Java Swing Меню и панели инструментов

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Создаем menubar

Menubar это одна из многих составляющих кашерного приложения с GUI, хотя люди, придумавшие слово "кашерный" могут со мной не согласиться. Сразу же приношу им свои изменения. Что же до menubar, сие есть сгрупированный набор команд. В то время как при использовании консольного приложения вы должны были запоминать все эти загадочные команды (странно, а я думал, что загадочным линуксоидам нравится запоминать загадочные команды и от этого становиться еще более загадочными - прим. переводчика), здесь мы имеем множество команд логично сгрупированных в одном месте по категориям. Все это позволяет существенно уменьшить временные затраты на освоение нового, незнакомого ранее, приложения пользователем. В Java Swing для реализации menubar используются три компонента. Имя им JMenuBar, JMenu и JMenuItem. Ниже вы ощутите их ужасающую мощь, сильнее которой лишь загадочность консоли.

Простой menubar

Итак, начнем с простого примера menubar. 

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
 
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.UIManager;
 
 
public class Menu extends JFrame {
 
    public Menu() {
 
        setTitle("JMenuBar");
 
        JMenuBar menubar = new JMenuBar();
        ImageIcon icon = new ImageIcon("exit.png");
 
        JMenu file = new JMenu("File");
        file.setMnemonic(KeyEvent.VK_F);
 
        JMenuItem fileClose = new JMenuItem("Close", icon);
        fileClose.setMnemonic(KeyEvent.VK_C);
        fileClose.setToolTipText("Exit application");
        fileClose.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                System.exit(0);
 
        });
 
        file.add(fileClose);
 
        menubar.add(file);
 
        setJMenuBar(menubar);
 
        setSize(250, 200);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
    }
 
    public static void main(String[] args) {
 
        new Menu();
 
    }
}


Наш пример демонстрирует menubar с одним элементом. Выбрав элемент "Close" мы закроем приложение (завершим его работу). 

 JMenuBar menubar = new JMenuBar();

Здесь мы создаем menubar. 

 ImageIcon icon = new ImageIcon("exit.png");

Отобразим иконку в меню. 

 JMenu file = new JMenu("File");
 file.setMnemonic(KeyEvent.VK_F);

Создадим объект меню. Можно также быстро получить доступ к пунктам меню посредством клавиатуры. Для назначения элементу меню специальной клавиши, мы используем метод setMnemonic. В нашем случае, меню может быть открыто с помощью сочетания клавиш ALT + F. 


 fileClose.setToolTipText("Exit application");

В этой строке мы создаем всплывающую подсказку для элемента меню.



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Submenu (подпункты меню)

Каждое меню может иметь произвольное количество субменю. Таким образом мы можем объеденять схожие по смыслу команды в группы. Например, мы можем поместить команды, которые скрывают/показывают различные toolbars like personal bar, address bar, status bar or navigation bar into a submenu called toolbars. Within a menu, we can seperate commands with a separator. It is a simple line. It is common practice to separate commands like new, open, save from commands like print, print preview with a single separator. Menus commands can be launched via keyboard shortcuts. For this, we define menu item accelerators. 


import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
 
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.KeyStroke;
 
 
public class Submenu extends JFrame {
 
    public Submenu() {
 
        setTitle("Submenu");
 
        JMenuBar menubar = new JMenuBar();
        ImageIcon iconNew = new ImageIcon("new.png");
        ImageIcon iconOpen = new ImageIcon("open.png");
        ImageIcon iconSave = new ImageIcon("save.png");
        ImageIcon iconClose = new ImageIcon("exit.png");
 
        JMenu file = new JMenu("File");
        file.setMnemonic(KeyEvent.VK_F);
 
        JMenu imp = new JMenu("Import");
        imp.setMnemonic(KeyEvent.VK_M);
 
        JMenuItem newsf = new JMenuItem("Import newsfeed list...");
        JMenuItem bookm = new JMenuItem("Import bookmarks...");
        JMenuItem mail = new JMenuItem("Import mail...");
 
        imp.add(newsf);
        imp.add(bookm);
        imp.add(mail);
 
        JMenuItem fileNew = new JMenuItem("New", iconNew);
        fileNew.setMnemonic(KeyEvent.VK_N);
 
