利用wifi在同一个局域网下实现两部手机之间的通讯

需要用到的权限

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

service端

public class MainActivity extends Activity {
	private Button start = null;
	private EditText bufferText = null;
	private Button send = null; 
	private ServerThread serverThread = null;
	private String sendBuffer = null;
	private String receiveBuffer = null;
	private TcpSocketServer tss = null;
	private TextView receiveView = null;

	private Handler handler = new Handler(){//线程与UI交互更新界面
		public void handleMessage(Message msg){			  
			receiveView.setText(receiveBuffer);
			Toast.makeText(MainActivity.this, receiveBuffer, Toast.LENGTH_SHORT).show();
		}
	};
	private String intToIp(int i) {                    
		return (i & 0xFF ) + "." +          
				((i >> 8 ) & 0xFF) + "." +           
				((i >> 16 ) & 0xFF) + "." +            
				( i >> 24 & 0xFF) ;   
	}
	protected void onCreate(Bundle savedInstanceState) {		
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		//获取wifi服务       
		WifiManager wifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);
		//判断wifi是否开启      
		if (!wifiManager.isWifiEnabled()) {        
			wifiManager.setWifiEnabled(true);         
		}       
		WifiInfo wifiInfo = wifiManager.getConnectionInfo();            
		int ipAddress = wifiInfo.getIpAddress();         
		String ip = intToIp(ipAddress);
		TextView tv=(TextView) findViewById(R.id.ip);
		tv.setText("本机IP："+ip);
		receiveView = (TextView)this.findViewById(R.id.receiveID);
		start = (Button) this.findViewById(R.id.startID);

		//监听服务器开启
		start.setOnClickListener(new OnClickListener() {
			public void onClick(View arg0) {				
				if(serverThread == null){
					EditText portEditText = (EditText)MainActivity.this.findViewById(R.id.portID);
					String port = portEditText.getText().toString().trim(); 
					serverThread = new ServerThread(port);
					serverThread .start();				
					Toast.makeText(MainActivity.this, port, Toast.LENGTH_SHORT).show();
				}							
			}});


		send = (Button)this.findViewById(R.id.sendID);
		bufferText = (EditText)this.findViewById(R.id.bufferID);

		//监听发送信息
		send.setOnClickListener(new OnClickListener() {						
			public void onClick(View v){
				sendBuffer = bufferText.getText().toString().trim(); 
				if(sendBuffer != null)//为了避免线程把它弄为buffer = null;
					Toast.makeText(MainActivity.this, sendBuffer, Toast.LENGTH_SHORT).show();
			} 
		}); 
	} 
	class ServerThread extends Thread{
		private int port;
		public ServerThread (String port){
			this.port = Integer.parseInt(port);  		
		}
		public void run(){
			//建立服务端
			if(tss == null)
				tss = new TcpSocketServer(this.port);
			new Thread(new WriteThread()).start();//开启“写”线程
			new Thread(new ReadThread()).start();//开启“读”线程
		}
		private class ReadThread implements Runnable{

			public void run(){			
				while(true){
					if((receiveBuffer = tss.getMessage()) != null){//收到不为null的信息就发送出去
						handler.sendEmptyMessage(0);						
					}
				}
			}
		}
		private class WriteThread implements Runnable{
			public void run(){
				while(true){
					try {
						//发送数据
						if(sendBuffer != null){
							//tss.sendMessage(1821,buffer);
							tss.sendMessage(sendBuffer);
							sendBuffer = null;//清空，不让它连续发
						}								
					} catch (Exception e) {
						e.printStackTrace();
					}	
				}
			}
		}
	}
}

public class TcpSocketServer {
	private ServerSocket ss =null;	
	private Socket s = null;
	private OutputStream out = null;
	private InputStream  in  = null;
	private String receiveBuffer = null; 
	public TcpSocketServer(int port){
		//新建ServerSocket对象,端口为传进来的port;		
		try {
			//ss= new ServerSocket(1821);
			System.out.print("no");
			ss = new ServerSocket(port);
			System.out.print("yes");
			s = ss.accept();
			out = s.getOutputStream();
			in  = s.getInputStream(); 
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	public void sendMessage(String buffer)throws Exception{
		//新建Socket通信对象，接受客户端发来的请求accept();
		//Socket s = ss.accept();
		//创建输入流对象InputStream
		InputStream bais = new ByteArrayInputStream(buffer.getBytes());		
		byte[] buff = new byte[1024];		
		bais.read(buff);
		out.write(buff);
		out.flush();						
	}
	public String getMessage(){
		byte[] temp = new byte[1024];
		try{
			if(in.read(temp) > 0)
			{
				return receiveBuffer = new String(temp).trim();				
			}} catch (IOException e) {			
			e.printStackTrace();
		}
		return null;
	}
	public String receiveMessage(){
		return null;
	}
}

