import android.content.Context;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.toolbox.Volley;

public class AppSingleton {
    private static AppSingleton mAppSingletonInstance;
    private RequestQueue mRequestQueue;
    private static Context mContext;

private AppSingleton(Context context) {
    mContext = context;
    mRequestQueue = getRequestQueue();
}

public static synchronized AppSingleton getInstance(Context context) {
    if (mAppSingletonInstance == null) {
        mAppSingletonInstance = new AppSingleton(context);
    }
    return mAppSingletonInstance;
}

public RequestQueue getRequestQueue() {
    if (mRequestQueue == null) {
        // getApplicationContext() is key, it keeps you from leaking the
        // Activity or BroadcastReceiver if someone passes one in.
        mRequestQueue = Volley.newRequestQueue(mContext.getApplicationContext());
    }
    return mRequestQueue;
}

public <T> void addToRequestQueue(Request<T> req,String tag) {
    req.setTag(tag);
    getRequestQueue().add(req);
}
}

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioGroup;
import android.widget.Toast;
import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.HashMap;
import java.util.Map;

public class Main_formulario_docente extends Activity {

private static final String TAG = "RegisterActivity";
private static final String URL_FOR_REGISTRATION = "http://192.168.0.110/android_login_v2/register.php";
ProgressDialog progressDialog;

private EditText signupInputName, signupInputEmail, signupInputPassword, signupInputPassword2, signupInputAge;
private Button btnSignUp;
private Button btnLinkLogin;
private RadioGroup genderRadioGroup;

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

    // Progress dialog
    progressDialog = new ProgressDialog(this);
    progressDialog.setCancelable(false);

    signupInputName = (EditText) findViewById(R.id.name);
    signupInputEmail = (EditText) findViewById(R.id.email);
    signupInputPassword = (EditText) findViewById(R.id.password);
    signupInputPassword2 = (EditText) findViewById(R.id.password2);
    //signupInputAge = (EditText) findViewById(R.id.signup_input_age);

    btnSignUp = (Button) findViewById(R.id.btnRegister);
    btnLinkLogin = (Button) findViewById(R.id.btnLinkToLoginScreen);

    //genderRadioGroup = (RadioGroup) findViewById(R.id.gender_radio_group);
    btnSignUp.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            submitForm();
        }
    });
    btnLinkLogin.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            Intent i = new Intent(getApplicationContext(),Main_docente.class);
            startActivity(i);
            finish();
        }
    });
}

private void submitForm() {
    registerUser(signupInputName.getText().toString(),
            signupInputEmail.getText().toString(),
            signupInputPassword.getText().toString());
}

private void registerUser(final String name,  final String email, final String password) {
    // Tag used to cancel the request
    String cancel_req_tag = "register";

    progressDialog.setMessage("Registrando ...");
    showDialog();

    StringRequest strReq = new StringRequest(Request.Method.POST,
            URL_FOR_REGISTRATION, new Response.Listener<String>() {

        @Override
        public void onResponse(String response) {
            Log.d(TAG, "Register Response: " + response.toString());
            hideDialog();

            try {
                JSONObject jObj = new JSONObject(response);
                boolean error = jObj.getBoolean("error");

                if (!error) {
                    String user = jObj.getJSONObject("user").getString("name");
                    Toast.makeText(getApplicationContext(), "Hi " + user +", You are successfully Added!", Toast.LENGTH_SHORT).show();

                    // Launch login activity
                    Intent intent = new Intent(
                            Main_formulario_docente.this, Main_docente.class);
                    startActivity(intent);
                    finish();
                } else {

                    String errorMsg = jObj.getString("error_msg");
                    Toast.makeText(getApplicationContext(),
                            errorMsg, Toast.LENGTH_LONG).show();
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }

