android Socket实现简单聊天小程序
服务器端：
package org.hwq.echo;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.PrintWriter;import java.net.ServerSocket;import java.net.Socket;public class TalkServer { public static void main(String[] args) throws IOException{ ServerSocket server = null; Socket client = null; BufferedReader in = null; PrintWriter out = null; try{ server = new ServerSocket(4700); client = server.accept(); out = new PrintWriter(client.getOutputStream()); in = new BufferedReader(new InputStreamReader(client.getInputStream())); String line = in.readLine(); while(!"bye".equals(line)){ System.out.println("client:"+line); out.println("echo:"+line); out.flush(); line = in.readLine(); } }catch (Exception e) { e.printStackTrace(); if(client !=null) client.close(); if(server != null) server.close(); } }}手机端：
package org.hwq.cho;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.PrintWriter;import java.net.Socket;import java.net.UnknownHostException;import android.app.Activity;import android.content.Context;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;public class EchoActivity extends Activity implements OnClickListener { EditText show,msg; Button send; Handler handler; Socket client; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); handler = new MyHandler(); show = (EditText) findViewById(R.id.show); msg = (EditText) findViewById(R.id.msg); send = (Button) findViewById(R.id.send); send.setOnClickListener(this); } @Override public void onClick(View arg0) { String message = msg.getText().toString();// System.out.println("msg:"+message); new EchoThread(EchoActivity.this,message).start(); } public class MyHandler extends Handler{ @Override public void handleMessage(Message msg) { switch(msg.what){ case 1: Toast.makeText(EchoActivity.this, "建立连接失败", 0).show(); break; case 2: String message = (String) msg.obj; System.out.println("Handler:"+message); show.append("\n"+message); break; } } } private class EchoThread extends Thread{ private Context context; private String msg; EchoThread(Context context,String msg){ this.context = context; this.msg = msg; } public void run(){ if(client == null){ try { client = new Socket("192.168.1.102",4700); } catch (IOException e) { Message message = new Message(); message.what = 1; handler.sendMessage(message); } } System.out.println("建立连接"); try{ BufferedReader in; BufferedReader input; PrintWriter out; in = new BufferedReader(new InputStreamReader(client.getInputStream())); out = new PrintWriter(client.getOutputStream()); String line = msg; if(!"bye".equals(line)){ System.out.println("line:"+line); out.println(line); out.flush(); String echo = in.readLine(); System.out.println("server:"+echo); Message message = new Message(); message.obj = echo; message.what = 2; handler.sendMessage(message); } }catch (Exception e) { } } }}注意几点：
1、添加网络权限
<uses-permission android:name="android.permission.INTERNET"/>
如果没添加，无法使用socket连接网络。
2、在新启线程中不要使用android系统UI界面
在EchoThrad的run()方法里面，有下面代码：
if(client == null){ try { client = new Socket("192.168.1.102",4700); } catch (IOException e) { Message message = new Message(); message.what = 1; handler.sendMessage(message); } }这里的handler.sendMessage(message);是发送一个消息给handler,然后handler根据消息弹出一个Toast显示连接失败。如果这里直接使用
Toast.makeText(EchoActivity.this, "建立连接失败", 0).show();
会报如下错：
Can't create handler inside thread that has not called Looper.prepare()