Choose Drop Action : Drag Drop « Swing « Java Tutorial






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import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Rectangle;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.StringSelection;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;

import javax.swing.BorderFactory;
import javax.swing.BoxLayout;
import javax.swing.DefaultListModel;
import javax.swing.DropMode;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.ListSelectionModel;
import javax.swing.SwingUtilities;
import javax.swing.TransferHandler;
import javax.swing.UIManager;

public class ChooseDropActionDemo extends JFrame {

  DefaultListModel from = new DefaultListModel();
  DefaultListModel copy = new DefaultListModel();
  DefaultListModel move = new DefaultListModel();
  JList dragFrom;

  public ChooseDropActionDemo() {
    super("ChooseDropActionDemo");

    for (int i = 15; i >= 0; i--) {
      from.add(0, "Source item " + i);
    }

    for (int i = 2; i >= 0; i--) {
      copy.add(0, "Target item " + i);
      move.add(0, "Target item " + i);
    }

    JPanel p = new JPanel();
    p.setLayout(new BoxLayout(p, BoxLayout.Y_AXIS));
    dragFrom = new JList(from);
    dragFrom.setTransferHandler(new FromTransferHandler());
    dragFrom.setPrototypeCellValue("List Item WWWWWW");
    dragFrom.setDragEnabled(true);
    dragFrom.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    JLabel label = new JLabel("Drag from here:");
    label.setAlignmentX(0f);
    p.add(label);
    JScrollPane sp = new JScrollPane(dragFrom);
    sp.setAlignmentX(0f);
    p.add(sp);
    add(p, BorderLayout.WEST);

    JList moveTo = new JList(move);
    moveTo.setTransferHandler(new ToTransferHandler(TransferHandler.COPY));
    moveTo.setDropMode(DropMode.INSERT);
    JList copyTo = new JList(copy);
    copyTo.setTransferHandler(new ToTransferHandler(TransferHandler.MOVE));
    copyTo.setDropMode(DropMode.INSERT);

    p = new JPanel();
    p.setLayout(new BoxLayout(p, BoxLayout.Y_AXIS));
    label = new JLabel("Drop to COPY to here:");
    ;
    label.setAlignmentX(0f);
    p.add(label);
    sp = new JScrollPane(moveTo);
    sp.setAlignmentX(0f);
    p.add(sp);
    label = new JLabel("Drop to MOVE to here:");
    label.setAlignmentX(0f);
    p.add(label);
    sp = new JScrollPane(copyTo);
    sp.setAlignmentX(0f);
    p.add(sp);
    p.setBorder(BorderFactory.createEmptyBorder(0, 2, 0, 0));
    add(p, BorderLayout.CENTER);

    ((JPanel) getContentPane()).setBorder(BorderFactory.createEmptyBorder(2, 2,
        2, 2));

    getContentPane().setPreferredSize(new Dimension(320, 315));
  }

  private static void createAndShowGUI() {
    // Create and set up the window.
    ChooseDropActionDemo test = new ChooseDropActionDemo();
    test.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

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

  public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        // Turn off metal's use of bold fonts
        UIManager.put("swing.boldMetal", Boolean.FALSE);
        createAndShowGUI();
      }
    });
  }

  class FromTransferHandler extends TransferHandler {
    public int getSourceActions(JComponent comp) {
      return COPY_OR_MOVE;
    }

    private int index = 0;

    public Transferable createTransferable(JComponent comp) {
      index = dragFrom.getSelectedIndex();
      if (index < 0 || index >= from.getSize()) {
        return null;
      }

      return new StringSelection((String) dragFrom.getSelectedValue());
    }

    public void exportDone(JComponent comp, Transferable trans, int action) {
      if (action != MOVE) {
        return;
      }

      from.removeElementAt(index);
    }
  }

  class ToTransferHandler extends TransferHandler {
    int action;

    public ToTransferHandler(int action) {
      this.action = action;
    }

    public boolean canImport(TransferHandler.TransferSupport support) {
      // for the demo, we'll only support drops (not clipboard paste)
      if (!support.isDrop()) {
        return false;
      }

      // we only import Strings
      if (!support.isDataFlavorSupported(DataFlavor.stringFlavor)) {
        return false;
      }

      boolean actionSupported = (action & support.getSourceDropActions()) == action;
      if (actionSupported) {
        support.setDropAction(action);
        return true;
      }

      return false;
    }

    public boolean importData(TransferHandler.TransferSupport support) {
      // if we can't handle the import, say so
      if (!canImport(support)) {
        return false;
      }

      // fetch the drop location
      JList.DropLocation dl = (JList.DropLocation) support.getDropLocation();

      int index = dl.getIndex();

      // fetch the data and bail if this fails
      String data;
      try {
        data = (String) support.getTransferable().getTransferData(
            DataFlavor.stringFlavor);
      } catch (UnsupportedFlavorException e) {
        return false;
      } catch (java.io.IOException e) {
        return false;
      }

      JList list = (JList) support.getComponent();
      DefaultListModel model = (DefaultListModel) list.getModel();
      model.insertElementAt(data, index);

      Rectangle rect = list.getCellBounds(index, index);
      list.scrollRectToVisible(rect);
      list.setSelectedIndex(index);
      list.requestFocusInWindow();

      return true;
    }
  }
}








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