This simple text editor uses a JTextArea with Actions to
implement the menu items. Actions are a good way to implement ActionListeners.
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// editor/NutPad.java -- A very simple text editor -- Fred Swartz - 2004-08
// Illustrates use of AbstractActions for menus.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
public class NutPad extends JFrame {
//-- Components
private JTextArea mEditArea;
private JFileChooser mFileChooser = new JFileChooser(".");
//-- Actions
private Action mOpenAction;
private Action mSaveAction;
private Action mExitAction;
//===================================================================== main
public static void main(String[] args) {
new NutPad().setVisible(true);
}//end main
//============================================================== constructor
public NutPad() {
createActions();
this.setContentPane(new contentPanel());
this.setJMenuBar(createMenuBar());
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setTitle("NutPad");
this.pack();
}//end constructor
///////////////////////////////////////////////////////// class contentPanel
private class contentPanel extends JPanel {
//========================================================== constructor
contentPanel() {
//-- Create components.
mEditArea = new JTextArea(15, 80);
mEditArea.setBorder(BorderFactory.createEmptyBorder(2,2,2,2));
mEditArea.setFont(new Font("monospaced", Font.PLAIN, 14));
JScrollPane scrollingText = new JScrollPane(mEditArea);
//-- Do layout
this.setLayout(new BorderLayout());
this.add(scrollingText, BorderLayout.CENTER);
}//end constructor
}//end class contentPanel
//============================================================ createMenuBar
/** Utility function to create a menubar. */
private JMenuBar createMenuBar() {
JMenuBar menuBar = new JMenuBar();
JMenu fileMenu = menuBar.add(new JMenu("File"));
fileMenu.add(mOpenAction); // Note use of actions, not text.
fileMenu.add(mSaveAction);
fileMenu.addSeparator();
fileMenu.add(mExitAction);
return menuBar;
}//end createMenuBar
//============================================================ createActions
/** Utility function to define actions. */
private void createActions() {
mOpenAction = new AbstractAction("Open...") {
public void actionPerformed(ActionEvent e) {
int retval = mFileChooser.showOpenDialog(NutPad.this);
if (retval == JFileChooser.APPROVE_OPTION) {
File f = mFileChooser.getSelectedFile();
try {
FileReader reader = new FileReader(f);
mEditArea.read(reader, ""); // Use TextComponent read
} catch (IOException ioex) {
System.out.println(e);
System.exit(1);
}
}
}
};
mSaveAction = new AbstractAction("Save") {
public void actionPerformed(ActionEvent e) {
int retval = mFileChooser.showSaveDialog(NutPad.this);
if (retval == JFileChooser.APPROVE_OPTION) {
File f = mFileChooser.getSelectedFile();
try {
FileWriter writer = new FileWriter(f);
mEditArea.write(writer); // Use TextComponent write
} catch (IOException ioex) {
System.out.println(e);
System.exit(1);
}
}
}
};
mExitAction = new AbstractAction("Exit") {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
};
}//end createActions
}//end class NutPad
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