client端

public class MainActivity extends Activity {

	private EditText ipEdit 	 = null;
	private EditText portEdit 	 = null;
	private EditText buffEdit 	 = null;
	private Button   startButton = null;
	private Button   sendButton  = null;
	private TextView receiveView = null;
	private Socket s = null;	
	private byte[] receiveBuffer = new byte[1024];
	private String sendBuffer = new String();
	private String ip = null;
	private int port ;
	private int cmdCount = 0; 
	  
	private Handler handler = new Handler(){//线程与UI交互更新界面
		public void handleMessage(Message msg){			  
			receiveView.setText(new String(receiveBuffer).trim());
			Arrays.fill(receiveBuffer, (byte)0);//清空
		}
	};
	

	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);				 		
		
		this.init();
		/*开启socket通信*/
		startButton.setOnClickListener(new OnClickListener() {					
			public void onClick(View v) {			
				if(s == null){//这里要设置验证!!!!!!!!!	
					/*设定ip和port*/
					ip = ipEdit.getText().toString();
					port = Integer.parseInt(portEdit.getText().toString());
					/*开启socket线程*/
					new Thread(new SocketClientControl(ip,port)).start();					
				}								
				Toast.makeText(MainActivity.this, "服务器连接成功", Toast.LENGTH_SHORT).show();
			} 
		}); 		
		/*发送数据*/
		sendButton.setOnClickListener(new OnClickListener(){					
			public void onClick(View v) {
				if(s != null)
					sendBuffer = buffEdit.getText().toString();
					Toast.makeText(MainActivity.this, "send -> "+sendBuffer, Toast.LENGTH_SHORT).show();
				}							
			}); 
	}		
	private void init(){
		startButton = (Button) this.findViewById(R.id.startID);
		sendButton  = (Button) this.findViewById(R.id.sendID);
		ipEdit 	    = (EditText) this.findViewById(R.id.ipID);
		portEdit 	= (EditText) this.findViewById(R.id.portID);
		buffEdit 	= (EditText) this.findViewById(R.id.buffID);		 
		receiveView = (TextView) this.findViewById(R.id.recieiveID);
	}
	private class SocketClientControl implements Runnable{
		private InputStream  in  = null;
		private OutputStream out = null;
		public SocketClientControl(){
			
		}
		public SocketClientControl(String ip,int port){
			try { 
				s = new Socket(ip,port);//获得链接
				in  = s.getInputStream();//获得输入流
				out = s.getOutputStream();//获得输出流
			} catch (IOException e) { 
				e.printStackTrace();
				System.exit(-1);//要是出问题，就线程退出
			}			 			
		}
		public void run(){
			new Thread(new WriteThread()).start();//开启“写”线程
			new Thread(new ReadThread()).start();//开启“读”线程
		}
		private class ReadThread implements Runnable{			
			public void run() {
				while(true){
					try {					 
						if(in.read(receiveBuffer) > 0){//等待命令的输入
							cmdCount ++;				;
							handler.sendEmptyMessage(0);//发送信息，更新UI										
						}						
					} catch (IOException e) {
						e.printStackTrace();					
					}
				}
			}			
		}		
		private class WriteThread implements Runnable{
		
			public void run(){
				while(true){				
					if(!sendBuffer.equals("")){
						try {
							out.write(sendBuffer.getBytes());//输出
							out.flush();//输出刷新缓冲
						} catch (IOException e) {
							e.printStackTrace();
						}			
						sendBuffer = "";
					} 
				}													
			}
			
		}

	}
}

public class SocketClientSingle {
	private static Socket s = null;
	private SocketClientSingle()
	{
		
	}
	public static Socket getSocket(String ip,int port){
		try {
			s = new Socket(ip,port);
		} catch (UnknownHostException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return s; 
	}

}