Android MySQL登录和注册不起作用。 意外的响应代码500

Question

I'm following this tutorial: http://www.androidhive.info/2012/01/android-login-and-registration-with-php-mysql-and-sqlite/ Copy-pasted the php files, only changed the database parameters and the amount of data user table stores. Whenever I try to register a user, I get this in my logcat:

03-31 14:07:04.694 11972-12241/com.example.giedrius.keliokliuciuregistravimosistema E/Volley: [192] BasicNetwork.performRequest: Unexpected response code 500 for http://giekri.stud.if.ktu.lt/register.php
03-31 14:07:04.746 11972-11972/com.example.giedrius.keliokliuciuregistravimosistema E/RegistrationScreen: Registration Error: null

My AppConfig:

package com.example.giedrius.keliokliuciuregistravimosistema;
public class AppConfig {
    // Server user login url
    public static String URL_LOGIN = "http://giekri.stud.if.ktu.lt/login.php";

    // Server user register url
    public static String URL_REGISTER = "http://giekri.stud.if.ktu.lt/register.php";
}

AppController unchanged:

package com.example.giedrius.keliokliuciuregistravimosistema;

import android.app.Application;
import android.text.TextUtils;

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

public class AppController extends Application {

    public static final String TAG = AppController.class.getSimpleName();

    private RequestQueue mRequestQueue;

    private static AppController mInstance;

    @Override
    public void onCreate() {
        super.onCreate();
        mInstance = this;
    }

    public static synchronized AppController getInstance() {
        return mInstance;
    }

    public RequestQueue getRequestQueue() {
        if (mRequestQueue == null) {
            mRequestQueue = Volley.newRequestQueue(getApplicationContext());
        }

        return mRequestQueue;
    }

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

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

    public void cancelPendingRequests(Object tag) {
        if (mRequestQueue != null) {
            mRequestQueue.cancelAll(tag);
        }
    }
}

And Registration file:

package com.example.giedrius.keliokliuciuregistravimosistema;

import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import com.android.volley.Request.Method;
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;

import com.example.giedrius.keliokliuciuregistravimosistema.R;
import com.example.giedrius.keliokliuciuregistravimosistema.AppConfig;
import com.example.giedrius.keliokliuciuregistravimosistema.AppController;
import com.example.giedrius.keliokliuciuregistravimosistema.SQLiteHandler;
import com.example.giedrius.keliokliuciuregistravimosistema.SessionManager;

public class RegistrationScreen extends Activity {
    private static final String TAG = RegistrationScreen.class.getSimpleName();
    private Button btnRegister;
    private Button btnLinkToLogin;
    private EditText inputFullName;
    private EditText inputFullSurname;
    private EditText inputAddress;
    private EditText inputEmail;
    private EditText inputPassword;
    private EditText inputPassword2;
    private ProgressDialog pDialog;
    private SessionManager session;
    private SQLiteHandler db;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_registration_screen);

        inputFullName = (EditText) findViewById(R.id.et_Vardas);
        inputFullSurname = (EditText) findViewById(R.id.et_Pavarde);
        inputAddress = (EditText) findViewById(R.id.et_Adresas);
        inputEmail = (EditText) findViewById(R.id.et_elPastas);
        inputPassword = (EditText) findViewById(R.id.et_Slaptazodis);
        inputPassword2 = (EditText) findViewById(R.id.et_Slaptazodis2);
        btnRegister = (Button) findViewById(R.id.bt_Registruotis);
        btnLinkToLogin = (Button) findViewById(R.id.bt_Prisijungti);

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

        // Session manager
        session = new SessionManager(getApplicationContext());

        // SQLite database handler
        db = new SQLiteHandler(getApplicationContext());

        // Check if user is already logged in or not
        if (session.isLoggedIn()) {
            // User is already logged in. Take him to main activity
            Intent intent = new Intent(RegistrationScreen.this,
                    MainMenu.class);
            startActivity(intent);
            finish();
        }

        // Register Button Click event
        btnRegister.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                String name = inputFullName.getText().toString().trim();
                String surname = inputFullName.getText().toString().trim();
                String address = inputFullName.getText().toString().trim();
                String email = inputEmail.getText().toString().trim();
                String password = inputPassword.getText().toString().trim();
                String password2 = inputPassword2.getText().toString().trim();



                if (!name.isEmpty() && !surname.isEmpty() && !address.isEmpty() && !email.isEmpty() && !password.isEmpty() && !password2.isEmpty()) {
                    registerUser(name, surname, address, email, password);
                } else {
                    Toast.makeText(getApplicationContext(),
                            "Please enter your details correctly!", Toast.LENGTH_LONG)
                            .show();
                }
            }
        });

        // Link to Login Screen
        btnLinkToLogin.setOnClickListener(new View.OnClickListener() {

            public void onClick(View view) {
                Intent i = new Intent(getApplicationContext(),
                        LoginScreen.class);
                startActivity(i);
                finish();
            }
        });

    }

    /**
     * Function to store user in MySQL database will post params(tag, name,
     * email, password) to register url
     * */
    private void registerUser(final String name, final String surname, final String address, final String email, final String password) {
        // Tag used to cancel the request
        String tag_string_req = "req_register";

        pDialog.setMessage("Registering ...");
        showDialog();

        StringRequest strReq = new StringRequest(Method.POST, AppConfig.URL_REGISTER, 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) {
                        // User successfully stored in MySQL
                        // Now store the user in sqlite
                        JSONObject user = jObj.getJSONObject("user");
                        String name = user.getString("name");
                        String surname = user.getString("surname");
                        String address = user.getString("address");
                        String email = user.getString("email");

                        // Inserting row in users table
                        db.addUser(name, surname, address, email);

                        Toast.makeText(getApplicationContext(), "User successfully registered. Try login now!", Toast.LENGTH_LONG).show();

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

                        // Error occurred in registration. Get the error
                        // message
                        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("surname", surname);
                params.put("address", address);
                params.put("email", email);
                params.put("password", password);

                return params;
            }

        };

        // Adding request to request queue
        AppController.getInstance().addToRequestQueue(strReq, tag_string_req);
    }

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

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

I have tried to debug it and it looks to get messed up in this part:

StringRequest strReq = new StringRequest(Method.POST, AppConfig.URL_REGISTER, new Response.Listener<String>()

it jumps through everything in the curly brackets right to

AppController.getInstance().addToRequestQueue(strReq, tag_string_req);

Does anyone have any idea what's going on? I can provide the rest of the files if needed.

EDIT Addint Registration php file:

<?php

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

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

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

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

    // check if user with the same email already exists
    if ($db->doesUserExist($email)) {
        // user already exists
        $response["error"] = TRUE;
        $response["error_msg"] = "User already exists with email: " . $email;
        echo json_encode($response);
    } else {
        // create a new user
        $user = $db->storeUser($name, $surname, $address, $email, $password);
        if ($user) {
            // user stored successfully
            $response["error"] = FALSE;
            $response["user"]["name"] = $user["name"];
            $response["user"]["surname"] = $user["surname"];
            $response["user"]["address"] = $user["address"];
            $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;
    $response["error_msg"] = "Required parameters (name, surname, address, email or password) is missing!";
    echo json_encode($response);
}
?>

P.S. The URLs should be working, because I used them in another login tutorial and it worked fine. But it had only the login part, so I moved to this tutorial which also has registration. And now it doesn't work. The tutorial which worked is this