Cut, copy, paste and drag and drop using three instances of JList - Java Swing

Java examples for Swing:JList

Description

Cut, copy, paste and drag and drop using three instances of JList

Demo Code

/**//w ww  .  java 2 s. c  o  m
 * ListCutPaste.java requires the following files:
 *     ListTransferHandler.java
 *     TransferActionListener.java
 */
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.datatransfer.*;
import java.awt.dnd.*;
import javax.swing.*;

/**
 * The ListCutPaste example illustrates cut, copy, paste
 * and drag and drop using three instances of JList.
 * The TransferActionListener class listens for one of
 * the CCP actions and, when one occurs, forwards the
 * action to the component which currently has the focus.
 */
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.beans.*;
import java.io.*;
import java.awt.*;
import java.awt.datatransfer.*;
import java.awt.event.*;
import javax.swing.*;

class ListTransferHandler extends TransferHandler {

    /**
     * Perform the actual data import.
     */
    public boolean importData(TransferHandler.TransferSupport info) {
        String data = null;

        //If we can't handle the import, bail now.
        if (!canImport(info)) {
            return false;
        }

        JList list = (JList) info.getComponent();
        DefaultListModel model = (DefaultListModel) list.getModel();
        //Fetch the data -- bail if this fails
        try {
            data = (String) info.getTransferable().getTransferData(
                    DataFlavor.stringFlavor);
        } catch (UnsupportedFlavorException ufe) {
            System.out.println("importData: unsupported data flavor");
            return false;
        } catch (IOException ioe) {
            System.out.println("importData: I/O exception");
            return false;
        }

        if (info.isDrop()) { //This is a drop
            JList.DropLocation dl = (JList.DropLocation) info
                    .getDropLocation();
            int index = dl.getIndex();
            if (dl.isInsert()) {
                model.add(index, data);
                return true;
            } else {
                model.set(index, data);
                return true;
            }
        } else { //This is a paste
            int index = list.getSelectedIndex();
            // if there is a valid selection,
            // insert data after the selection
            if (index >= 0) {
                model.add(list.getSelectedIndex() + 1, data);
                // else append to the end of the list
            } else {
                model.addElement(data);
            }
            return true;
        }
    }

    /**
     * Bundle up the data for export.
     */
    protected Transferable createTransferable(JComponent c) {
        JList list = (JList) c;
        int index = list.getSelectedIndex();
        String value = (String) list.getSelectedValue();
        return new StringSelection(value);
    }

    /**
     * The list handles both copy and move actions.
     */
    public int getSourceActions(JComponent c) {
        return COPY_OR_MOVE;
    }

    /** 
     * When the export is complete, remove the old list entry if the
     * action was a move.
     */
    protected void exportDone(JComponent c, Transferable data, int action) {
        if (action != MOVE) {
            return;
        }
        JList list = (JList) c;
        DefaultListModel model = (DefaultListModel) list.getModel();
        int index = list.getSelectedIndex();
        model.remove(index);
    }

    /**
     * We only support importing strings.
     */
    public boolean canImport(TransferHandler.TransferSupport support) {
        // we only import Strings
        if (!support.isDataFlavorSupported(DataFlavor.stringFlavor)) {
            return false;
        }
        return true;
    }
}

/**
 * A class that tracks the focused component.  This is necessary
 * to delegate the menu cut/copy/paste commands to the right
 * component.  An instance of this class is listening and
 * when the user fires one of these commands, it calls the
 * appropriate action on the currently focused component.
 */
class TransferActionListener implements ActionListener,
        PropertyChangeListener {
    private JComponent focusOwner = null;

    public TransferActionListener() {
        KeyboardFocusManager manager = KeyboardFocusManager
                .getCurrentKeyboardFocusManager();
        manager.addPropertyChangeListener("permanentFocusOwner", this);
    }

    public void propertyChange(PropertyChangeEvent e) {
        Object o = e.getNewValue();
        if (o instanceof JComponent) {
            focusOwner = (JComponent) o;
        } else {
            focusOwner = null;
        }
    }

    public void actionPerformed(ActionEvent e) {
        if (focusOwner == null)
            return;
        String action = (String) e.getActionCommand();
        Action a = focusOwner.getActionMap().get(action);
        if (a != null) {
            a.actionPerformed(new ActionEvent(focusOwner,
                    ActionEvent.ACTION_PERFORMED, null));
        }
    }
}

public class ListCutPaste extends JPanel {
    ListTransferHandler lh;

    public ListCutPaste() {
        super(new BorderLayout());
        lh = new ListTransferHandler();

