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 |