控制台程序。
在Java中实现对工具提示的支持是非常简单的，秘诀仍在我们一直使用的Action对象中。Action对象拥有存储工具提示文本的内置功能因为文本是通过SHORT_DESCRIPTION键提供的，我们只需要把工具提示文本存储为这个键的值即可。
下面仅列出修改后的SketcherFrame类：
1 // Frame for the Sketcher application 2 import javax.swing.*; 3 import javax.swing.border.*; 4 import java.awt.event.*; 5 import java.awt.*; 6 7 import static java.awt.event.InputEvent.*; 8 import static java.awt.Color.*; 9 import static Constants.SketcherConstants.*; 10 import static javax.swing.Action.*; 11 12 @SuppressWarnings("serial") 13 public class SketcherFrame extends JFrame { 14 // Constructor 15 public SketcherFrame(String title) { 16 setTitle(title); // Set the window title 17 setJMenuBar(menuBar); // Add the menu bar to the window 18 setDefaultCloseOperation(EXIT_ON_CLOSE); // Default is exit the application 19 20 createFileMenu(); // Create the File menu 21 createElementMenu(); // Create the element menu 22 createColorMenu(); // Create the element menu 23 createToolbar(); 24 toolBar.setRollover(true); 25 getContentPane().add(toolBar, BorderLayout.NORTH); 26 } 27 28 // Create File menu item actions 29 private void createFileMenuActions() { 30 newAction = new FileAction("New", 'N', CTRL_DOWN_MASK); 31 openAction = new FileAction("Open", 'O', CTRL_DOWN_MASK); 32 closeAction = new FileAction("Close"); 33 saveAction = new FileAction("Save", 'S', CTRL_DOWN_MASK); 34 saveAsAction = new FileAction("Save As..."); 35 printAction = new FileAction("Print", 'P', CTRL_DOWN_MASK); 36 exitAction = new FileAction("Exit", 'X', CTRL_DOWN_MASK); 37 38 // Initialize the array 39 FileAction[] actions = {openAction, closeAction, saveAction, saveAsAction, printAction, exitAction}; 40 fileActions = actions; 41 // Add toolbar icons 42 newAction.putValue(LARGE_ICON_KEY, NEW24); 43 openAction.putValue(LARGE_ICON_KEY, OPEN24); 44 saveAction.putValue(LARGE_ICON_KEY, SAVE24); 45 saveAsAction.putValue(LARGE_ICON_KEY, SAVEAS24); 46 printAction.putValue(LARGE_ICON_KEY, PRINT24); 47 48 // Add menu item icons 49 newAction.putValue(SMALL_ICON, NEW16); 50 openAction.putValue(SMALL_ICON, OPEN16); 51 saveAction.putValue(SMALL_ICON, SAVE16); 52 saveAsAction.putValue(SMALL_ICON,SAVEAS16); 53 printAction.putValue(SMALL_ICON, PRINT16); 54 55 // Add tooltip text 56 newAction.putValue(SHORT_DESCRIPTION, "Create a new sketch"); 57 openAction.putValue(SHORT_DESCRIPTION, "Read a sketch from a file"); 58 closeAction.putValue(SHORT_DESCRIPTION, "Close the current sketch"); 59 saveAction.putValue(SHORT_DESCRIPTION, "Save the current sketch to file"); 60 saveAsAction.putValue(SHORT_DESCRIPTION, "Save the current sketch to a new file"); 61 printAction.putValue(SHORT_DESCRIPTION, "Print the current sketch"); 62 exitAction.putValue(SHORT_DESCRIPTION, "Exit Sketcher"); 63 } 64 65 // Create the File menu 66 private void createFileMenu() { 67 JMenu fileMenu = new JMenu("File"); // Create File menu 68 fileMenu.setMnemonic('F'); // Create shortcut 69 createFileMenuActions(); // Create Actions for File menu item 70 71 // Construct the file drop-down menu 72 fileMenu.add(newAction); // New Sketch menu item 73 fileMenu.add(openAction); // Open sketch menu item 74 fileMenu.add(closeAction); // Close sketch menu item 75 fileMenu.addSeparator(); // Add separator 76 fileMenu.add(saveAction); // Save sketch to file 77 fileMenu.add(saveAsAction); // Save As menu item 78 fileMenu.addSeparator(); // Add separator 79 fileMenu.add(printAction); // Print sketch menu item 80 fileMenu.addSeparator(); // Add separator 81 fileMenu.add(exitAction); // Print sketch menu item 82 menuBar.add(fileMenu); // Add the file menu 83 } 84 85 // Create Element menu actions 86 private void createElementTypeActions() { 87 lineAction = new TypeAction("Line", LINE, 'L', CTRL_DOWN_MASK); 88 rectangleAction = new TypeAction("Rectangle", RECTANGLE, 'R', CTRL_DOWN_MASK); 89 circleAction = new TypeAction("Circle", CIRCLE,'C', CTRL_DOWN_MASK); 90 curveAction = new TypeAction("Curve", CURVE,'U', CTRL_DOWN_MASK); 91 92 // Initialize the array 93 