Various drop actions : Drag Drop « Swing « Java Tutorial






/*
 * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Sun Microsystems nor the names of its
 *     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
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */ 


/*
 * DropDemo.java requires the following file:
 *     ListTransferHandler.java
 */
import javax.swing.*;
import java.awt.*;
import java.awt.datatransfer.*;
import java.awt.event.*;


public class DropDemo extends JPanel implements ActionListener {
    private JComboBox dropCombo;
    private JList list;
    
    public DropDemo() {
        super(new GridLayout(2,1));
        add(createArea());
        add(createList());
    }
    
    private JPanel createList() {
        DefaultListModel listModel = new DefaultListModel();
            
        for (int i = 0; i < 10; i++) {
            listModel.addElement("List Item " + i);
        }
        
        list = new JList(listModel);
        list.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
        JScrollPane scrollPane = new JScrollPane(list);
        scrollPane.setPreferredSize(new Dimension(400,100));
        
        list.setDragEnabled(true);
        list.setTransferHandler(new ListTransferHandler());
        
        dropCombo = new JComboBox(new String[] {"USE_SELECTION", "ON", "INSERT", "ON_OR_INSERT"});
        dropCombo.addActionListener(this);
        JPanel dropPanel = new JPanel();
        dropPanel.add(new JLabel("List Drop Mode:"));
        dropPanel.add(dropCombo);
        
        JPanel panel = new JPanel(new BorderLayout());
        panel.add(scrollPane, BorderLayout.CENTER);
        panel.add(dropPanel, BorderLayout.SOUTH);
        panel.setBorder(BorderFactory.createTitledBorder("List"));
        return panel;
    }
    
    private JPanel createArea() {
        String text = "Drag from or drop into this area.\nThe default action is MOVE;\nhold the Control key to COPY.";
        
        JTextArea area = new JTextArea();
        area.setText(text);
        area.setDragEnabled(true);
        JScrollPane scrollPane = new JScrollPane(area);
        scrollPane.setPreferredSize(new Dimension(400,100));
        JPanel panel = new JPanel(new BorderLayout());
        panel.add(scrollPane, BorderLayout.CENTER);
        panel.setBorder(BorderFactory.createTitledBorder("Text Area"));
        return panel;
    }

    public void actionPerformed(ActionEvent ae) {
        Object val = dropCombo.getSelectedItem();
        if (val == "USE_SELECTION") {
            list.setDropMode(DropMode.USE_SELECTION);
        } else if (val == "ON") {
            list.setDropMode(DropMode.ON);
        } else if (val == "INSERT") {
            list.setDropMode(DropMode.INSERT);
        } else if (val == "ON_OR_INSERT") {
            list.setDropMode(DropMode.ON_OR_INSERT);
        }
    }

    /**
     * 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("DropDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create and set up the content pane.
        JComponent newContentPane = new DropDemo();
        newContentPane.setOpaque(true); //content panes must be opaque
        frame.setContentPane(newContentPane);

        //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();
            }
        });
    }
}

/*
 * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Sun Microsystems nor the names of its
 *     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
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * ListTransferHandler.java is used by the DropDemo example.
 */


class ListTransferHandler extends TransferHandler {
  private int[] indices = null;
  private int addIndex = -1; // Location where items were added
  private int addCount = 0; // Number of items added.

  public boolean canImport(TransferHandler.TransferSupport info) {
    // Check for String flavor
    if (!info.isDataFlavorSupported(DataFlavor.stringFlavor)) {
      return false;
    }
    return true;
  }

  protected Transferable createTransferable(JComponent c) {
    return new StringSelection(exportString(c));
  }

  public int getSourceActions(JComponent c) {
    return TransferHandler.COPY_OR_MOVE;
  }

  public boolean importData(TransferHandler.TransferSupport info) {
    if (!info.isDrop()) {
      return false;
    }

    JList list = (JList) info.getComponent();
    DefaultListModel listModel = (DefaultListModel) list.getModel();
    JList.DropLocation dl = (JList.DropLocation) info.getDropLocation();
    int index = dl.getIndex();
    boolean insert = dl.isInsert();

    // Get the string that is being dropped.
    Transferable t = info.getTransferable();
    String data;
    try {
      data = (String) t.getTransferData(DataFlavor.stringFlavor);
    } catch (Exception e) {
      return false;
    }

