package com.example.user.loginregister;

import android.app.AlertDialog;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;


public class Login extends ActionBarActivity implements    View.OnClickListener{

    Button bLogin;
    EditText etUsername, etPassword;
    TextView tvRegisterLink;
    UserLocalStore userLocalStore;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_login);

    etUsername = (EditText) findViewById(R.id.etUsername);
    etPassword = (EditText) findViewById(R.id.etPassword);
    bLogin = (Button) findViewById(R.id.bLogin);
    tvRegisterLink = (TextView) findViewById(R.id.tvRegisterlink);

    bLogin.setOnClickListener(this);
    tvRegisterLink.setOnClickListener(this);
    userLocalStore = new UserLocalStore(this);


   }

    private void authenticate(User user) {


    ServerRequests serverRequests = new ServerRequests(this);
    serverRequests.fetchUserDataInBackground(user, new GetUserCallBack()
    {

        @Override
        public void done(User returnedUser) {
            Toast.makeText(getApplicationContext(), (CharSequence)     returnedUser, Toast.LENGTH_LONG).show();
            if (returnedUser == null) {
                showErrorMessage();


            }else {

                logUserIn(returnedUser);
            }
        }
    });
    }

private void showErrorMessage(){

    AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(Login.this);
    dialogBuilder.setMessage("Incorrect user details");
    dialogBuilder.setPositiveButton("Ok", null);
    dialogBuilder.show();
    }
    private void logUserIn(User returnedUser) {

    userLocalStore.storeUserData(returnedUser);
    userLocalStore.setUserLoggedIn(true);

    startActivity(new Intent(this, MainActivity.class));
    }

    @Override
    public void onClick(View v) {
    switch (v.getId()) {
        case R.id.bLogin:
            String username = etUsername.getText().toString();
            String password = etPassword.getText().toString();


    User user = new User(username, password);
    Toast.makeText(getApplicationContext(), "this is my Toast message!!! =)",
        Toast.LENGTH_LONG).show();

authenticate(user);
   userLocalStore.storeUserData(user);
   userLocalStore.setUserLoggedIn(true);
            break;

        case R.id.tvRegisterlink:

            startActivity(new Intent(this, Register.class));


            break;
        }
    }


}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.user.loginregister" >

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


<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name=".MainActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
        android:name=".Login"
        android:label="@string/title_activity_login" >
    </activity>
    <activity
        android:name=".Register"
        android:label="@string/title_activity_register" >
    </activity>
    </application>

</manifest>

package com.example.user.loginregister;

import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;


public class MainActivity extends ActionBarActivity implements   View.OnClickListener{

    Button bLogout;
    EditText etUsername, etAge, etName;
    UserLocalStore userlocalStore;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    etUsername = (EditText)findViewById(R.id.etUsername);
    etName = (EditText)findViewById(R.id.etName);
    etAge = (EditText)findViewById(R.id.etAge);
    bLogout = (Button)findViewById(R.id.bLogout);

    bLogout.setOnClickListener(this);
    userlocalStore = new UserLocalStore(this);
    }

    @Override
    protected void onStart(){
    super.onStart();
    if(authenticate()==true){

        displayUserDetails();
      }else {

       startActivity(new Intent(MainActivity.this, Login.class));
    }
    }

    private boolean authenticate(){

    return userlocalStore.getUserLoggedIn();
    }

    private void displayUserDetails(){

    User user = userlocalStore.getLoggedInUser();

    etUsername.setText(user.username);
    etName.setText(user.name);
    etAge.setText(user.age + "");


    }


    @Override
    public void onClick(View v) {
    switch(v.getId()){

        case R.id.bLogout:

           userlocalStore.clearUserDate();
            userlocalStore.setUserLoggedIn(false);

            startActivity(new Intent(this, Login.class));

            break;
        }
    }
}

package com.example.user.loginregister;

import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;


public class Register extends ActionBarActivity implements View.OnClickListener{

    Button bRegister;
    EditText etUsername, etPassword, etAge, etName;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_register);

    etUsername = (EditText)findViewById(R.id.etUsername);
    etPassword = (EditText)findViewById(R.id.etPassword);
    etName = (EditText)findViewById(R.id.etName);
    etAge = (EditText)findViewById(R.id.etAge);
    bRegister = (Button)findViewById(R.id.bRegister);

    bRegister.setOnClickListener(this);

    }
    private void registerUser(User user){
    ServerRequests serverRequests = new ServerRequests(this);
        serverRequests.storeUserDataInBackground(user, new  GetUserCallBack()          {
            @Override
            public void done(User returnedUser) {

            startActivity(new Intent(Register.this, Login.class));

