Android Socket Communication Programming instance code

The Android client communicates with the server by using a socket to be divided into the following steps:

There are two modes of communication between application and server: TCP reliable communication and UDP unreliable communication.

(1) Instantiate the socket via IP address and port and request the connection server:

The code is as follows	Copy Code
Socket = new Socket (HOST, PORT); Host: Port for server IP address: port number for server

(2) Get the socket stream to read and write, and wrap the stream into Bufferwriter or printwriter:

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PrintWriter out = new PrintWriter (new BufferedWriter (New OutputStreamWriter (Socket.getoutputstream)), true);

Here are three classes: Socket.getoutputstream get socket output byte throttling, OutputStreamWriter is a stream of bytes to the character streams conversion bridge, Bufferwriter is the character streams, and then packaged into PrintWriter.

(3) Read and write to the socket

code is as follows	copy code
if (socket.isconnected ()) {                      if (!socket.isoutputshutdown ()) {                           out.println (msg);                     }                }

(4) Close the open stream

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Out.close ();

Here's a simple demo of how to implement socket communication with Android:

Server programs
The server program needs to run on the PC, the program is simpler, so there's no need to build an Android project, define a Java class directly, and run the class. It only establishes ServerSocket listening and uses a socket to get the input output stream.

The code is as follows

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Import java.io.IOException; Import Java.io.OutputStream; Import Java.net.ServerSocket; Import Java.net.Socket; public class Simpleserver { /** * @param args * @throws IOException */ public static void Main (string[] args) throws IOException { TODO auto-generated Method Stub Create a ServerSocket to listen for connection requests for client sockets ServerSocket ss=new ServerSocket (30000); The use of loops to accept requests from the client, the server side also corresponds to the production of a socket while (true) { Socket s=ss.accept (); OutputStream Os=s.getoutputstream (); Os.write ("Hello, you have received the New Year's Greetings from the server!" N ". GetBytes (" Utf-8 ")); Os.close (); S.close (); } }}

Client programs

The code is as follows

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Package my.learn.tcp; Import Java.io.BufferedReader; Import java.io.IOException; Import Java.io.InputStreamReader; Import Java.net.Socket; Import java.net.UnknownHostException; Import android.app.Activity; Import Android.os.Bundle; Import Android.util.Log; Import Android.widget.EditText; public class SimpleClient extends activity { Private EditText Show; @Override protected void OnCreate (Bundle savedinstancestate) { TODO auto-generated Method Stub Super.oncreate (savedinstancestate); Setcontentview (R.layout.main); Show = (edittext) Findviewbyid (r.id.show); try { Socket socket = new socket ("IP address of your own computer", 30000); 10 seconds after setting is considered a timeout Socket.setsotimeout (10000); BufferedReader br = new BufferedReader (New InputStreamReader ( Socket.getinputstream ())); String line = Br.readline (); Show.settext ("Data from the server:" +line); Br.close (); Socket.close (); catch (Unknownhostexception e) { TODO auto-generated Catch block LOG.E ("Unknownhost", "Data from the server"); E.printstacktrace (); catch (IOException e) { LOG.E ("IOException", "Data from the server"); TODO auto-generated Catch block E.printstacktrace (); } } }

In addition, in the Manifest.xml file, access to the Internet is required to authorize:

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

In the process of writing code must pay attention to the socket input stream to the output stream shutdown