How to use Ctrl+Z and Ctrl+Y with all Text Components?

Question

In fact i know how to implement using CTRL+Z (Undo) and CTRL+Y (Redo) with one JTextField. But i have hundreds of Text Components in my Swing application, so is there a way to apply this for all Text Components in my application, so when i click CTRL+Z in any Text Component it would undo the last entry in that Field ?

I have tried to implement it in EventQueue, but it did not work !

Answer 1

To make all your text components "undoable", you can simply create them using your own subclass like:

public class MyTextField extends JTextField {
    public MyTextField() {
        final UndoManager undoMgr = new UndoManager();

        // Add listener for undoable events
        getDocument().addUndoableEditListener(new UndoableEditListener() {
            public void undoableEditHappened(UndoableEditEvent pEvt) {
                undoMgr.addEdit(pEvt.getEdit());
            }
        });

        // Add undo/redo actions
        getActionMap().put(UNDO_ACTION, new AbstractAction(UNDO_ACTION) {
            public void actionPerformed(ActionEvent pEvt) {
                try {
                    if (undoMgr.canUndo()) {
                        undoMgr.undo();
                    }
                } catch (CannotUndoException e) {
                    e.printStackTrace();
                }
            }
        });
        getActionMap().put(REDO_ACTION, new AbstractAction(REDO_ACTION) {
            public void actionPerformed(ActionEvent pEvt) {
                try {
                    if (undoMgr.canRedo()) {
                        undoMgr.redo();
                    }
                } catch (CannotRedoException e) {
                    e.printStackTrace();
                }
            }
        });

        // Create keyboard accelerators for undo/redo actions (Ctrl+Z/Ctrl+Y)
        getInputMap().put(KeyStroke.getKeyStroke(KeyEvent.VK_Z, InputEvent.CTRL_DOWN_MASK),
            UNDO_ACTION);
        getInputMap().put(KeyStroke.getKeyStroke(KeyEvent.VK_Y, InputEvent.CTRL_DOWN_MASK),
            REDO_ACTION);
    }
}

Then instead of creating JTextFields, create MyTextFields. The limitation is that you may also want to create another subclass for JTextArea and so on for other JTextComponents. So it is also possible to use an utility method to add Undo/Redo features to any existing JTextCompoent:

public final static String UNDO_ACTION = "Undo";

public final static String REDO_ACTION = "Redo";

public static void makeUndoable(JTextComponent pTextComponent) {
    final UndoManager undoMgr = new UndoManager();

    // Add listener for undoable events
    pTextComponent.getDocument().addUndoableEditListener(new UndoableEditListener() {
        public void undoableEditHappened(UndoableEditEvent evt) {
            undoMgr.addEdit(evt.getEdit());
        }
    });

    // Add undo/redo actions
    pTextComponent.getActionMap().put(UNDO_ACTION, new AbstractAction(UNDO_ACTION) {
        public void actionPerformed(ActionEvent evt) {
            try {
                if (undoMgr.canUndo()) {
                    undoMgr.undo();
                }
            } catch (CannotUndoException e) {
                e.printStackTrace();
            }
        }
    });
    pTextComponent.getActionMap().put(REDO_ACTION, new AbstractAction(REDO_ACTION) {
        public void actionPerformed(ActionEvent evt) {
            try {
                if (undoMgr.canRedo()) {
                    undoMgr.redo();
                }
            } catch (CannotRedoException e) {
                e.printStackTrace();
            }
        }
    });

    // Create keyboard accelerators for undo/redo actions (Ctrl+Z/Ctrl+Y)
    pTextComponent.getInputMap().put(
        KeyStroke.getKeyStroke(KeyEvent.VK_Z, InputEvent.CTRL_DOWN_MASK), UNDO_ACTION);
    pTextComponent.getInputMap().put(
        KeyStroke.getKeyStroke(KeyEvent.VK_Y, InputEvent.CTRL_DOWN_MASK), REDO_ACTION);
}

The final and absolutely transparent solution would be to implement your own UI class using Lnf features, but you may want to think twice before making all TextComponents undoable, for memory consumptions reasons for example if you often perform huge text modifications to these components...