        JMenuItem fileOpen = new JMenuItem("Open", iconOpen);
        fileNew.setMnemonic(KeyEvent.VK_O);
 
        JMenuItem fileSave = new JMenuItem("Save", iconSave);
        fileSave.setMnemonic(KeyEvent.VK_S);     
 
        JMenuItem fileClose = new JMenuItem("Close", iconClose);
        fileClose.setMnemonic(KeyEvent.VK_C);
        fileClose.setToolTipText("Exit application");
        fileClose.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_W, 
            ActionEvent.CTRL_MASK));
 
        fileClose.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                System.exit(0);   
            }
 
        });
 
        file.add(fileNew);
        file.add(fileOpen);
        file.add(fileSave);
        file.addSeparator();
        file.add(imp);
        file.addSeparator();
        file.add(fileClose);
 
        menubar.add(file);
 
        setJMenuBar(menubar);
 
        setSize(360, 250);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
    }
 
    public static void main(String[] args) {
        new Submenu();
    }
}

In this example, we create a submenu, a menu separator and an accelerator key. 

 JMenu imp = new JMenu("Import");
 ...
 file.add(imp);

A submenu is just like any other normal menu. It is created the same way. We simply add a menu to existing menu. 

 fileClose.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_W, 
     ActionEvent.CTRL_MASK));

An accelerator is a key shortcut that launches a menu item. In our case, by pressing Ctrl + W we close the application. 


 file.addSeparator();

A separator is a vertical line that visually separates the menu items. This way we can group items into some logical places.

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JCheckBoxMenuItem

A menu item that can be selected or deselected. If selected, the menu item typically appears with a checkmark next to it. If unselected or deselected, the menu item appears without a checkmark. Like a regular menu item, a check box menu item can have either text or a graphic icon associated with it, or both. 

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
 
import javax.swing.BorderFactory;
import javax.swing.JCheckBoxMenuItem;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.UIManager;
import javax.swing.border.EtchedBorder;
 
 
public class CheckMenuItem extends JFrame {
 
 
    private JLabel statusbar;
 
    public CheckMenuItem() {
 
        setTitle("CheckBoxMenuItem");
 
        JMenuBar menubar = new JMenuBar();
        JMenu file = new JMenu("File");
        file.setMnemonic(KeyEvent.VK_F);
 
        JMenu view = new JMenu("View");
        view.setMnemonic(KeyEvent.VK_V);
 
        JCheckBoxMenuItem sbar = new JCheckBoxMenuItem("Show StatuBar");
        sbar.setState(true);
 
        sbar.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                if (statusbar.isVisible()) {
                    statusbar.setVisible(false);
                } else {
                    statusbar.setVisible(true);
                }
            }
 
        });
 
        view.add(sbar);
 
        menubar.add(file);
        menubar.add(view);
 
        setJMenuBar(menubar);
 
        statusbar = new JLabel(" Statusbar");
        statusbar.setBorder(BorderFactory.createEtchedBorder(
		EtchedBorder.RAISED));
        add(statusbar, BorderLayout.SOUTH);
 
 
        setSize(360, 250);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
    }
 
    public static void main(String[] args) {
        new CheckMenuItem(); 
    }
}

The example shows a JCheckBoxMenuItem.. By selecting the menu item, we toggle the visibility of the statusbar. 

 JCheckBoxMenuItem sbar = new JCheckBoxMenuItem("Show StatuBar");
 sbar.setState(true);

We create the JCheckBoxMenuItem and check it by default. The statusbar is initially visible. 

 if (statusbar.isVisible()) {
	 statusbar.setVisible(false);
 } else {
	 statusbar.setVisible(true);
 }

Here we toggle the visibility of the statusbar. 

 statusbar = new JLabel(" Statusbar");
 statusbar.setBorder(BorderFactory.createEtchedBorder(EtchedBorder.RAISED));

The statusbar is a simple JLabel component. We put a raised EtchedBorder around the label, so that it is discernible.

