[Java Swing] JMenu trong Java
Định viết bài về JMenu tuy nhiên khi tìm được bài code này thì nó rất đầy đủ, giải thích cũng tương đối rõ ràng.
Trước tiên chúng ta cần add một MenuBar vào JFrame, sau đó các JMenu được add vào MenuBar, các JMenuItem được add vào các JMenu.
Chương trình có cả JPopupmenu (khi click chuột phải).
Ngoài ra các bạn cần có ảnh làm icon trong menu, copy file ảnh vào trong package như thế này:
001 002 003 004 005 006 007 008 009 010 011 012 013 014 015 016 017 018 019 020 021 022 023 024 025 026 027 028 029 030 031 032 033 034 035 036 037 038 039 040 041 042 043 044 045 046 047 048 049 050 051 052 053 054 055 056 057 058 059 060 061 062 063 064 065 066 067 068 069 070 071 072 073 074 075 076 077 078 079 080 081 082 083 084 085 086 087 088 089 090 091 092 093 094 095 096 097 098 099 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 | package nguyenvanquan7826.JMenu;import java.awt.BorderLayout;import java.awt.Container;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.awt.event.ItemEvent;import java.awt.event.ItemListener;import java.awt.event.KeyEvent;import java.awt.event.MouseAdapter;import java.awt.event.MouseEvent;import java.awt.event.MouseListener;import javax.swing.ButtonGroup;import javax.swing.ImageIcon;import javax.swing.JCheckBoxMenuItem;import javax.swing.JFrame;import javax.swing.JMenu;import javax.swing.JMenuBar;import javax.swing.JMenuItem;import javax.swing.JPanel;import javax.swing.JPopupMenu;import javax.swing.JRadioButtonMenuItem;import javax.swing.JScrollPane;import javax.swing.JTextArea;import javax.swing.KeyStroke;/* DemoRightClickMenu.java requires images/middle.gif. *//* * Like MenuDemo, but with popup menus added. */public class DemoJMenu implements ActionListener, ItemListener { JTextArea output; JScrollPane scrollPane; String newline = "\n"; public JMenuBar createMenuBar() { JMenuBar menuBar; JMenu menu, submenu; JMenuItem menuItem; JRadioButtonMenuItem rbMenuItem; JCheckBoxMenuItem cbMenuItem; // Create the menu bar. menuBar = new JMenuBar(); // Build the first menu. menu = new JMenu("A Menu"); menu.setMnemonic(KeyEvent.VK_A); menu.getAccessibleContext().setAccessibleDescription( "The only menu in this program that has menu items"); menuBar.add(menu); // a group of JMenuItems menuItem = new JMenuItem("A text-only menu item", KeyEvent.VK_T); // menuItem.setMnemonic(KeyEvent.VK_T); //used constructor instead menuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_1, ActionEvent.ALT_MASK)); menuItem.getAccessibleContext().setAccessibleDescription( "This doesn't really do anything"); menuItem.addActionListener(this); menu.add(menuItem); ImageIcon icon = createImageIcon("images/middle.gif"); menuItem = new JMenuItem("Both text and icon", icon); menuItem.setMnemonic(KeyEvent.VK_B); menuItem.addActionListener(this); menu.add(menuItem); menuItem = new JMenuItem(icon); menuItem.setMnemonic(KeyEvent.VK_D); menuItem.addActionListener(this); menu.add(menuItem); // a group of radio button menu items menu.addSeparator(); ButtonGroup group = new ButtonGroup(); rbMenuItem = new JRadioButtonMenuItem("A radio button menu item"); rbMenuItem.setSelected(true); rbMenuItem.setMnemonic(KeyEvent.VK_R); group.add(rbMenuItem); rbMenuItem.addActionListener(this); menu.add(rbMenuItem); rbMenuItem = new JRadioButtonMenuItem("Another one"); rbMenuItem.setMnemonic(KeyEvent.VK_O); group.add(rbMenuItem); rbMenuItem.addActionListener(this); menu.add(rbMenuItem); // a group of check box menu items menu.addSeparator(); cbMenuItem = new JCheckBoxMenuItem("A check box menu item"); cbMenuItem.setMnemonic(KeyEvent.VK_C); cbMenuItem.addItemListener(this); menu.add(cbMenuItem); cbMenuItem = new JCheckBoxMenuItem("Another one"); cbMenuItem.setMnemonic(KeyEvent.VK_H); cbMenuItem.addItemListener(this); menu.add(cbMenuItem); // a submenu menu.addSeparator(); submenu = new JMenu("A submenu"); submenu.setMnemonic(KeyEvent.VK_S); menuItem = new JMenuItem("An