Answer 2

• you can gel list of built_in KeyBindings short_cuts implemented in the API's

• notice you have to check or prepare your code for all accesible Look and Feels

• you can get built_in KeyBindings short_cuts and replace that as you expecting, System ClipBoard is very often modified,

• never tried but on this forum you can foud out rellevant info How to change, replace KeyBindings short_cuts

list of built_in KeyBindings short_cuts

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.table.*;
import javax.swing.filechooser.*;

public class KeyBindings implements ItemListener {

    private static final String PACKAGE = "javax.swing.";
    private static final String[] COLUMN_NAMES = {"Action", "When Focused", "When In Focused Window", "When Ancestor"};
    private static String selectedItem;
    private JComponent contentPane;
    private JMenuBar menuBar;
    private JTable table;
    private JComboBox comboBox;
    private Hashtable<String, DefaultTableModel> models;

    /*
     *  Constructor
     */
    public KeyBindings() {
        models = new Hashtable<String, DefaultTableModel>();
        contentPane = new JPanel(new BorderLayout());
        contentPane.add(buildNorthComponent(), BorderLayout.NORTH);
        contentPane.add(buildCenterComponent(), BorderLayout.CENTER);
        resetComponents();
    }

    /*
     *  The content pane should be added to a high level container
     */
    public JComponent getContentPane() {
        return contentPane;
    }

    /*
     *  A menu can also be added which provides the ability to switch
     *  between different LAF's.
     */
    public JMenuBar getMenuBar() {
        if (menuBar == null) {
            menuBar = createMenuBar();
        }
        return menuBar;
    }

    /*
     *  This panel is added to the North of the content pane
     */
    private JComponent buildNorthComponent() {
        comboBox = new JComboBox();
        JLabel label = new JLabel("Select Component:");
        label.setDisplayedMnemonic('S');
        label.setLabelFor(comboBox);
        JPanel panel = new JPanel();
        panel.setBorder(new EmptyBorder(15, 0, 15, 0));
        panel.add(label);
        panel.add(comboBox);
        return panel;
    }

    /*
     *  Check the key name to see if it is the UI property
     */
    private String checkForUIKey(String key) {
        if (key.endsWith("UI") && key.indexOf('.') == -1) {
            String componentName = key.substring(0, key.length() - 2);//  Ignore these components
            if (componentName.equals("PopupMenuSeparator") || componentName.equals("ToolBarSeparator") || componentName.equals("DesktopIcon")) {
                return null;
            } else {
                return componentName;
            }
        }
        return null;
    }

    /*
     **  Build the emtpy table to be added in the Center
     */
    private JComponent buildCenterComponent() {
        DefaultTableModel model = new DefaultTableModel(COLUMN_NAMES, 0);
        table = new JTable(model) {

            private static final long serialVersionUID = 1L;

            @Override
            public boolean isCellEditable(int row, int column) {
                return false;
            }
        };
        table.setAutoCreateColumnsFromModel(false);
        table.getColumnModel().getColumn(0).setPreferredWidth(200);
        table.getColumnModel().getColumn(1).setPreferredWidth(200);
        table.getColumnModel().getColumn(2).setPreferredWidth(200);
        table.getColumnModel().getColumn(3).setPreferredWidth(200);
        Dimension d = table.getPreferredSize();
        d.height = 350;
        table.setPreferredScrollableViewportSize(d);
        table.getTableHeader().setFocusable(true);
        return new JScrollPane(table);
    }

    /*
     *  When the LAF is changed we need to reset all the items
     */
    private void resetComponents() {
        models.clear();
        ((DefaultTableModel) table.getModel()).setRowCount(0);
        Vector<String> comboBoxItems = new Vector<String>(50);//        buildItemsMap();
        UIDefaults defaults = UIManager.getLookAndFeelDefaults();
        for (Object key : defaults.keySet()) { //  All Swing components will have a UI property.
            String componentName = checkForUIKey(key.toString());
            if (componentName != null) {
                comboBoxItems.add(componentName);
            }
        }
        Collections.sort(comboBoxItems);
        comboBox.removeItemListener(this);
        comboBox.setModel(new DefaultComboBoxModel(comboBoxItems));
        comboBox.setSelectedIndex(-1);
        comboBox.addItemListener(this);
        comboBox.requestFocusInWindow();
        if (selectedItem != null) {
            comboBox.setSelectedItem(selectedItem);
        }
    }