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A popup menu

Another type of a menu is a popup menu. It is sometimes called a context menu. It is usually shown, when we right click on a component. The idea is to provide only the commands, that are relevant to the current context. Say we have an image. By right clicking on the image, we get a window with commands to save, rescale, move etc the image. 


import java.awt.Toolkit;
 
import javax.swing.*;
import java.awt.event.*;
 
public class PopupMenu {
 
    private JPopupMenu menu;
    private Toolkit toolkit;
 
  public PopupMenu(){
 
 
    JFrame frame = new JFrame("JPopupMenu");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
    toolkit = frame.getToolkit();
 
    menu = new JPopupMenu();
    JMenuItem menuItemBeep = new JMenuItem("Beep");
 
    menuItemBeep.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            toolkit.beep();
        }
    });
 
    menu.add(menuItemBeep);
 
    JMenuItem menuItemClose = new JMenuItem("Close");
    menuItemClose.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            System.exit(0);
        }
 
    });
 
    menu.add(menuItemClose);
 
    frame.addMouseListener(new MouseAdapter() {
        public void mouseReleased(MouseEvent e) {
            if (e.getButton() == e.BUTTON3) {
                menu.show(e.getComponent(), e.getX(), e.getY());
            }
        }
    });
 
    frame.setSize(250, 200);
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
  }
 
 
 
  public static void main(String[] args) {
        new PopupMenu();
  }
}

Our example shows a demonstrational popup menu with two commands. The first option of the popup menu will beep a sound, the second one will close the window.

In our example, we create a submenu, menu separators and create an accelerator key. 

 menu = new JPopupMenu();

To create a popup menu, we have a class called JPopupMenu. 

 JMenuItem menuItemBeep = new JMenuItem("Beep");

The menu item is the same, as with the standard JMenu 

 frame.addMouseListener(new MouseAdapter() {
     public void mouseReleased(MouseEvent e) {
         if (e.getButton() == e.BUTTON3) {
             menu.show(e.getComponent(), e.getX(), e.getY());
         }
     }
 });

The popup menu is shown, where we clicked with the mouse button. The BUTTON3 constant is here to enable the popup menu only for the mouse right click.

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JToolbar

Menus group commands that we can use in an application. Toolbars provide a quick access to the most frequently used commands. In Java Swing, the JToolBar class creates a toolbar in an application. 

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
 
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JToolBar;
 
 
public class SimpleToolbar extends JFrame {
 
 
    public SimpleToolbar() {
 
        setTitle("SimpleToolbar");
 
        JMenuBar menubar = new JMenuBar();
        JMenu file = new JMenu("File");
        menubar.add(file);
        setJMenuBar(menubar);
 
        JToolBar toolbar = new JToolBar();
 
        ImageIcon icon = new ImageIcon(getClass().getResource("exit.png"));
 
        JButton exit = new JButton(icon);
        toolbar.add(exit);
        exit.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                System.exit(0);
            }
 
        });
 
 
        add(toolbar, BorderLayout.NORTH);
 
        setSize(300, 200);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
    }
 
    public static void main(String[] args) {
        new SimpleToolbar();
    }
}


The example creates a toolbar with one exit button. 

 JToolBar toolbar = new JToolBar();

This is the JToolBar constructor. 

 JButton exit = new JButton(icon);
 toolbar.add(exit);

We create a button and add it to the toolbar.

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Toolbars

Say, we wanted to create two toolbars. The next example shows, how we could do it. 


import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
 
import javax.swing.BoxLayout;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JToolBar;
 
 
public class Toolbars extends JFrame {
 
    public Toolbars() {
 
        setTitle("Toolbars");
 
        JToolBar toolbar1 = new JToolBar();
        JToolBar toolbar2 = new JToolBar();
 
        JPanel panel = new JPanel();
        panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
 
        ImageIcon newi = new ImageIcon(
		getClass().getResource("new.png"));
        ImageIcon open = new ImageIcon(
		getClass().getResource("open.png"));
        ImageIcon save = new ImageIcon(
		getClass().getResource("save.png"));
        ImageIcon exit = new ImageIcon(
		getClass().getResource("exit.png"));
 
        JButton newb = new JButton(newi);
        JButton openb = new JButton(open);
        JButton saveb = new JButton(save);
 
        toolbar1.add(newb);
        toolbar1.add(openb);
        toolbar1.add(saveb);
        toolbar1.setAlignmentX(0);
 
        JButton exitb = new JButton(exit);
        toolbar2.add(exitb); 
        toolbar2.setAlignmentX(0);
 
        exitb.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                System.exit(0);
            }
 
        });
 
        panel.add(toolbar1);
        panel.add(toolbar2);
 
        add(panel, BorderLayout.NORTH);
 
        setSize(300, 200);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
    }
 
    public static void main(String[] args) {
        new Toolbars();
    }
}

We show only one way, how we could create toolbars. Of course, there are several possibilities. We put a JPanel to the north of the BorderLayout manager. The panel has a vertical BoxLayout. We add the two toolbars into this panel. 