        }
    }, new Response.ErrorListener() {

        @Override
        public void onErrorResponse(VolleyError error) {
            Log.e(TAG, "Registration Error: " + error.getMessage());
            Toast.makeText(getApplicationContext(),
                    error.getMessage(), Toast.LENGTH_LONG).show();
            hideDialog();
        }
    }) {
        @Override
        protected Map<String, String> getParams() {
            // Posting params to register url
            Map<String, String> params = new HashMap<String, String>();
            params.put("name", name);
            params.put("email", email);
            params.put("password", password);
            //params.put("gender", gender);
            //params.put("age", dob);
            return params;
        }
    };
    // Adding request to request queue
    AppSingleton.getInstance(getApplicationContext()).addToRequestQueue(strReq, cancel_req_tag);
}

private void showDialog() {
    if (!progressDialog.isShowing())
        progressDialog.show();
}

private void hideDialog() {
    if (progressDialog.isShowing())
        progressDialog.dismiss();
}

}

import android.app.Activity;
import android.app.ProgressDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.Button;
import android.widget.EditText;
import android.content.Intent;
import android.view.View;
import android.widget.Toast;
import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.HashMap;
import java.util.Map;


public class Main_docente extends Activity {
private static final String TAG = "LoginActivity";
private static final String URL_FOR_LOGIN = "http://192.168.0.110/android_login_v2/login.php";
ProgressDialog progressDialog;
private EditText loginInputEmail, loginInputPassword;
private Button btnlogin;
private Button btnLinkSignup;

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


    loginInputEmail = (EditText) findViewById(R.id.email);
    loginInputPassword = (EditText) findViewById(R.id.password);
    btnlogin = (Button) findViewById(R.id.btnLogin);
    btnLinkSignup = (Button) findViewById(R.id.btnLinkToRegisterScreen);
    // Progress dialog
    progressDialog = new ProgressDialog(this);
    progressDialog.setCancelable(false);

    btnlogin.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            loginUser(loginInputEmail.getText().toString(), loginInputPassword.getText().toString());
        }
    });

    btnLinkSignup.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent i = new Intent(getApplicationContext(), Main_formulario_docente.class);
            startActivity(i);
        }
    });
}

private void loginUser( final String email, final String password) {
    // Tag used to cancel the request
    String cancel_req_tag = "login";
    progressDialog.setMessage("Logging you in...");
    showDialog();
    StringRequest strReq = new StringRequest(Request.Method.POST,
            URL_FOR_LOGIN, new Response.Listener<String>() {

        @Override
        public void onResponse(String response) {
            Log.d(TAG, "Register Response: " + response.toString());
            hideDialog();
            try {
                JSONObject jObj = new JSONObject(response);
                boolean error = jObj.getBoolean("error");

                if (!error) {
                    String user = jObj.getJSONObject("user").getString("name");
                    // Launch User activity
                    Intent intent = new Intent(
                            Main_docente.this, MainActivity.class);
                    intent.putExtra("username", user);
                    startActivity(intent);
                    finish();
                } else {

                    String errorMsg = jObj.getString("error_msg");
                    Toast.makeText(getApplicationContext(),
                            errorMsg, Toast.LENGTH_LONG).show();
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }

        }
    }, new Response.ErrorListener() {

        @Override
        public void onErrorResponse(VolleyError error) {
            Log.e(TAG, "Login Error: " + error.getMessage());
            Toast.makeText(getApplicationContext(),
                    error.getMessage(), Toast.LENGTH_LONG).show();
            hideDialog();
        }
    }) {

        @Override
        protected Map<String, String> getParams() {
            // Posting params to login url
            Map<String, String> params = new HashMap<String, String>();
            params.put("email", email);
            params.put("password", password);
            return params;
        }

    };
    // Adding request to request queue
    AppSingleton.getInstance(getApplicationContext()).addToRequestQueue(strReq,cancel_req_tag);
}

private void showDialog() {
    if (!progressDialog.isShowing())
        progressDialog.show();
}
private void hideDialog() {
    if (progressDialog.isShowing())
        progressDialog.dismiss();
}

