SimeGuiWithLoginDialog

package com.jana.gui;

import java.awt.Container;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;

public class MainWindow extends JFrame {

    private static final long serialVersionUID = 1L;

    // UI components

    private Container controls; // hlavny Container kde budes vkladas vsetko (nadpisy, tlacitka atď...)
    private JLabel title;
    private JMenuBar menubar;
    private JMenu login;
    private JMenuItem login_item;

    public MainWindow() {
        super("Add here your title");
        this.setSize(640, 480); // nadstavujes velkost okna
        this.setResizable(false); // ak to mas na true, mozes menit velkost okna tahanim mysou, inak nie
        centerWindow(); // vycentruje to na stred monitoru
        initMenu();
        init();
    }

    private void init() {
        controls = getContentPane(); // vrati Container okna
        controls.setLayout(new FlowLayout()); // nadstavis layout containera

        title = new JLabel("Lorem ipsum dolor sit amet");
        controls.add(title);
    }

    private void centerWindow() {
        Dimension d = Toolkit.getDefaultToolkit().getScreenSize();
        this.setLocation(d.width / 4, d.height / 6);
    }

    private void initMenu() {

        menubar = new JMenuBar();
        this.setJMenuBar(menubar);

        login = new JMenu("System");
        menubar.add(login);
        login_item = new JMenuItem("Login");
        login.add(login_item);
        login_item.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                LoginDialog d = new LoginDialog(MainWindow.this);
                d.setVisible(true);
            }
        });
    }
}












package com.jana.gui;

import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
import javax.swing.SwingConstants;

public class LoginDialog extends JDialog {

    private static final long serialVersionUID = 1L;

    private MainWindow parent;
    private Container controls;
    private JTextField login, password;
    private JLabel loginLabel, passwordLabel;
    private JButton loginBtn;

    public LoginDialog(MainWindow parent) {
        super(parent, "Login into System");
        this.parent = parent;
        this.setSize(350, 180);
        this.setResizable(false);
        this.setLocationRelativeTo(parent);
        init();
    }

    private void init() {
        controls = getContentPane();
        controls.setLayout(new GridBagLayout());

        GridBagConstraints c = new GridBagConstraints();

        c.gridx = 0;
        c.gridy = 0;
        loginLabel = new JLabel("Login:");
        loginLabel.setAlignmentX(SwingConstants.RIGHT);
        controls.add(loginLabel, c);

        c.gridx = 1;
        c.gridy = 0;
        c.insets = new Insets(0, 0, 5, 0);
        login = new JTextField(15);
        login.setText("admin");
        login.setEnabled(false);
        controls.add(login, c);

        c.gridx = 0;
        c.gridy = 1;
        passwordLabel = new JLabel("Password:");
        controls.add(passwordLabel, c);

        c.gridx = 1;
        c.gridy = 1;
        password = new JTextField(15);
        controls.add(password, c);

        c.gridx = 0;
        c.gridy = 2;
        c.fill = GridBagConstraints.VERTICAL;
        loginBtn = new JButton("Login");
        controls.add(loginBtn, c);
        loginBtn.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                if (password.getText().length() > 0) {
                    String pass = password.getText();
                    if (pass.equals("admin")) {
                        close();
                        Toolkit.getDefaultToolkit().beep(); // zvuk
                        JOptionPane.showMessageDialog(parent, "You are successfully logged in!", "Information", JOptionPane.INFORMATION_MESSAGE);
                    }
                    else {
                        Toolkit.getDefaultToolkit().beep();
                        JOptionPane.showMessageDialog(parent, "Invalid password! Try it again.", "Error", JOptionPane.ERROR_MESSAGE);
                    }
                }
                else {
                    Toolkit.getDefaultToolkit().beep();
                    JOptionPane.showMessageDialog(parent, "Password field cannot be empty!", "Warning", JOptionPane.WARNING_MESSAGE);
                }
            }
        });
    }

    private void close() {
        this.dispose();
    }
}






package com.jana.launcher;

import javax.swing.SwingUtilities;

import com.jana.gui.MainWindow;

public class Main {

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() { // GUI je odporucane spustat vo vlakne
            @Override
            public void run() {
                MainWindow mw = new MainWindow();
                mw.setVisible(true);
            }
        });
    }
}