    // Perform the actual import.
    if (insert) {
      listModel.add(index, data);
    } else {
      listModel.set(index, data);
    }
    return true;
  }

  protected void exportDone(JComponent c, Transferable data, int action) {
    cleanup(c, action == TransferHandler.MOVE);
  }

  // Bundle up the selected items in the list
  // as a single string, for export.
  protected String exportString(JComponent c) {
    JList list = (JList) c;
    indices = list.getSelectedIndices();
    Object[] values = list.getSelectedValues();

    StringBuffer buff = new StringBuffer();

    for (int i = 0; i < values.length; i++) {
      Object val = values[i];
      buff.append(val == null ? "" : val.toString());
      if (i != values.length - 1) {
        buff.append("\n");
      }
    }

    return buff.toString();
  }

  // Take the incoming string and wherever there is a
  // newline, break it into a separate item in the list.
  protected void importString(JComponent c, String str) {
    JList target = (JList) c;
    DefaultListModel listModel = (DefaultListModel) target.getModel();
    int index = target.getSelectedIndex();

    // Prevent the user from dropping data back on itself.
    // For example, if the user is moving items #4,#5,#6 and #7 and
    // attempts to insert the items after item #5, this would
    // be problematic when removing the original items.
    // So this is not allowed.
    if (indices != null && index >= indices[0] - 1
        && index <= indices[indices.length - 1]) {
      indices = null;
      return;
    }

    int max = listModel.getSize();
    if (index < 0) {
      index = max;
    } else {
      index++;
      if (index > max) {
        index = max;
      }
    }
    addIndex = index;
    String[] values = str.split("\n");
    addCount = values.length;
    for (int i = 0; i < values.length; i++) {
      listModel.add(index++, values[i]);
    }
  }

  // If the remove argument is true, the drop has been
  // successful and it's time to remove the selected items
  // from the list. If the remove argument is false, it
  // was a Copy operation and the original list is left
  // intact.
  protected void cleanup(JComponent c, boolean remove) {
    if (remove && indices != null) {
      JList source = (JList) c;
      DefaultListModel model = (DefaultListModel) source.getModel();
      // If we are moving items around in the same list, we
      // need to adjust the indices accordingly, since those
      // after the insertion point have moved.
      if (addCount > 0) {
        for (int i = 0; i < indices.length; i++) {
          if (indices[i] > addIndex) {
            indices[i] += addCount;
          }
        }
      }
      for (int i = indices.length - 1; i >= 0; i--) {
        model.remove(indices[i]);
      }
    }
    indices = null;
    addCount = 0;
    addIndex = -1;
  }
}








14.112.Drag Drop
14.112.1.Basic drag and drop
14.112.2.Dragging Text from a JLabelDragging Text from a JLabel
14.112.3.Drag-and-Drop Support for ImagesDrag-and-Drop Support for Images
14.112.4.Drag and drop icons: use an icon property.
14.112.5.implements DragGestureListener, Transferable
14.112.6.Dragging and dropping text between a text area, a list, and a tableDragging and dropping text between a text area, a list, and a table
14.112.7.Drag and drop between JTextArea and JTextField
14.112.8.Transfer both Text and Color between JTextField and JTextArea
14.112.9.Drag and drop between JList and JTextField
14.112.10.DropMode.ON
14.112.11.DropMode.INSERT
14.112.12.DropMode.ON_OR_INSERT
14.112.13.Set tree DropMode to DropMode.USE_SELECTION
14.112.14.Set tree drag mode to DropMode.ON
14.112.15.Set tree drag mode to DropMode.INSERT
14.112.16.Set tree drag mode to DropMode.ON_OR_INSERT
14.112.17.Choose Drop Action
14.112.18.Various drop actions
14.112.19.JTable drag and drop
14.112.20.Create a drag source a drop target and a transferable object.
14.112.21.Making a Component Draggable
14.112.22.Detect a drag initiating gesture in your application
14.112.23.Illustrates cut, copy, paste and drag and drop using three instances of JList
14.112.24.Location sensitive drag and drop
14.112.25.Demonstration of the top-level TransferHandler support on JFrame
14.112.26.Drag-and-Drop customization: drag the foreground color from the first label and drop it as the background color into the second one
14.112.27.Demonstrates how to add copy and drag support to a Swing component with TransferHandler
14.112.28.ScribblePane allows individual PolyLine lines to be selected, cut, copied, pasted, dragged, and dropped
14.112.29.Built-in drag and drop support: utilize a TransferHandler class
14.112.30.DND Drag and drop List