}

<?php

define("DB_HOST", "localhost");
define("DB_USER", "root");
define("DB_PASSWORD", "12345");
define("DB_DATABASE", "android_login");

?>

<?php
class android_login_connect {
private $conn;

// Connecting to database
public function connect() {
    require_once 'android_login_config.php';

    // Connecting to mysql database
    $this->conn = new mysqli(DB_HOST, DB_USER, DB_PASSWORD, DB_DATABASE);
    // return database object
    return $this->conn;
}
}

?>

<?php
require_once 'update_user_info.php';
$db = new update_user_info();

// json response array
$response = array("error" => FALSE);

if (isset($_POST['email']) && isset($_POST['password'])) {

// receiving the post params
$email = $_POST['email'];
$password = $_POST['password'];

// get the user by email and password
$user = $db->VerifyUserAuthentication($email, $password);

if ($user != false) {
    // use is found
    $response["error"] = FALSE;
    $response["user"]["name"] = $user["name"];
    $response["user"]["email"] = $user["email"];
    echo json_encode($response);
} else {
    // user is not found with the credentials
    $response["error"] = TRUE;
    $response["error_msg"] = "Login credentials are wrong. Please try
again!";
    echo json_encode($response);
}
} else {
// required post params is missing
$response["error"] = TRUE;
$response["error_msg"] = "Required parameters email or password is
missing!";
echo json_encode($response);
}
?>

<?php

require_once 'update_user_info.php';
$db = new update_user_info();

// json response array
$response = array("error" => FALSE);

if (isset($_POST['name']) && isset($_POST['email']) &&
isset($_POST['password'])) {

// receiving the post params
$name = $_POST['name'];
$email = $_POST['email'];
$password = $_POST['password'];

// check if user is already existed with the same email
if ($db->CheckExistingUser($email)) {
    // user already existed
    $response["error"] = TRUE;
    $response["error_msg"] = "User already existed with " . $email;
    echo json_encode($response);
} else {
    // create a new user
    $user = $db->StoreUserInfo($name, $email, $password);
    if ($user) {
        // user stored successfully
        $response["error"] = FALSE;
        $response["user"]["name"] = $user["name"];
        $response["user"]["email"] = $user["email"];
        echo json_encode($response);
    } else {
        // user failed to store
        $response["error"] = TRUE;
        $response["error_msg"] = "Unknown error occurred in registration!";
        echo json_encode($response);
    }
}
} else {
$response["error"] = TRUE;
$response["error_msg"] = "Required parameters (name, email or password) is
missing!";
echo json_encode($response);
}
?>

<?php

class update_user_info {

private $conn;

// constructor
function __construct() {
    require_once 'android_login_connect.php';
    // connecting to database
    $db = new android_login_connect();
    $this->conn = $db->connect();
}

// destructor
function __destruct() {

}

/**
 * Storing new user
 * returns user details
 */
public function StoreUserInfo($name, $email, $password) {
    $hash = $this->hashFunction($password);
    $encrypted_password = $hash["encrypted"]; // encrypted password
    $salt = $hash["salt"]; // salt

    $stmt = $this->conn->prepare("INSERT INTO android_php_post(name, email,
encrypted_password, salt) VALUES(?, ?, ?, ?)");
    $stmt->bind_param("ssssss", $name, $email, $encrypted_password, $salt);
    $result = $stmt->execute();
    $stmt->close();

    // check for successful store
    if ($result) {
        $stmt = $this->conn->prepare("SELECT name, email,
encrypted_password, salt FROM android_php_post WHERE email = ?");
        $stmt->bind_param("s", $email);
        $stmt->execute();
        $stmt-> bind_result($token2,$token3,$token4,$token5);
        while ( $stmt-> fetch() ) {
           $user["name"] = $token2;
           $user["email"] = $token3;
        }
        $stmt->close();
        return $user;
    } else {
      return false;
    }
}