        JPanel panel = new JPanel(new GridLayout(1, 3));
        DefaultListModel list1Model = new DefaultListModel();
        list1Model.addElement("alpha");
        list1Model.addElement("beta");
        list1Model.addElement("gamma");
        list1Model.addElement("delta");
        list1Model.addElement("epsilon");
        list1Model.addElement("zeta");
        JList list1 = new JList(list1Model);
        list1.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        JScrollPane sp1 = new JScrollPane(list1);
        sp1.setPreferredSize(new Dimension(400, 100));
        list1.setDragEnabled(true);
        list1.setTransferHandler(lh);
        list1.setDropMode(DropMode.ON_OR_INSERT);
        setMappings(list1);
        JPanel pan1 = new JPanel(new BorderLayout());
        pan1.add(sp1, BorderLayout.CENTER);
        pan1.setBorder(BorderFactory.createTitledBorder("Greek Alphabet"));
        panel.add(pan1);

        DefaultListModel list2Model = new DefaultListModel();
        list2Model.addElement("uma");
        list2Model.addElement("dois");
        list2Model.addElement("tres");
        list2Model.addElement("quatro");
        list2Model.addElement("cinco");
        list2Model.addElement("seis");
        JList list2 = new JList(list2Model);
        list2.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        list2.setDragEnabled(true);
        JScrollPane sp2 = new JScrollPane(list2);
        sp2.setPreferredSize(new Dimension(400, 100));
        list2.setTransferHandler(lh);
        list2.setDropMode(DropMode.INSERT);
        setMappings(list2);
        JPanel pan2 = new JPanel(new BorderLayout());
        pan2.add(sp2, BorderLayout.CENTER);
        pan2.setBorder(BorderFactory
                .createTitledBorder("Portuguese Numbers"));
        panel.add(pan2);

        DefaultListModel list3Model = new DefaultListModel();
        list3Model.addElement("adeen");
        list3Model.addElement("dva");
        list3Model.addElement("tri");
        list3Model.addElement("chyetirye");
        list3Model.addElement("pyat");
        list3Model.addElement("shest");
        JList list3 = new JList(list3Model);
        list3.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        list3.setDragEnabled(true);
        JScrollPane sp3 = new JScrollPane(list3);
        sp3.setPreferredSize(new Dimension(400, 100));
        list3.setTransferHandler(lh);
        list3.setDropMode(DropMode.ON);
        setMappings(list3);
        JPanel pan3 = new JPanel(new BorderLayout());
        pan3.add(sp3, BorderLayout.CENTER);
        pan3.setBorder(BorderFactory.createTitledBorder("Russian Numbers"));
        panel.add(pan3);

        setPreferredSize(new Dimension(500, 200));
        add(panel, BorderLayout.CENTER);
    }

    /**
     * Create an Edit menu to support cut/copy/paste.
     */
    public JMenuBar createMenuBar() {
        JMenuItem menuItem = null;
        JMenuBar menuBar = new JMenuBar();
        JMenu mainMenu = new JMenu("Edit");
        mainMenu.setMnemonic(KeyEvent.VK_E);
        TransferActionListener actionListener = new TransferActionListener();

        menuItem = new JMenuItem("Cut");
        menuItem.setActionCommand((String) TransferHandler.getCutAction()
                .getValue(Action.NAME));
        menuItem.addActionListener(actionListener);
        menuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_X,
                ActionEvent.CTRL_MASK));
        menuItem.setMnemonic(KeyEvent.VK_T);
        mainMenu.add(menuItem);

        menuItem = new JMenuItem("Copy");
        menuItem.setActionCommand((String) TransferHandler.getCopyAction()
                .getValue(Action.NAME));
        menuItem.addActionListener(actionListener);
        menuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_C,
                ActionEvent.CTRL_MASK));
        menuItem.setMnemonic(KeyEvent.VK_C);
        mainMenu.add(menuItem);

        menuItem = new JMenuItem("Paste");
        menuItem.setActionCommand((String) TransferHandler.getPasteAction()
                .getValue(Action.NAME));
        menuItem.addActionListener(actionListener);
        menuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_V,
                ActionEvent.CTRL_MASK));
        menuItem.setMnemonic(KeyEvent.VK_P);
        mainMenu.add(menuItem);

        menuBar.add(mainMenu);
        return menuBar;
    }

    /**
     * Add the cut/copy/paste actions to the action map.
     */
    private void setMappings(JList list) {
        ActionMap map = list.getActionMap();
        map.put(TransferHandler.getCutAction().getValue(Action.NAME),
                TransferHandler.getCutAction());
        map.put(TransferHandler.getCopyAction().getValue(Action.NAME),
                TransferHandler.getCopyAction());
        map.put(TransferHandler.getPasteAction().getValue(Action.NAME),
                TransferHandler.getPasteAction());

    }

    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("ListCutPaste");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create and set up the menu bar and content pane.
        ListCutPaste demo = new ListCutPaste();
        frame.setJMenuBar(demo.createMenuBar());
        demo.setOpaque(true); //content panes must be opaque
        frame.setContentPane(demo);

        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                //Turn off metal's use of bold fonts
                UIManager.put("swing.boldMetal", Boolean.FALSE);
                createAndShowGUI();
            }
        });
    }
}

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 *
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 *
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 *
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 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
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