    /**
     *  Create menu bar
     */
    private JMenuBar createMenuBar() {
        JMenuBar menuBar1 = new JMenuBar();
        menuBar1.add(createFileMenu());
        menuBar1.add(createLAFMenu());
        return menuBar1;
    }

    /**
     *  Create menu items for the Application menu
     */
    private JMenu createFileMenu() {
        JMenu menu = new JMenu("Application");
        menu.setMnemonic('A');
        menu.addSeparator();
        menu.add(new ExitAction());
        return menu;
    }

    /**
     *  Create menu items for the Look & Feel menu
     */
    private JMenu createLAFMenu() {
        ButtonGroup bg = new ButtonGroup();
        JMenu menu = new JMenu("Look & Feel");
        menu.setMnemonic('L');
        String lafId = UIManager.getLookAndFeel().getID();
        UIManager.LookAndFeelInfo[] lafInfo = UIManager.getInstalledLookAndFeels();
        for (int i = 0; i < lafInfo.length; i++) {
            String laf = lafInfo[i].getClassName();
            String name = lafInfo[i].getName();
            Action action = new ChangeLookAndFeelAction(laf, name);
            JRadioButtonMenuItem mi = new JRadioButtonMenuItem(action);
            menu.add(mi);
            bg.add(mi);
            if (name.equals(lafId)) {
                mi.setSelected(true);
            }
        }
        return menu;
    }

    /*
     *  Implement the ItemListener interface
     */
    @Override
    public void itemStateChanged(ItemEvent e) {
        String componentName = (String) e.getItem();
        changeTableModel(getClassName(componentName));
        selectedItem = componentName;
    }

    /*
     *  Use the component name to build the class name
     */
    private String getClassName(String componentName) {
        if (componentName.equals("TableHeader")) {//  The table header is in a child package
            return PACKAGE + "table.JTableHeader";
        } else {
            return PACKAGE + "J" + componentName;
        }
    }

    /*
     *  Change the TabelModel in the table for the selected component
     */
    private void changeTableModel(String className) {
        DefaultTableModel model = models.get(className); //  Check if we have already built the table model for this component
        if (model != null) {
            table.setModel(model);
            return;
        }
        model = new DefaultTableModel(COLUMN_NAMES, 0); //  Create an empty table to start with
        table.setModel(model);
        models.put(className, model);
        JComponent component = null; //  Create an instance of the component so we can get the default Action map and Input maps
        try {
            if (className.endsWith("JFileChooser")) {//  Hack so I don't have to sign the jar file for usage in  Java Webstart
                component = new JFileChooser(new DummyFileSystemView());
            } else {
                Object o = Class.forName(className).newInstance();
                component = (JComponent) o;
            }
        } catch (Exception e) {
            Object[] row = {e.toString(), "", "", ""};
            model.addRow(row);
            return;
        }
        ActionMap actionMap = component.getActionMap(); //  Not all components have Actions defined
        Object[] keys = actionMap.allKeys();
        if (keys == null) {
            Object[] row = {"No actions found", "", "", ""};
            model.addRow(row);
            return;
        }
        //  In some ActionMaps a key of type Object is found (I have no idea why)
        //  which causes a ClassCastExcption when sorting so we will ignore it
        //  by converting that entry to the empty string
        for (int i = 0; i < keys.length; i++) {
            Object key = keys[i];
            if (key instanceof String) {
                continue;
            } else {
                keys[i] = "";
            }
        }
        Arrays.sort(keys);
        for (int i = 0; i < keys.length; i++) { //  Create a new row in the model for every Action found
            Object key = keys[i];
            if (key != "") {
                Object[] row = {key, "", "", ""};
                model.addRow(row);
            }
        }
        //  Now check each InputMap to see if a KeyStroke is bound the the Action
        updateModelForInputMap(model, 1, component.getInputMap(JComponent.WHEN_FOCUSED));
        updateModelForInputMap(model, 2, component.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW));
        updateModelForInputMap(model, 3, component.getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT));
    }

