通信,可以使用socket完成,使用socket需要知道对方的IP地址以及端口号,这里我省略了服务器端(编写正规的通信软件还是得需要服务器做中转,用服务器得知A的IP地址,然后让A做服务器端,B用A的Ip地址去获取数据),只是展示相关原理,首先看服务器端

package polly.liu;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.util.Enumeration;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.widget.TextView;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.widget.TextView;

public class ServerActivity extends Activity {
   ServerSocket ss = null;
   String mClientMsg = "";
   Thread myCommsThread = null;
   protected static final int MSG_ID = 0x1337;
   public static final int SERVERPORT = 6000;

   @Override
   public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    TextView tv = (TextView) findViewById(R.id.TextView01);
    tv.setText("Nothing from client yet");
    this.myCommsThread = new Thread(new CommsThread());
    this.myCommsThread.start();
   }

   @Override
   protected void onStop() {
    super.onStop();
    try {
        // 确保你退出时要关闭socket连接
        ss.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
   }

   Handler myUpdateHandler = new Handler() {
    public void handleMessage(Message msg) {
        switch (msg.what) {
        case MSG_ID:
            TextView tv = (TextView) findViewById(R.id.TextView01);
            tv.setText(mClientMsg);
            break;
        default:
            break;
        }
        super.handleMessage(msg);
    }
   };
   class CommsThread implements Runnable {
    public void run() {
        Socket s = null;
        try {
            ss = new ServerSocket(SERVERPORT );
        } catch (IOException e) {
            e.printStackTrace();
        }
        while (!Thread.currentThread().isInterrupted()) {
            Message m = new Message();
            m.what = MSG_ID;
            try {
                if (s == null)
                    s = ss.accept();
                BufferedReader input = new BufferedReader(new InputStreamReader(s.getInputStream()));
                String st = null;
                st = input.readLine();
                mClientMsg = st;
                myUpdateHandler.sendMessage(m);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    }
}

服务器端和平时在PC上的代码差不多,只不过现在把在PC上的代码转到了手机端,注意耗时间的操作要放在子线程上去做,再来看看客户端代码:

package polly.liu;

import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;

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

public class ClientActivity extends Activity {
   private Button bt;
   private TextView tv;
   private Socket socket;
   private String serverIpAddress = "192.168.1.104";

   private static final int REDIRECTED_SERVERPORT = 6000;
   @Override
   public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.main);
      bt = (Button) findViewById(R.id.myButton);
      tv = (TextView) findViewById(R.id.myTextView);
      try {
         InetAddress serverAddr = InetAddress.getByName(serverIpAddress);
         socket = new Socket(serverAddr, REDIRECTED_SERVERPORT);
      } catch (UnknownHostException e1) {
         e1.printStackTrace();
      } catch (IOException e1) {
         e1.printStackTrace();
      }
      bt.setOnClickListener(new OnClickListener() {
         public void onClick(View v) {
            try {
               EditText et = (EditText) findViewById(R.id.EditText01);
               String str = et.getText().toString();
               PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())),true);
               out.println(str);
               Log.d("Client", "Client sent message");
            } catch (UnknownHostException e) {
               tv.setText("Error1");
               e.printStackTrace();
            } catch (IOException e) {
               tv.setText("Error2");
               e.printStackTrace();
            } catch (Exception e) {
               tv.setText("Error3");
               e.printStackTrace();
            }
         }
      });
   }
}

注意要在manifest中加入权限

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

IP地址也需要根据情况去改