Basic drag and drop : Drag Drop « Swing « Java Tutorial






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/*
 * BasicDnD.java requires no other files.
 */

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.StringSelection;
import java.awt.datatransfer.Transferable;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.BorderFactory;
import javax.swing.BoxLayout;
import javax.swing.DefaultListModel;
import javax.swing.DropMode;
import javax.swing.JCheckBox;
import javax.swing.JColorChooser;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTable;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.JTree;
import javax.swing.ListSelectionModel;
import javax.swing.SwingUtilities;
import javax.swing.TransferHandler;
import javax.swing.UIManager;
import javax.swing.table.DefaultTableModel;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreeSelectionModel;

public class BasicDnD extends JPanel implements ActionListener {
  private static JFrame frame;
  private JTextArea textArea;
  private JTextField textField;
  private JList list;
  private JTable table;
  private JTree tree;
  private JColorChooser colorChooser;
  private JCheckBox toggleDnD;

  public BasicDnD() {
    super(new BorderLayout());
    JPanel leftPanel = createVerticalBoxPanel();
    JPanel rightPanel = createVerticalBoxPanel();

    // Create a table model.
    DefaultTableModel tm = new DefaultTableModel();
    tm.addColumn("Column 0");
    tm.addColumn("Column 1");
    tm.addColumn("Column 2");
    tm.addColumn("Column 3");
    tm.addRow(new String[] { "Table 00", "Table 01", "Table 02", "Table 03" });
    tm.addRow(new String[] { "Table 10", "Table 11", "Table 12", "Table 13" });
    tm.addRow(new String[] { "Table 20", "Table 21", "Table 22", "Table 23" });
    tm.addRow(new String[] { "Table 30", "Table 31", "Table 32", "Table 33" });

    // LEFT COLUMN
    // Use the table model to create a table.
    table = new JTable(tm);
    leftPanel.add(createPanelForComponent(table, "JTable"));

    // Create a color chooser.
    colorChooser = new JColorChooser();
    leftPanel.add(createPanelForComponent(colorChooser, "JColorChooser"));

    // RIGHT COLUMN
    // Create a textfield.
    textField = new JTextField(30);
    textField.setText("Favorite foods:\nPizza, Moussaka, Pot roast");
    rightPanel.add(createPanelForComponent(textField, "JTextField"));

    // Create a scrolled text area.
    textArea = new JTextArea(5, 30);
    textArea.setText("Favorite shows:\nBuffy, Alias, Angel");
    JScrollPane scrollPane = new JScrollPane(textArea);
    rightPanel.add(createPanelForComponent(scrollPane, "JTextArea"));

    // Create a list model and a list.
    DefaultListModel listModel = new DefaultListModel();
    listModel.addElement("Martha Washington");
    listModel.addElement("Abigail Adams");
    listModel.addElement("Martha Randolph");
    listModel.addElement("Dolley Madison");
    listModel.addElement("Elizabeth Monroe");
    listModel.addElement("Louisa Adams");
    listModel.addElement("Emily Donelson");
    list = new JList(listModel);
    list.setVisibleRowCount(-1);
    list.getSelectionModel().setSelectionMode(
        ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);

    list.setTransferHandler(new TransferHandler() {

      public boolean canImport(TransferHandler.TransferSupport info) {
        // we only import Strings
        if (!info.isDataFlavorSupported(DataFlavor.stringFlavor)) {
          return false;
        }

        JList.DropLocation dl = (JList.DropLocation) info.getDropLocation();
        if (dl.getIndex() == -1) {
          return false;
        }
        return true;
      }

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

        // Check for String flavor
        if (!info.isDataFlavorSupported(DataFlavor.stringFlavor)) {
          displayDropLocation("List doesn't accept a drop of this type.");
          return false;
        }

        JList.DropLocation dl = (JList.DropLocation) info.getDropLocation();
        DefaultListModel listModel = (DefaultListModel) list.getModel();
        int index = dl.getIndex();
        boolean insert = dl.isInsert();
        // Get the current string under the drop.
        String value = (String) listModel.getElementAt(index);

