sketchframe.java

JAVA 2入门经典 练习答案

// Frame for the Sketcher application
import javax.swing.JMenuBar;
import javax.swing.KeyStroke;
import javax.swing.JMenuItem;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JToolBar;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
import javax.swing.JLabel;
import javax.swing.JDialog;
import javax.swing.JOptionPane;
import javax.swing.JPopupMenu;
import javax.swing.JColorChooser;

import java.awt.Color;
import java.awt.Event;
import java.awt.BorderLayout;
import java.awt.Point;
import java.awt.Dimension;
import java.awt.Frame;
import java.awt.Font;
import java.awt.Rectangle;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import java.io.File;

public class SketchFrame extends JFrame implements Constants, ActionListener {

  // Constructor
  public SketchFrame(String title, Sketcher theApp) {
    setTitle(title);                             // Set the window title
    this.theApp = theApp;
    setJMenuBar(menuBar);                       // Add the menu bar to the window
    setDefaultCloseOperation(EXIT_ON_CLOSE);      // Default is exit the application

    JMenu fileMenu = new JMenu("File");          // Create File menu
    JMenu elementMenu = new JMenu("Elements");   // Create Elements menu
    JMenu optionsMenu = new JMenu("Options");              // Create options menu
    JMenu helpMenu = new JMenu("Help");           // Create Help menu

    fileMenu.setMnemonic('F');                   // Create shortcut
    elementMenu.setMnemonic('E');                // Create shortcut
    optionsMenu.setMnemonic('O');                          // Create shortcut
    helpMenu.setMnemonic('H');                    // Create shortcut 

    // Create the action items for the file menu
    newAction = new FileAction("New", KeyStroke.getKeyStroke('N',Event.CTRL_MASK ), "Create new sketch");
    openAction = new FileAction("Open", KeyStroke.getKeyStroke('O',Event.CTRL_MASK), "Open existing sketch");
    closeAction = new FileAction("Close", "Close sketch");
    saveAction = new FileAction("Save", KeyStroke.getKeyStroke('S',Event.CTRL_MASK), "Save sketch");
    saveAsAction = new FileAction("Save As...", "Save as new file");
    printAction = new FileAction("Print", KeyStroke.getKeyStroke('P',Event.CTRL_MASK), "Print sketch");

    addMenuItem(fileMenu, newAction);
    addMenuItem(fileMenu, openAction);
    addMenuItem(fileMenu, closeAction);
    fileMenu.addSeparator();                                      // Add separator
    addMenuItem(fileMenu, saveAction);
    addMenuItem(fileMenu, saveAsAction);
    fileMenu.addSeparator();                                      // Add separator
    addMenuItem(fileMenu, printAction);

    // Construct the Element pull down menu
    addMenuItem(elementMenu, lineAction = new TypeAction("Line", LINE, "Draw lines")); 
    addMenuItem(elementMenu, rectangleAction = new TypeAction("Rectangle",RECTANGLE, "Draw rectangles"));
    addMenuItem(elementMenu, circleAction = new TypeAction("Circle", CIRCLE, "Draw circles"));
    addMenuItem(elementMenu, curveAction = new TypeAction("Curve", CURVE, "Draw curves"));
    addMenuItem(elementMenu, textAction = new TypeAction("Text", TEXT, "Draw text"));

    elementMenu.addSeparator();                      // Add separator

    JMenu colorMenu = new JMenu("Color");         // Color sub-menu
    elementMenu.add(colorMenu);                   // Add the sub-menu

    addMenuItem(colorMenu, redAction = new ColorAction("Red", Color.RED, "Draw in red"));
    addMenuItem(colorMenu, yellowAction = new ColorAction("Yellow", Color.YELLOW, "Draw in yellow"));
    addMenuItem(colorMenu, greenAction = new ColorAction("Green", Color.GREEN, "Draw in green"));
    addMenuItem(colorMenu, blueAction = new ColorAction("Blue", Color.BLUE, "Draw in blue"));
    
    menuBar.add(fileMenu);                       // Add the file menu
    menuBar.add(elementMenu);                    // Add the element menu 
    menuBar.add(optionsMenu);                     // Add the options menu
    
    toolBar.setFloatable(false);    // Inhibit toolbar floating
    getContentPane().add(toolBar, BorderLayout.NORTH);

