Android app Login functionality

LogIn.java

package com.login.dplanner;
import java.util.ArrayList;

import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class LogIn extends Activity {
    EditText usernameEditText, passwordEditText;
    Button login, login_cancel;
    TextView registration;

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

        usernameEditText = (EditText) findViewById(R.id.UserName);
        passwordEditText = (EditText) findViewById(R.id.PasswordName);
        login = (Button) findViewById(R.id.loginButton);
        login_cancel = (Button) findViewById(R.id.loginClearButton);

        // Login Button Listener
        login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                /**
                 * Normal Condition try this
                 */
                // Intent i = new Intent(LogIn.this, MainPanel.class);
                // startActivity(i);
                // Toast.makeText(LogIn.this, "Login Successful",
                // Toast.LENGTH_SHORT).show();

                /**
                 * After Server part implementation following code will be taken
                 * away. This loging part will be done at the end part of development.
                 */
                if (loginCheck()) {
                    launchMainPanel();
                    Toast.makeText(LogIn.this, "Login Successful",
                            Toast.LENGTH_SHORT).show();
                    finish();
                }
            }
        });

        // Registration Button Listener
        registration = (TextView) findViewById(R.id.RegistrationButton);
        registration.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                Intent i1 = new Intent(LogIn.this, Registration.class);
                startActivity(i1);
                Toast.makeText(LogIn.this, "Registration", Toast.LENGTH_SHORT)
                        .show();
            }
        });

        // Cancel Button Listener
        login_cancel.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                usernameEditText.setText("");
                passwordEditText.setText("");
                Toast.makeText(LogIn.this, "Clear Text", Toast.LENGTH_SHORT)
                        .show();
            }
        });

    }

    private boolean loginCheck() {
        String user_name_email = this.usernameEditText.getText().toString()
                .trim();
        String password = this.passwordEditText.getText().toString().trim();

        if (isValidEmailAddress(user_name_email)) {
            if (isValidUser(user_name_email, password))
                return true;
            else
                return false;
        } else
            return false;
    }


    private void launchMainPanel() {
        Intent i = new Intent(this, MainPanel.class);
        startActivity(i);
    }


    private boolean isValidEmailAddress(String emailAddress) {
        /**
         * if mail address is NULL string
         */
        if (TextUtils.isEmpty(emailAddress)) {
            Toast.makeText(this, "Empty username", Toast.LENGTH_SHORT).show();
            usernameShake();
            return false;
        }
        // if mail address does NOT contain "@"
        if (!emailAddress.contains("@")) {
            Toast.makeText(this, "Invalid username", Toast.LENGTH_SHORT).show();
            usernameShake();
            return false;
        }
        /**
         * if mail address does NOT contain "."
         */
        if (!emailAddress.contains(".")) {
            Toast.makeText(this, "Invalid username", Toast.LENGTH_SHORT).show();
            usernameShake();
            return false;
        }

        /**
         * if number of characters after "." < 2
         */
        if (numberOfCharsAfterDot(emailAddress) == false) {
            Toast.makeText(this, "Invalid username", Toast.LENGTH_SHORT).show();
            usernameShake();
            return false;
        }
        return true;
    }
    private boolean isValidUser(String user_name_email, String password) {
        ArrayList<NameValuePair> loginParameters = new ArrayList<NameValuePair>();

        loginParameters.add(new BasicNameValuePair("username", usernameEditText
                .getText().toString()));
        loginParameters.add(new BasicNameValuePair("password", passwordEditText
                .getText().toString()));

        // String valid = "1";
        String response = null;
        try {
            response = HttpConnector.executeHttpPost(
                    "http://10.0.2.2/d_planner_project/d_planner_login.php",
                    loginParameters);

            String res = response.toString();
            // res = res.trim();
            res = res.replaceAll("\\s+", "");
            // error.setText(res);

            if (res.equals("1")) {
                Toast.makeText(this, "loading...", Toast.LENGTH_SHORT).show();
                return true;
            } else {
                usernameShake();
                passwordShake();
                Toast.makeText(this, "username or password incorrect",
                        Toast.LENGTH_SHORT).show();
                return false;
            }

        } catch (Exception e) {
            return false;
        }
    }

    private void usernameShake() {
        Animation shake = AnimationUtils.loadAnimation(this, R.anim.shake);
        findViewById(R.id.UserName).startAnimation(shake);
    }

    private void passwordShake() {
        Animation shake = AnimationUtils.loadAnimation(this, R.anim.shake);
        findViewById(R.id.PasswordName).startAnimation(shake);
    }




    private boolean numberOfCharsAfterDot(String emailAddress) {
        int a, b, c;
        char ch = '.';

        a = emailAddress.indexOf(ch);
        b = emailAddress.length();
        c = b - a;

        if (c == 3 || c == 4) { // here to exactly to confirm the number of
            // characters after "." = 2 OR 3
            return true;
        } else {
            return false;
        }
    }

    /**
     * Create and menu option button in the bottom of the screen
     */
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // getMenuInflater().inflate(R.menu.activity_login, menu);
        menu.add("Registration");
        return true;
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        Toast.makeText(this, "Registration", Toast.LENGTH_LONG).show();
        Intent i1 = new Intent(LogIn.this, Registration.class);
        startActivity(i1);
        return super.onOptionsItemSelected(item);
    }
}