        // 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;
        }

        // Display a dialog with the drop information.
        String dropValue = "\"" + data + "\" dropped ";
        if (dl.isInsert()) {
          if (dl.getIndex() == 0) {
            displayDropLocation(dropValue + "at beginning of list");
          } else if (dl.getIndex() >= list.getModel().getSize()) {
            displayDropLocation(dropValue + "at end of list");
          } else {
            String value1 = (String) list.getModel().getElementAt(
                dl.getIndex() - 1);
            String value2 = (String) list.getModel()
                .getElementAt(dl.getIndex());
            displayDropLocation(dropValue + "between \"" + value1 + "\" and \""
                + value2 + "\"");
          }
        } else {
          displayDropLocation(dropValue + "on top of " + "\"" + value + "\"");
        }

        /**
         * This is commented out for the basicdemo.html tutorial page. * If you
         * add this code snippet back and delete the * "return false;" line, the
         * list will accept drops * of type string. // Perform the actual
         * import. if (insert) { listModel.add(index, data); } else {
         * listModel.set(index, data); } return true;
         */
        return false;
      }

      public int getSourceActions(JComponent c) {
        return COPY;
      }

      protected Transferable createTransferable(JComponent c) {
        JList list = (JList) c;
        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 new StringSelection(buff.toString());
      }
    });
    list.setDropMode(DropMode.ON_OR_INSERT);

    JScrollPane listView = new JScrollPane(list);
    listView.setPreferredSize(new Dimension(300, 100));
    rightPanel.add(createPanelForComponent(listView, "JList"));

    // Create a tree.
    DefaultMutableTreeNode rootNode = new DefaultMutableTreeNode("Mia Familia");
    DefaultMutableTreeNode sharon = new DefaultMutableTreeNode("Sharon");
    rootNode.add(sharon);
    DefaultMutableTreeNode maya = new DefaultMutableTreeNode("Maya");
    sharon.add(maya);
    DefaultMutableTreeNode anya = new DefaultMutableTreeNode("Anya");
    sharon.add(anya);
    sharon.add(new DefaultMutableTreeNode("Bongo"));
    maya.add(new DefaultMutableTreeNode("Muffin"));
    anya.add(new DefaultMutableTreeNode("Winky"));
    DefaultTreeModel model = new DefaultTreeModel(rootNode);
    tree = new JTree(model);
    tree.getSelectionModel().setSelectionMode(
        TreeSelectionModel.DISCONTIGUOUS_TREE_SELECTION);
    JScrollPane treeView = new JScrollPane(tree);
    treeView.setPreferredSize(new Dimension(300, 100));
    rightPanel.add(createPanelForComponent(treeView, "JTree"));

    // Create the toggle button.
    toggleDnD = new JCheckBox("Turn on Drag and Drop");
    toggleDnD.setActionCommand("toggleDnD");
    toggleDnD.addActionListener(this);

    JSplitPane splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,
        leftPanel, rightPanel);
    splitPane.setOneTouchExpandable(true);

    add(splitPane, BorderLayout.CENTER);
    add(toggleDnD, BorderLayout.PAGE_END);
    setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
  }

  protected JPanel createVerticalBoxPanel() {
    JPanel p = new JPanel();
    p.setLayout(new BoxLayout(p, BoxLayout.PAGE_AXIS));
    p.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
    return p;
  }

  public JPanel createPanelForComponent(JComponent comp, String title) {
    JPanel panel = new JPanel(new BorderLayout());
    panel.add(comp, BorderLayout.CENTER);
    if (title != null) {
      panel.setBorder(BorderFactory.createTitledBorder(title));
    }
    return panel;
  }

  private void displayDropLocation(final String string) {
    SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        JOptionPane.showMessageDialog(null, string);
      }
    });
  }

  public void actionPerformed(ActionEvent e) {
    if ("toggleDnD".equals(e.getActionCommand())) {
      boolean toggle = toggleDnD.isSelected();
      textArea.setDragEnabled(toggle);
      textField.setDragEnabled(toggle);
      list.setDragEnabled(toggle);
      table.setDragEnabled(toggle);
      tree.setDragEnabled(toggle);
      colorChooser.setDragEnabled(toggle);
    }
  }

  /**
   * 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.
    frame = new JFrame("BasicDnD");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    // Create and set up the content pane.
    JComponent newContentPane = new BasicDnD();
    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();
      }
    });
  }
}








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