TypeAction[] actions = {lineAction, rectangleAction, circleAction, curveAction}; 94 typeActions = actions; 95 96 // Add toolbar icons 97 lineAction.putValue(LARGE_ICON_KEY, LINE24); 98 rectangleAction.putValue(LARGE_ICON_KEY, RECTANGLE24); 99 circleAction.putValue(LARGE_ICON_KEY, CIRCLE24); 100 curveAction.putValue(LARGE_ICON_KEY, CURVE24); 101 102 // Add menu item icons 103 lineAction.putValue(SMALL_ICON, LINE16); 104 rectangleAction.putValue(SMALL_ICON, RECTANGLE16); 105 circleAction.putValue(SMALL_ICON, CIRCLE16); 106 curveAction.putValue(SMALL_ICON, CURVE16); 107 108 // Add tooltip text 109 lineAction.putValue(SHORT_DESCRIPTION, "Draw lines"); 110 rectangleAction.putValue(SHORT_DESCRIPTION, "Draw rectangles"); 111 circleAction.putValue(SHORT_DESCRIPTION, "Draw circles"); 112 curveAction.putValue(SHORT_DESCRIPTION, "Draw curves"); 113 } 114 115 // Create the Elements menu 116 private void createElementMenu() { 117 createElementTypeActions(); 118 elementMenu = new JMenu("Elements"); // Create Elements menu 119 elementMenu.setMnemonic('E'); // Create shortcut 120 createRadioButtonDropDown(elementMenu, typeActions, lineAction); 121 menuBar.add(elementMenu); // Add the element menu 122 } 123 124 // Create Color menu actions 125 private void createElementColorActions() { 126 redAction = new ColorAction("Red", RED, 'R', CTRL_DOWN_MASK|ALT_DOWN_MASK); 127 yellowAction = new ColorAction("Yellow", YELLOW, 'Y', CTRL_DOWN_MASK|ALT_DOWN_MASK); 128 greenAction = new ColorAction("Green", GREEN, 'G', CTRL_DOWN_MASK|ALT_DOWN_MASK); 129 blueAction = new ColorAction("Blue", BLUE, 'B', CTRL_DOWN_MASK|ALT_DOWN_MASK); 130 131 // Initialize the array 132 ColorAction[] actions = {redAction, greenAction, blueAction, yellowAction}; 133 colorActions = actions; 134 135 // Add toolbar icons 136 redAction.putValue(LARGE_ICON_KEY, RED24); 137 greenAction.putValue(LARGE_ICON_KEY, GREEN24); 138 blueAction.putValue(LARGE_ICON_KEY, BLUE24); 139 yellowAction.putValue(LARGE_ICON_KEY, YELLOW24); 140 141 // Add menu item icons 142 redAction.putValue(SMALL_ICON, RED16); 143 greenAction.putValue(SMALL_ICON, GREEN16); 144 blueAction.putValue(SMALL_ICON, BLUE16); 145 yellowAction.putValue(SMALL_ICON, YELLOW16); 146 147 // Add tooltip text 148 redAction.putValue(SHORT_DESCRIPTION, "Draw in red"); 149 blueAction.putValue(SHORT_DESCRIPTION, "Draw in blue"); 150 greenAction.putValue(SHORT_DESCRIPTION, "Draw in green"); 151 yellowAction.putValue(SHORT_DESCRIPTION, "Draw in yellow"); 152 } 153 154 // Create the Color menu 155 private void createColorMenu() { 156 createElementColorActions(); 157 colorMenu = new JMenu("Color"); // Create Elements menu 158 colorMenu.setMnemonic('C'); // Create shortcut 159 createRadioButtonDropDown(colorMenu, colorActions, blueAction); 160 menuBar.add(colorMenu); // Add the color menu 161 } 162 163 // Menu creation helper 164 private void createRadioButtonDropDown(JMenu menu, Action[] actions, Action selected) { 165 ButtonGroup group = new ButtonGroup(); 166 JRadioButtonMenuItem item = null; 167 for(Action action : actions) { 168 group.add(menu.add(item = new JRadioButtonMenuItem(action))); 169 if(action == selected) { 170 item.setSelected(true); // This is default selected 171 } 172 } 173 } 174 175 // Create toolbar buttons on the toolbar 176 private void createToolbar() { 177 for(FileAction action: fileActions){ 178 if(action != exitAction && action != closeAction) 179 addToolbarButton(action); // Add the toolbar button 180 } 181 toolBar.addSeparator(); 182 183 // Create Color menu buttons 184 for(ColorAction action:colorActions){ 185 addToolbarButton(action); // Add the toolbar button 186 } 187 188 toolBar.addSeparator(); 189 190 // Create Elements menu buttons 191 for(TypeAction action:typeActions){ 192 addToolbarButton(action); // Add the toolbar button 193 } 194 } 195 196 // Create and add a toolbar button 197 private void addToolbarButton(Action action) { 198 JButton button = new JButton(action); // Create from