            }
        });

    }

    @Override
    public void onClick(View v) {
        switch(v.getId()){

            case R.id.bRegister:

            String name = etName.getText().toString();
            String username = etUsername.getText().toString();
            String password = etPassword.getText().toString();

                int age = Integer.parseInt(etAge.getText().toString());

                User user = new User(name, age, username, password);

               registerUser(user);



                break;
        }
    }


}

package com.example.user.loginregister;

import android.app.ProgressDialog;
import android.content.Context;
import android.os.AsyncTask;
import android.widget.Toast;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
import org.apache.http.util.EntityUtils;
import org.json.JSONObject;

import java.util.ArrayList;

/**
 * Created by user on 1/9/2016.
 */
public class ServerRequests {

    ProgressDialog progressDialog;
    public static final int CONNECTION_TIMEOUT = 1000 * 15;

    public static final String SERVER_ADDRESS = "http://192.168.1.2/";

    public ServerRequests(Context context) {

    progressDialog = new ProgressDialog(context);
    progressDialog.setCancelable(false);
    progressDialog.setTitle("Processing");
    progressDialog.setMessage("Please wait...");

    }

    public void storeUserDataInBackground(User user, GetUserCallBack  userCallBack) {

        progressDialog.show();
        new StoreUserDataAsyncTask(user,userCallBack).execute();

    }

    public void fetchUserDataInBackground(User user, GetUserCallBack userCallBack) {
        progressDialog.show();
        new fetchUserDataAsyncTask(user, userCallBack).execute();

    }

    public class StoreUserDataAsyncTask extends AsyncTask<Void, Void,  Void> {

        User user;
        GetUserCallBack userCallBack;

        public StoreUserDataAsyncTask(User user, GetUserCallBack userCallBack) {


        this.user = user;
        this.userCallBack = userCallBack;
    }

    @Override
    protected Void doInBackground(Void... params) {

        ArrayList<NameValuePair> dataToSend = new ArrayList<>();
        dataToSend.add(new BasicNameValuePair("name", user.name));
        dataToSend.add(new BasicNameValuePair("username", user.username));
        dataToSend.add(new BasicNameValuePair("password", user.password));
        dataToSend.add(new BasicNameValuePair("age", user.age + ""));


        HttpParams httpRequestParams = new BasicHttpParams();
        HttpConnectionParams.setConnectionTimeout(httpRequestParams, CONNECTION_TIMEOUT);
        HttpConnectionParams.setSoTimeout(httpRequestParams, CONNECTION_TIMEOUT);

        HttpClient client = new DefaultHttpClient(httpRequestParams);
        HttpPost post = new HttpPost(SERVER_ADDRESS + "Register.php");

        try {
            post.setEntity(new UrlEncodedFormEntity(dataToSend));

           client.execute(post);

        } catch (Exception e) {
            e.printStackTrace();

        }
        return null;
        }

        @Override
        protected void onPostExecute(Void aVoid) {

        progressDialog.dismiss();

            userCallBack.done(null);
            super.onPostExecute(aVoid);

        }
    }


    public class fetchUserDataAsyncTask extends AsyncTask<Void, Void, User> {

    User user;
    GetUserCallBack userCallBack;
    //User returnedUser ;

    public fetchUserDataAsyncTask(User user, GetUserCallBack userCallBack) {


        this.user = user;
        this.userCallBack = userCallBack;
    }

    @Override
    protected User doInBackground(Void... params) {

        ArrayList<NameValuePair> dataToSend = new ArrayList<>();

        dataToSend.add(new BasicNameValuePair("username", user.username));
        dataToSend.add(new BasicNameValuePair("password", user.password));

        HttpParams httpRequestParams = new BasicHttpParams();
        HttpConnectionParams.setConnectionTimeout(httpRequestParams, CONNECTION_TIMEOUT);
        HttpConnectionParams.setSoTimeout(httpRequestParams, CONNECTION_TIMEOUT);

        HttpClient client = new DefaultHttpClient(httpRequestParams);
        HttpPost post = new HttpPost(SERVER_ADDRESS + "FetchUserData.php");

           User returnedUser = null;
        try {
            post.setEntity(new UrlEncodedFormEntity(dataToSend));
            HttpResponse httpResponse = client.execute(post);
            HttpEntity entity = httpResponse.getEntity();
            String result = EntityUtils.toString(entity);
            JSONObject jObject = new JSONObject(result);

            if (jObject.length() == 0) {

                returnedUser = null;

