Android: client-server, user authentication -

i have never built such android application communicate sever. want want send username , password server, match them on server , when username , password matches next screen should shown. next screen should have 1 text view saying "welcome username".

i want guys tell me step step guide -

1. what should write in android app?
2. what should write on server side?
3. how , write server code?
4. which language should use server side?
5. how save several usernames-passwords on server?

i don't have real server. run entire code on localhost.

update:

this wrote in android app. don't know how correct.

public void clicked(view v) {     system.out.println("button clicked");     edittext username = (edittext) findviewbyid(r.id.edituser);     edittext password = (edittext) findviewbyid(r.id.editpass);      editable user = username.gettext();     editable pass = password.gettext();      httpclient httpclient = new defaulthttpclient();     httppost httppost = new httppost("http://192.168.1.101:8080//webapplication1/sendresponse.java");      try {         // add data         list<namevaluepair> namevaluepairs = new arraylist<namevaluepair>(2);         namevaluepairs.add(new basicnamevaluepair("username", user.tostring()));         namevaluepairs.add(new basicnamevaluepair("password", pass.tostring()));         httppost.setentity(new urlencodedformentity(namevaluepairs));          // execute http post request         httpresponse response = httpclient.execute(httppost);          header[] headers = response.getallheaders();         int len = headers.length;         for(int i=0; i<len; i++) {             system.out.println("header : " + headers[i]);         }          inputstream inputstream = response.getentity().getcontent();          inputstreamreader inputstreamreader = new inputstreamreader(inputstream);          bufferedreader bufferedreader = new bufferedreader(inputstreamreader);          stringbuilder stringbuilder = new stringbuilder();          string bufferedstrchunk = null;          while((bufferedstrchunk = bufferedreader.readline()) != null){             stringbuilder.append(bufferedstrchunk);         }         system.out.println("response : " + stringbuilder.tostring());      } catch (clientprotocolexception e) {         // todo auto-generated catch block     } catch (ioexception e) {         // todo auto-generated catch block     }    } 

i don't know language best server side. should use rest on server side?

i'll authenticate using php. first of all,

 httppost httppost = new httppost("http://10.0.2.2/login.php"); 

10.0.2.2 reffers localhost emulator. real device, need real server.

you have create db & table @ localhost using phpmyadmin.(assuming using wamp/lamp)

now, php file this:

   <?php  $link=mysql_connect('localhost','root','password');// give username & password if (!$link) {      die('could not connect mysql: ' . mysql_error());  }   mysql_select_db("database_name");  $sql=mysql_query("select * login_table_name user_name = '".$_request['username']."' , password = '".$_request['password']."'"); if (mysql_num_rows($sql) > 0) {  echo "success"; }else{ echo "login failed";  } mysql_close($link);  ?> 

(assuming know put php file, localhost)(www folder wamp/lamp)

now, coming java, leave steps upto line is. , change code here to

httpresponse response = httpclient.execute(httppost); httpentity entity=response.getentity(); string res=entityutils.tostring(entity); if(res.contains("success")){ //login success } else{ //loginfailed } 

now can how store usernames , passwords. yes, create registration form, wrap namevaluepairs , send php in sql query change 'insert into'.

nb: if run on emulator api-14+, exception- network on main thread exception. have use asynvtask. try in api-10.

edit:

if need values server, encode json , send. changes as,

php

if(mysql_num_rows($sql)>0){     while($row=mysql_fetch_assoc($sql)){// can use either fetch_assoc or fetch_array     $result[]=$row;     } echo json_encode($result); } 

java

string res=entityutils.tostring(entity); log.d("tag","from server:"+res);// see server sent if( ! res.contains("login failed")){ jsonarray jarray = new jsonarray(res);  if(jarray!=null){             for(int i=0;i<jarray.length();i++){                 jsonobject jobj = jarray.getjsonobject(i);                 //now, catch values using column_name. as, id=jobj.getint("_id");name= jobj.getstring("name"); //note here _id,name column names. refer server result in logcat better understanding             } }  }