    /*
     *  The model is potentially update for each of the 3 different InputMaps
     */
    private void updateModelForInputMap(TableModel model, int column, InputMap inputMap) {
        if (inputMap == null) {
            return;
        }
        KeyStroke[] keys = inputMap.allKeys();
        if (keys == null) {
            return;
        }
        //  The InputMap is keyed by KeyStroke, however we want to be able to
        //  access the action names that are bound to a KeyStroke so we will create
        //  a Hashtble that is keyed by action name.
        //  Note that multiple KeyStrokes can be bound to the same action name.
        Hashtable<Object, String> actions = new Hashtable<Object, String>(keys.length);
        for (int i = 0; i < keys.length; i++) {
            KeyStroke key = keys[i];
            Object actionName = inputMap.get(key);
            Object value = actions.get(actionName);
            if (value == null) {
                actions.put(actionName, key.toString().replace("pressed ", ""));
            } else {
                actions.put(actionName, value + ", " + key.toString().replace("pressed ", ""));
            }
        }
        for (int i = 0; i < model.getRowCount(); i++) {
            //  Now we can update the model for those actions that have  KeyStrokes mapped to them
            String o = actions.get(model.getValueAt(i, 0));
            if (o != null) {
                model.setValueAt(o.toString(), i, column);
            }
        }
    }

    /*
     *  Change the LAF and recreate the UIManagerDefaults so that the properties
     *  of the new LAF are correctly displayed.
     */
    private class ChangeLookAndFeelAction extends AbstractAction {

        private static final long serialVersionUID = 1L;
        private String laf;

        protected ChangeLookAndFeelAction(String laf, String name) {
            this.laf = laf;
            putValue(Action.NAME, name);
            putValue(Action.SHORT_DESCRIPTION, getValue(Action.NAME));
        }

        @Override
        public void actionPerformed(ActionEvent e) {
            try {
                JMenuItem mi = (JMenuItem) e.getSource();
                JPopupMenu popup = (JPopupMenu) mi.getParent();
                JRootPane rootPane = SwingUtilities.getRootPane(popup.getInvoker());
                Component c = rootPane.getContentPane().getComponent(0);
                rootPane.getContentPane().remove(c);
                UIManager.setLookAndFeel(laf);
                KeyBindings bindings = new KeyBindings();
                rootPane.getContentPane().add(bindings.getContentPane());
                SwingUtilities.updateComponentTreeUI(rootPane);
                rootPane.requestFocusInWindow();
            } catch (Exception ex) {
                System.out.println("Failed loading L&F: " + laf);
                System.out.println(ex);
            }
        }
    }

    private class ExitAction extends AbstractAction {

        private static final long serialVersionUID = 1L;

        public ExitAction() {
            putValue(Action.NAME, "Exit");
            putValue(Action.SHORT_DESCRIPTION, getValue(Action.NAME));
            putValue(Action.MNEMONIC_KEY, new Integer(KeyEvent.VK_X));
        }

        @Override
        public void actionPerformed(ActionEvent e) {
            System.exit(0);
        }
    }

    private class DummyFileSystemView extends FileSystemView {

        @Override
        public File createNewFolder(File containingDir) {
            return null;
        }

        @Override
        public File getDefaultDirectory() {
            return null;
        }

        @Override
        public File getHomeDirectory() {
            return null;
        }
    }

    private static void createAndShowGUI() {
        KeyBindings application = new KeyBindings();
        JFrame.setDefaultLookAndFeelDecorated(true);
        JFrame frame = new JFrame("Key Bindings");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setJMenuBar(application.getMenuBar());
        frame.getContentPane().add(application.getContentPane());
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        //UIManager.put("swing.boldMetal", Boolean.FALSE);
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                createAndShowGUI();
            }
        });
    }
}