            } else {

                String name = jObject.getString("name");
                int age = jObject.getInt("age");
                returnedUser = new User(name, age, user.username, user.password);


            }


        } catch (Exception e) {
            e.printStackTrace();

        }
        return returnedUser;

    }

        @Override
        protected void onPostExecute(User returnedUser) {

        progressDialog.dismiss();

            userCallBack.done(returnedUser);
            super.onPostExecute(returnedUser);

        }

    }
}

package com.example.user.loginregister;

/**
 * Created by user on 1/7/2016.
 */
public class User {
String name, username, password;
int age;

public User(String name, int age, String username, String password){

    this.name = name;
    this.age = age;
    this.username = username;
    this.password = password;

    }

    public User(String username, String password){


    this.username = username;
    this.password = password;
    this.age = -1;
    this.name = "";

    }
}

package com.example.user.loginregister;

import android.content.Context;
import android.content.SharedPreferences;

/**
 * Created by user on 1/7/2016.
 */
public class UserLocalStore {
    public static final String SP_NAME = "userDetails";
    SharedPreferences userLocalDatabase;

    public UserLocalStore(Context context){

    userLocalDatabase = context.getSharedPreferences(SP_NAME,0);

    }

    public void storeUserData(User user){

    SharedPreferences.Editor spEditor = userLocalDatabase.edit();
    spEditor.putString("name", user.name);
    spEditor.putString("username", user.username);
    spEditor.putString("password", user.password);
    spEditor.putInt("age", user.age);

    spEditor.commit();
    }

    public User getLoggedInUser(){

    String name = userLocalDatabase.getString("name", "");
    int age = userLocalDatabase.getInt("age", -1);
    String username = userLocalDatabase.getString("username", "");
    String password = userLocalDatabase.getString("password", "");

    User storedUser = new User(name, age, username, password);

    return storedUser;
   }

    public void setUserLoggedIn(boolean loggedIn){

    SharedPreferences.Editor spEditor = userLocalDatabase.edit();
    spEditor.putBoolean("loggedIn", loggedIn);
    spEditor.commit();
    }

    public boolean getUserLoggedIn(){

    if(userLocalDatabase.getBoolean("loggedIn", false)== true){

        return true;
    }else {

        return false;
    }
    }

    public void clearUserDate(){

    SharedPreferences.Editor spEditor = userLocalDatabase.edit();
    spEditor.clear();
    spEditor.commit();
    }


}

package com.example.user.loginregister;

/**
 * Created by user on 1/9/2016.
 */
interface GetUserCallBack {

public abstract void done(User returnedUser);
}

<?php

$con=mysqli_connect("localhost", "my_user", "my_password", "my_db");(security reason)

if (isset($_POST['name']))
{
  $name = $_POST['name']; // Instructions if $_POST['value'] exist
}

if (isset($_POST['username']))
{
 $username = $_POST['username']; // Instructions if $_POST['value'] exist
}
if (isset($_POST['password']))
{
 $password = $_POST['password']; // Instructions if $_POST['value'] exist
}
if (isset($_POST['age']))
{
$age = $_POST['age']; // Instructions if $_POST['value'] exist
}

$statement =  mysqli_prepare($con, "INSERT INTO User (name, age,  username, password) VALUES (?, ?, ?, ?)");
mysqli_stmt_bind_param($statement, "siss", $name, $age, $username,  $password);
mysqli_stmt_execute($statement);


mysqli_stmt_close($statement);
mysqli_close($con);

?>

<?php

 $con=mysqli_connect("localhost", "my_user", "my_password", "my_db"); (security reason)

if (isset($_POST['password']))
{
   $password = $_POST['password']; // Instructions if $_POST['value']  exist
}
if (isset($_POST['username']))
{
  $username = $_POST['username']; // Instructions if $_POST['value'] exist
}

$statement =  mysqli_prepare($con, "SELECT * FROM User WHERE username = ? AND password = ?");
mysqli_stmt_bind_param($statement, "ss", $username, $password);

mysqli_stmt_execute($statement);
mysqli_stmt_store_result($statement);
mysqli_stmt_bind_result($statement, $userID, $name, $age, $username, $password);

$user = array();
while(mysqli_stmt_fetch($statement)){

$user[name] = $name;
$user[age] = $age;
$user[username] = $username;
$user[password] = $password;
}
echo json_encode($user);
mysqli_stmt_close($statement);
mysqli_close($con);

?>