/**
 * Get user by email and password
 */
public function VerifyUserAuthentication($email, $password) {

    $stmt = $this->conn->prepare("SELECT name, email, encrypted_password,
salt FROM android_php_post WHERE email = ?");

    $stmt->bind_param("s", $email);

    if ($stmt->execute()) {
        $stmt-> bind_result($token2,$token3,$token4,$token5);

        while ( $stmt-> fetch() ) {
           $user["name"] = $token2;
           $user["email"] = $token3;
           $user["encrypted_password"] = $token4;
           $user["salt"] = $token5;
        }

        $stmt->close();

        // verifying user password
        $salt = $token5;
        $encrypted_password = $token4;
        $hash = $this->CheckHashFunction($salt, $password);
        // check for password equality
        if ($encrypted_password == $hash) {
            // user authentication details are correct
            return $user;
        }
    } else {
        return NULL;
    }
}

/**
 * Check user is existed or not
 */
public function CheckExistingUser($email) {
    $stmt = $this->conn->prepare("SELECT email from android_php_post WHERE
email = ?");

    $stmt->bind_param("s", $email);

    $stmt->execute();

    $stmt->store_result();

    if ($stmt->num_rows > 0) {
        // user existed
        $stmt->close();
        return true;
    } else {
        // user not existed
        $stmt->close();
        return false;
    }
}

/**
 * Encrypting password
 * @param password
 * returns salt and encrypted password
 */
public function hashFunction($password) {

    $salt = sha1(rand());
    $salt = substr($salt, 0, 10);
    $encrypted = base64_encode(sha1($password . $salt, true) . $salt);
    $hash = array("salt" => $salt, "encrypted" => $encrypted);
    return $hash;
}

/**
 * Decrypting password
 * @param salt, password
 * returns hash string
 */
public function checkHashFunction($salt, $password) {
    $hash = base64_encode(sha1($password . $salt, true) . $salt);
    return $hash;
}

}

?>

04-21 08:27:41.036 24791-24791/joinder.proyecto W/System.err:
org.json.JSONException: Value <br of type java.lang.String cannot be
converted to JSONObject
04-21 08:27:41.041 24791-24791/joinder.proyecto W/System.err:     at
org.json.JSON.typeMismatch(JSON.java:111)
04-21 08:27:41.042 24791-24791/joinder.proyecto W/System.err:     at
org.json.JSONObject.<init>(JSONObject.java:160)
04-21 08:27:41.042 24791-24791/joinder.proyecto W/System.err:     at
org.json.JSONObject.<init>(JSONObject.java:173)
04-21 08:27:41.042 24791-24791/joinder.proyecto W/System.err:     at
joinder.proyecto.Main_formulario_docente$3.onResponse
(Main_formulario_docente.j
ava:93)
04-21 08:27:41.042 24791-24791/joinder.proyecto W/System.err:     at
joinder.proyecto.Main_formulario_docente$3.onResponse
(Main_formulario_docente.java:85)
04-21 08:27:41.042 24791-24791/joinder.proyecto W/System.err:     at
com.android.volley.toolbox.StringRequest.deliverResponse
(StringRequest.java:60)
04-21 08:27:41.042 24791-24791/joinder.proyecto W/System.err:     at
com.android.volley.toolbox.StringRequest.deliverResponse
(StringRequest.java:30)
04-21 08:27:41.042 24791-24791/joinder.proyecto W/System.err:     at
com.android.volley.ExecutorDelivery$ResponseDeliveryRunnable.run
(ExecutorDelivery.java:99)
04-21 08:27:41.042 24791-24791/joinder.proyecto W/System.err:     at
android.os.Handler.handleCallback(Handler.java:739)
04-21 08:27:41.042 24791-24791/joinder.proyecto W/System.err:     at
android.os.Handler.dispatchMessage(Handler.java:95)
04-21 08:27:41.042 24791-24791/joinder.proyecto W/System.err:     at
android.os.Looper.loop(Looper.java:135)