item in the submenu"); menuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_2, ActionEvent.ALT_MASK)); menuItem.addActionListener(this); submenu.add(menuItem); menuItem = new JMenuItem("Another item"); menuItem.addActionListener(this); submenu.add(menuItem); menu.add(submenu); // Build second menu in the menu bar. menu = new JMenu("Another Menu"); menu.setMnemonic(KeyEvent.VK_N); menu.getAccessibleContext().setAccessibleDescription( "This menu does nothing"); menuBar.add(menu); return menuBar; } public Container createContentPane() { // Create the content-pane-to-be. JPanel contentPane = new JPanel(new BorderLayout()); contentPane.setOpaque(true); // Create a scrolled text area. output = new JTextArea(5, 30); output.setEditable(false); scrollPane = new JScrollPane(output); // Add the text area to the content pane. contentPane.add(scrollPane, BorderLayout.CENTER); return contentPane; } public void createPopupMenu() { JMenuItem menuItem; // Create the popup menu. JPopupMenu popup = new JPopupMenu(); menuItem = new JMenuItem("A popup menu item"); menuItem.addActionListener(this); popup.add(menuItem); menuItem = new JMenuItem("Another popup menu item"); menuItem.addActionListener(this); popup.add(menuItem); // Add listener to the text area so the popup menu can come up. MouseListener popupListener = new PopupListener(popup); output.addMouseListener(popupListener); } public void actionPerformed(ActionEvent e) { JMenuItem source = (JMenuItem) (e.getSource()); String s = "Action event detected." + newline + " Event source: " + source.getText() + " (an instance of " + getClassName(source) + ")"; output.append(s + newline); output.setCaretPosition(output.getDocument().getLength()); } public void itemStateChanged(ItemEvent e) { JMenuItem source = (JMenuItem) (e.getSource()); String s = "Item event detected." + newline + " Event source: " + source.getText() + " (an instance of " + getClassName(source) + ")" + newline + " New state: " + ((e.getStateChange() == ItemEvent.SELECTED) ? "selected" : "unselected"); output.append(s + newline); output.setCaretPosition(output.getDocument().getLength()); } // Returns just the class name -- no package info. protected String getClassName(Object o) { String classString = o.getClass().getName(); int dotIndex = classString.lastIndexOf("."); return classString.substring(dotIndex + 1); } /** Returns an ImageIcon, or null if the path was invalid. */ protected static ImageIcon createImageIcon(String path) { java.net.URL imgURL = DemoJMenu.class.getResource(path); if (imgURL != null) { return new ImageIcon(imgURL); } else { System.err.println("Couldn't find file: " + path); return null; } } /** * Create the GUI and show it. For thread safety, this method should be * invoked from the event-dispatching thread. */ private static void createAndShowGUI() { // Create and set up the window. JFrame frame = new JFrame("DemoRightClickMenu"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // Create/set menu bar and content pane. DemoJMenu demo = new DemoJMenu(); frame.setJMenuBar(demo.createMenuBar()); frame.setContentPane(demo.createContentPane()); // Create and set up the popup menu. demo.createPopupMenu(); // Display the window. frame.setSize(450, 260); frame.setVisible(true); } public static void main(String[] args) { // Schedule a job for the event-dispatching thread: // creating and showing this application's GUI. javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGUI(); } }); } class PopupListener extends MouseAdapter { JPopupMenu popup; PopupListener(JPopupMenu popupMenu) { popup = popupMenu; } public void mousePressed(MouseEvent e) { maybeShowPopup(e); } public void mouseReleased(MouseEvent e) { maybeShowPopup(e); } private void maybeShowPopup(MouseEvent e) { if (e.isPopupTrigger()) { popup.show(e.getComponent(), e.getX(), e.getY()); } } }} |
Đọc thêm: use menu, class jmenu, java swing
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