    // Add file buttons
    toolBar.addSeparator();                                 // Space at the start
    addToolBarButton(newAction);
    addToolBarButton(openAction);
    addToolBarButton(saveAction);
    addToolBarButton(printAction);
    
    // Add element type buttons
    toolBar.addSeparator();
    addToolBarButton(lineAction);
    addToolBarButton(rectangleAction);
    addToolBarButton(circleAction);
    addToolBarButton(curveAction);
    addToolBarButton(textAction);

    // Add element color buttons
    toolBar.addSeparator();
    addToolBarButton(redAction);
    addToolBarButton(yellowAction);
    addToolBarButton(greenAction);
    addToolBarButton(blueAction);
    addToolBarButton(new ColorDialogAction());
    toolBar.addSeparator();                            // Space at the end

    toolBar.setBorder(BorderFactory.createCompoundBorder(       // Toolbar border
                      BorderFactory.createLineBorder(Color.darkGray),
                      BorderFactory.createEmptyBorder(2,2,4,2)));   

    toolBar.setFloatable(false);                       // Inhibit toolbar floating
    getContentPane().add(toolBar, BorderLayout.NORTH); // Add the toolbar
    
    // Disable actions
    saveAction.setEnabled(false);
    closeAction.setEnabled(false);
    printAction.setEnabled(false);

    getContentPane().add(statusBar, BorderLayout.SOUTH);        // Add the statusbar

    // Add the About item to the Help menu
    aboutItem = new JMenuItem("About");           // Create the item
    aboutItem.addActionListener(this);            // Listener is the frame
    helpMenu.add(aboutItem);                      // Add item to menu
    menuBar.add(helpMenu);                        // Add the Help menu

    // Add the font choice item to the options menu
    fontItem = new JMenuItem("Choose font...");
    fontItem.addActionListener(this);
    optionsMenu.add(fontItem);

    fontDlg = new FontDialog(this);
    
    // Create pop-up menu
    popup.add(lineAction);
    popup.add(rectangleAction);
    popup.add(circleAction);
    popup.add(curveAction);
    popup.add(textAction);

    popup.addSeparator();
    popup.add(redAction);
    popup.add(yellowAction);
    popup.add(greenAction);
    popup.add(blueAction);

    customColorItem = popup.add("Custom Color...");    // Add the item
    customColorItem.addActionListener(this);           // and add its listener
  }

  // Retrieve the pop-up menu
  public JPopupMenu getPopup() {  
    return popup;  
  }

  private JButton addToolBarButton(Action action) {
    JButton button = toolBar.add(action);              // Add toolbar button
    button.setBorder(BorderFactory.createRaisedBevelBorder());// Add button border
    return button;
  }

  // Defines an Action object for the toolbar button to display a color
  // selection dialog
  class ColorDialogAction extends AbstractAction {
    // Constructor
    public ColorDialogAction() {
      String iconFileName = "Images/ColorDialog.gif";
      if(new File(iconFileName).exists())
        putValue(SMALL_ICON, new ImageIcon(iconFileName));
      putValue(SHORT_DESCRIPTION, "Select color...");
    }

    // When the button is clicked, this method displays an option dialog
    // for choosing a color. If the Custom... option is selected a
    // JColorChooser dialog is display for choosing a custom color.
    public void actionPerformed(ActionEvent e) {
      Rectangle bounds = getBounds();

      int choice = choices.length-1;
      for(int i = 0 ; i<colors.length ; i++)
        if(elementColor.equals(colors[i])){
          choice = i;
          break;
        }
      String input = (String)JOptionPane.showInputDialog(null, "Pick a color...",
                                  "Element Color Choice", JOptionPane.PLAIN_MESSAGE,
                                     null, choices, choices[choice]);
      if(input.equals(choices[choices.length-1])) {
              Color color = JColorChooser.showDialog(null, "Select Custom Color",
                                                               elementColor);
              if(color != null) 
                elementColor = color;
      } else {
    
        for(int i = 0 ; i<choices.length-1 ; i++)
          if(input.equals(choices[i])) {
            elementColor = colors[i];
            break;
          }