 JToolBar toolbar1 = new JToolBar();
 JToolBar toolbar2 = new JToolBar();

Creation of two toolbars. 

 JPanel panel = new JPanel();
 panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));

The panel has a vertical BoxLayout. 


 toolbar1.setAlignmentX(0);

The toolbar is left aligned. 


 panel.add(toolbar1);
 panel.add(toolbar2);
 
 add(panel, BorderLayout.NORTH);

We add the toolbars to the panel. Finally, the panel is located into the north part of the frame.

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A vertical toobar

The following example shows a vertical toobar. 


import java.awt.BorderLayout;
 
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JToolBar;
import javax.swing.UIManager;
 
 
public class VerticalToolbar extends JFrame {
 
 
    public VerticalToolbar() {
 
        setTitle("Vertical toolbar");
 
        JToolBar toolbar = new JToolBar(JToolBar.VERTICAL);
 
        ImageIcon select = new ImageIcon(
		getClass().getResource("select.gif"));
        ImageIcon freehand = new ImageIcon(
		getClass().getResource("freehand.gif"));
        ImageIcon shapeed = new ImageIcon(
		getClass().getResource("shapeed.gif"));
        ImageIcon pen = new ImageIcon(
		getClass().getResource("pen.gif"));
        ImageIcon rectangle = new ImageIcon(
		getClass().getResource("rectangle.gif"));
        ImageIcon ellipse = new ImageIcon(
		getClass().getResource("ellipse.gif"));
        ImageIcon qs = new ImageIcon(
		getClass().getResource("qs.gif"));
        ImageIcon text = new ImageIcon(
		getClass().getResource("text.gif"));
 
        JButton selectb = new JButton(select);
        JButton freehandb = new JButton(freehand);
        JButton shapeedb = new JButton(shapeed);
        JButton penb = new JButton(pen);
        JButton rectangleb = new JButton(rectangle);
        JButton ellipseb = new JButton(ellipse);
        JButton qsb = new JButton(qs);
        JButton textb = new JButton(text);
 
        toolbar.add(selectb);
        toolbar.add(freehandb);
        toolbar.add(shapeedb);
        toolbar.add(penb);
        toolbar.add(rectangleb);
        toolbar.add(ellipseb);
        toolbar.add(qsb);
        toolbar.add(textb);
 
        add(toolbar, BorderLayout.WEST);
 
        setSize(250, 350);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
    }
 
    public static void main(String[] args) {
        try {
            UIManager.setLookAndFeel(
                UIManager.getSystemLookAndFeelClassName());
        } 
        catch (Exception e) {
            System.out.println("Error:" + e.getStackTrace());
        }
        new VerticalToolbar();
    }
}

In the example, we put a vertical toolbar to the left side of the window. This is typical for a graphics applications like Xara Extreme or Inkscape. In our example, we use icons from Xara Extreme application. 

 JToolBar toolbar = new JToolBar(JToolBar.VERTICAL);

We create a vertical toolbar. 

 add(toolbar, BorderLayout.WEST);

The toolbar is placed into the left part of the window. 

 UIManager.setLookAndFeel(
     UIManager.getSystemLookAndFeelClassName());

I used the system look and feel. In my case, it was the gtk theme. The icons are not transparent, and they would not look ok on a different theme.

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Источник — «http://wiki.crossplatform.ru/index.php?title=Java_Swing_%D0%9C%D0%B5%D0%BD%D1%8E_%D0%B8_%D0%BF%D0%B0%D0%BD%D0%B5%D0%BB%D0%B8_%D0%B8%D0%BD%D1%81%D1%82%D1%80%D1%83%D0%BC%D0%B5%D0%BD%D1%82%D0%BE%D0%B2»