We would like to know how to create an text Editor using JTextArea and DefaultEditorKit.
// ww w . ja v a2 s. c om /* Java Swing, 2nd Edition By Marc Loy, Robert Eckstein, Dave Wood, James Elliott, Brian Cole ISBN: 0-596-00408-7 Publisher: O'Reilly */ // Main.java //An example showing several DefaultEditorKit features. This class is designed //to be easily extended for additional functionality. // import java.awt.BorderLayout; import java.awt.Container; import java.awt.event.ActionEvent; import java.io.File; import java.io.FileReader; import java.io.FileWriter; import java.io.IOException; import java.util.Hashtable; import javax.swing.AbstractAction; import javax.swing.Action; import javax.swing.ImageIcon; import javax.swing.JFileChooser; import javax.swing.JFrame; import javax.swing.JMenu; import javax.swing.JMenuBar; import javax.swing.JOptionPane; import javax.swing.JTextArea; import javax.swing.JToolBar; import javax.swing.text.DefaultEditorKit; import javax.swing.text.JTextComponent; public class Main extends JFrame { private Action openAction = new OpenAction(); private Action saveAction = new SaveAction(); private JTextComponent textComp; private Hashtable actionHash = new Hashtable(); public static void main(String[] args) { Main editor = new Main(); editor.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); editor.setVisible(true); } // Create an editor. public Main() { super("Swing Editor"); textComp = createTextComponent(); makeActionsPretty(); Container content = getContentPane(); content.add(textComp, BorderLayout.CENTER); content.add(createToolBar(), BorderLayout.NORTH); setJMenuBar(createMenuBar()); setSize(320, 240); } // Create the JTextComponent subclass. protected JTextComponent createTextComponent() { JTextArea ta = new JTextArea(); ta.setLineWrap(true); return ta; } // Add icons and friendly names to actions we care about. protected void makeActionsPretty() { Action a; a = textComp.getActionMap().get(DefaultEditorKit.cutAction); a.putValue(Action.SMALL_ICON, new ImageIcon("cut.gif")); a.putValue(Action.NAME, "Cut"); a = textComp.getActionMap().get(DefaultEditorKit.copyAction); a.putValue(Action.SMALL_ICON, new ImageIcon("copy.gif")); a.putValue(Action.NAME, "Copy"); a = textComp.getActionMap().get(DefaultEditorKit.pasteAction); a.putValue(Action.SMALL_ICON, new ImageIcon("paste.gif")); a.putValue(Action.NAME, "Paste"); a = textComp.getActionMap().get(DefaultEditorKit.selectAllAction); a.putValue(Action.NAME, "Select All"); } // Create a simple JToolBar with some buttons. protected JToolBar createToolBar() { JToolBar bar = new JToolBar(); // Add simple actions for opening & saving. bar.add(getOpenAction()).setText(""); bar.add(getSaveAction()).setText(""); bar.addSeparator(); // Add cut/copy/paste buttons. bar.add(textComp.getActionMap().get(DefaultEditorKit.cutAction)) .setText(""); bar.add(textComp.getActionMap().get(DefaultEditorKit.copyAction)) .setText(""); bar.add(textComp.getActionMap().get(DefaultEditorKit.pasteAction)) .setText(""); return bar; } // Create a JMenuBar with file & edit menus. protected JMenuBar createMenuBar() { JMenuBar menubar = new JMenuBar(); JMenu file = new JMenu("File"); JMenu edit = new JMenu("Edit"); menubar.add(file); menubar.add(edit); file.add(getOpenAction()); file.add(getSaveAction()); file.add(new ExitAction()); edit.add(textComp.getActionMap().get(DefaultEditorKit.cutAction)); edit.add(textComp.getActionMap().get(DefaultEditorKit.copyAction)); edit.add(textComp.getActionMap().get(DefaultEditorKit.pasteAction)); edit.add(textComp.getActionMap().get(DefaultEditorKit.selectAllAction)); return menubar; } // Subclass can override to use a different open action. protected Action getOpenAction() { return openAction; } // Subclass can override to use a different save action. protected Action getSaveAction() { return saveAction; } protected JTextComponent getTextComponent() { return textComp; } // ********** ACTION INNER CLASSES ********** // // A very simple exit action public class ExitAction extends AbstractAction { public ExitAction() { super("Exit"); } public void actionPerformed(ActionEvent ev) { System.exit(0); } } // An action that opens an existing file class OpenAction extends AbstractAction { public OpenAction() { super("Open", new ImageIcon("icons/open.gif")); } // Query user for a filename and attempt to open and read the file into // the // text component. public void actionPerformed(ActionEvent ev) { JFileChooser chooser = new JFileChooser(); if (chooser.showOpenDialog(Main.this) != JFileChooser.APPROVE_OPTION) return; File file = chooser.getSelectedFile(); if (file == null) return; FileReader reader = null; try { reader = new FileReader(file); textComp.read(reader, null); } catch (IOException ex) { JOptionPane.showMessageDialog(Main.this, "File Not Found", "ERROR", JOptionPane.ERROR_MESSAGE); } finally { if (reader != null) { try { reader.close(); } catch (IOException x) { } } } } } // An action that saves the document to a file class SaveAction extends AbstractAction { public SaveAction() { super("Save", new ImageIcon("icons/save.gif")); } // Query user for a filename and attempt to open and write the text // component's content to the file. public void actionPerformed(ActionEvent ev) { JFileChooser chooser = new JFileChooser(); if (chooser.showSaveDialog(Main.this) != JFileChooser.APPROVE_OPTION) return; File file = chooser.getSelectedFile(); if (file == null) return; FileWriter writer = null; try { writer = new FileWriter(file); textComp.write(writer); } catch (IOException ex) { JOptionPane.showMessageDialog(Main.this, "File Not Saved", "ERROR", JOptionPane.ERROR_MESSAGE); } finally { if (writer != null) { try { writer.close(); } catch (IOException x) { } } } } } }