Action 199 button.setBorder(BorderFactory.createCompoundBorder( // Add button border 200 new EmptyBorder(2,5,5,2), // Outside border 201 BorderFactory.createRaisedBevelBorder())); // Inside border 202 button.setHideActionText(true); // No label on the button 203 toolBar.add(button); // Add the toolbar button 204 } 205 206 // Set radio button menu checks 207 private void setChecks(JMenu menu, Object eventSource) { 208 if(eventSource instanceof JButton){ 209 JButton button = (JButton)eventSource; 210 Action action = button.getAction(); 211 for(int i = 0 ; i < menu.getItemCount() ; ++i) { 212 JMenuItem item = menu.getItem(i); 213 item.setSelected(item.getAction() == action); 214 } 215 } 216 } 217 218 // Inner class defining Action objects for File menu items 219 class FileAction extends AbstractAction { 220 // Create action with a name 221 FileAction(String name) { 222 super(name); 223 } 224 225 // Create action with a name and accelerator 226 FileAction(String name, char ch, int modifiers) { 227 super(name); 228 putValue(ACCELERATOR_KEY, KeyStroke.getKeyStroke(ch, modifiers)); 229 230 // Now find the character to underline 231 int index = name.toUpperCase().indexOf(ch); 232 if(index != -1) { 233 putValue(DISPLAYED_MNEMONIC_INDEX_KEY, index); 234 } 235 } 236 237 // Event handler 238 public void actionPerformed(ActionEvent e) { 239 // You will add action code here eventually... 240 } 241 } 242 243 // Inner class defining Action objects for Element type menu items 244 class TypeAction extends AbstractAction { 245 // Create action with just a name property 246 TypeAction(String name, int typeID) { 247 super(name); 248 this.typeID = typeID; 249 } 250 251 // Create action with a name and an accelerator 252 private TypeAction(String name,int typeID, char ch, int modifiers) { 253 this(name, typeID); 254 putValue(ACCELERATOR_KEY, KeyStroke.getKeyStroke(ch, modifiers)); 255 256 // Now find the character to underline 257 int index = name.toUpperCase().indexOf(ch); 258 if(index != -1) { 259 putValue(DISPLAYED_MNEMONIC_INDEX_KEY, index); 260 } 261 } 262 263 public void actionPerformed(ActionEvent e) { 264 elementType = typeID; 265 setChecks(elementMenu, e.getSource()); 266 } 267 268 private int typeID; 269 } 270 271 // Handles color menu items 272 class ColorAction extends AbstractAction { 273 // Create an action with a name and a color 274 public ColorAction(String name, Color color) { 275 super(name); 276 this.color = color; 277 } 278 279 // Create an action with a name, a color, and an accelerator 280 public ColorAction(String name, Color color, char ch, int modifiers) { 281 this(name, color); 282 putValue(ACCELERATOR_KEY, KeyStroke.getKeyStroke(ch, modifiers)); 283 284 // Now find the character to underline 285 int index = name.toUpperCase().indexOf(ch); 286 if(index != -1) { 287 putValue(DISPLAYED_MNEMONIC_INDEX_KEY, index); 288 } 289 } 290 291 public void actionPerformed(ActionEvent e) { 292 elementColor = color; 293 setChecks(colorMenu, e.getSource()); 294 } 295 296 private Color color; 297 } 298 299 // File actions 300 private FileAction newAction, openAction, closeAction, saveAction, saveAsAction, printAction, exitAction; 301 private FileAction[] fileActions; // File actions as an array 302 303 // Element type actions 304 private TypeAction lineAction, rectangleAction, circleAction, curveAction; 305 private TypeAction[] typeActions; // Type actions as an array 306 307 // Element color actions 308 private ColorAction redAction, yellowAction,greenAction, blueAction; 309 private ColorAction[] colorActions; // Color actions as an array 310 311 private JMenuBar menuBar = new JMenuBar(); // Window menu bar 312 private JMenu elementMenu; // Elements menu 313 private JMenu colorMenu; // Color menu 314 315 private Color elementColor = DEFAULT_ELEMENT_COLOR; // Current element color 316 private int elementType = DEFAULT_ELEMENT_TYPE; // Current element type 317 private JToolBar toolBar = new JToolBar(); // Window toolbar 318 }