/** Creates the EditorLite object and displays the GUI with an empty editor pane. */
public EditorLite() {
/* Scrollable Text Panes */
// create some text areas
// these are dimensionless to let the layout handle it
editor = new JTextArea();
editor.setLineWrap(true);
editor.setWrapStyleWord(true);
editor.addKeyListener(this);
side = new JTextArea();
side.setLineWrap(true);
side.setEditable(false);
// create the scroll panes (to house the text areas)
editorPane = new JScrollPane(editor);
sidePane = new JScrollPane(side);
centerPanel = new JPanel(new GridLayout(1, 2));
centerPanel.add(editorPane);
centerPanel.add(sidePane);
/* Button Panel */
// create the buttonPanel
buttonPanel = new JPanel(new FlowLayout());
// create the buttons
fileChooserButton = new JButton("Open File");
sideButton = new JButton("Copy to Side Pane");
// add action listeners to the buttons
fileChooserButton.addActionListener(this);
sideButton.addActionListener(this);
// add the buttons to the buttonPanel
buttonPanel.add(fileChooserButton);
buttonPanel.add(sideButton);
/* Menu Bar */
// create a menu bar
menuBar = new JMenuBar();
// create menus to add to the menu bar
// also setup mnemonics for keyboard access
fileMenu = new JMenu("File");
editMenu = new JMenu("Edit");
formatMenu = new JMenu("Format");
viewMenu = new JMenu("View");
helpMenu = new JMenu("Help");
fileMenu.setMnemonic(KeyEvent.VK_F);
editMenu.setMnemonic(KeyEvent.VK_E);
formatMenu.setMnemonic(KeyEvent.VK_O);
viewMenu.setMnemonic(KeyEvent.VK_V);
helpMenu.setMnemonic(KeyEvent.VK_H);
fileMenu.setDisplayedMnemonicIndex(0);
editMenu.setDisplayedMnemonicIndex(0);
formatMenu.setDisplayedMnemonicIndex(1);
viewMenu.setDisplayedMnemonicIndex(0);
helpMenu.setDisplayedMnemonicIndex(0);
// create menu items to add to the menus
// also setup mnemonics for keyboard access
// note: \u2026 is a unicode ellipsis (ie, '...')
newFile = new JMenuItem("New", KeyEvent.VK_N);
open = new JMenuItem("Open\u2026", KeyEvent.VK_O);
save = new JMenuItem("Save", KeyEvent.VK_S);
saveAs = new JMenuItem("Save As\u2026", KeyEvent.VK_A);
close = new JMenuItem("Exit", KeyEvent.VK_X);
newFile.setDisplayedMnemonicIndex(0);
open.setDisplayedMnemonicIndex(0);
save.setDisplayedMnemonicIndex(0);
saveAs.setDisplayedMnemonicIndex(5);
close.setDisplayedMnemonicIndex(1);
newFile.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_N, ActionEvent.CTRL_MASK));
open.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_O, ActionEvent.CTRL_MASK));
save.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_S, ActionEvent.CTRL_MASK));
// disable the save JMenuItem by default
save.setEnabled(false);
cut = new JMenuItem("Cut", KeyEvent.VK_T);
copy = new JMenuItem("Copy", KeyEvent.VK_C);
paste = new JMenuItem("Paste", KeyEvent.VK_P);
deleteSelected = new JMenuItem("Delete", KeyEvent.VK_L);
cut.setDisplayedMnemonicIndex(2);
copy.setDisplayedMnemonicIndex(0);
paste.setDisplayedMnemonicIndex(0);
deleteSelected.setDisplayedMnemonicIndex(2);
cut.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_X, ActionEvent.CTRL_MASK));
copy.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_C, ActionEvent.CTRL_MASK));
paste.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_V, ActionEvent.CTRL_MASK));
deleteSelected.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_DELETE, 0));
wordWrap = new JCheckBoxMenuItem("Word Wrap", true);
wordWrap.setMnemonic(KeyEvent.VK_W);
wordWrap.setDisplayedMnemonicIndex(7);
toggleSide = new JCheckBoxMenuItem("Side Pane", true);
toggleSide.setMnemonic(KeyEvent.VK_S);
toggleSide.setDisplayedMnemonicIndex(7);
about = new JMenuItem("About " + programName, KeyEvent.VK_A);
about.setDisplayedMnemonicIndex(0);
// add action listeners to the menu items
newFile.addActionListener(this);
open.addActionListener(this);
save.addActionListener(this);
saveAs.addActionListener(this);
close.addActionListener(this);
cut.addActionListener(this);
copy.addActionListener(this);
paste.addActionListener(this);
deleteSelected.addActionListener(this);
wordWrap.addItemListener(this);
toggleSide.addItemListener(this);
about.addActionListener(this);
// add the menu items to the menus
fileMenu.add(newFile);
fileMenu.add(open);
fileMenu.add(save);
fileMenu.add(saveAs);
fileMenu.add(close);
editMenu.add(cut);
editMenu.add(copy);
editMenu.add(paste);
editMenu.add(deleteSelected);
formatMenu.add(wordWrap);
viewMenu.add(toggleSide);
helpMenu.add(about);
// add the menus to the menu bar
menuBar.add(fileMenu);
menuBar.add(editMenu);
menuBar.add(formatMenu);
menuBar.add(viewMenu);
menuBar.add(helpMenu);
/* Main Frame */
// initialize
mainFrame = new JFrame("EditorLite");
// add the listener for windowClosing event
mainFrame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
mainFrame.addWindowListener(
new WindowAdapter() {
public void windowClosing(WindowEvent winEvt) {
if (isUnsavedFile()) {
int choice = displayUnsavedWarning();
if (choice == JOptionPane.YES_OPTION) {
System.exit(0);
}
} else {
System.exit(0);
}
}
});
// set up the layout
mainFrame.setJMenuBar(menuBar);
mainFrame.add(centerPanel, BorderLayout.CENTER);
mainFrame.add(buttonPanel, BorderLayout.SOUTH);
// pack and set a reasonable start size
mainFrame.pack();
mainFrame.setSize(600, 400);
// center the window on the screen
// basically, it gets the width of the screen, subtracts the width of the frame,
// and then divides by 2 for the x coordinate
int xCoord =
(Toolkit.getDefaultToolkit().getScreenSize().width - mainFrame.getSize().width) / 2;
// similarly, it gets the height of the screen, subtracts the height of the frame,
// and then divides by 2 for the y coordinate
int yCoord =
(Toolkit.getDefaultToolkit().getScreenSize().height - mainFrame.getSize().height) / 2;
mainFrame.setLocation(xCoord, yCoord);
// finally, make it visible
mainFrame.setVisible(true);
}
