DnDDemo3.java Source code

Introduction

Here is the source code for DnDDemo3.java

Source

import java.awt.BorderLayout;
import java.awt.Rectangle;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;

import javax.swing.DefaultListModel;
import javax.swing.DropMode;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.TransferHandler;

public class DnDDemo3 {
    public static void main(String[] args) {
        JPanel north = new JPanel();
        north.add(new JLabel("Drag from here:"));
        JTextField field = new JTextField(10);
        field.setDragEnabled(true);
        north.add(field);

        final DefaultListModel listModel = new DefaultListModel();
        listModel.addElement("first");
        listModel.addElement("second");
        final JList list = new JList(listModel);
        list.setDragEnabled(true);

        list.setTransferHandler(new TransferHandler() {
            public boolean canImport(TransferHandler.TransferSupport support) {
                if (!support.isDataFlavorSupported(DataFlavor.stringFlavor)) {
                    return false;
                }
                JList.DropLocation dl = (JList.DropLocation) support.getDropLocation();
                if (dl.getIndex() == -1) {
                    return false;
                } else {
                    return true;
                }
            }

            public boolean importData(TransferHandler.TransferSupport support) {
                if (!canImport(support)) {
                    return false;
                }

                Transferable transferable = support.getTransferable();
                String data;
                try {
                    data = (String) transferable.getTransferData(DataFlavor.stringFlavor);
                } catch (Exception e) {
                    return false;
                }

                JList.DropLocation dl = (JList.DropLocation) support.getDropLocation();
                int index = dl.getIndex();
                if (dl.isInsert()) {
                    listModel.add(index, data);
                } else {
                    listModel.set(index, data);
                }
                Rectangle r = list.getCellBounds(index, index);
                list.scrollRectToVisible(r);
                return true;
            }
        });
        JScrollPane center = new JScrollPane();
        center.setViewportView(list);

        list.setDropMode(DropMode.USE_SELECTION);
        JPanel cp = new JPanel();
        cp.setLayout(new BorderLayout());
        cp.add(north, BorderLayout.NORTH);
        cp.add(center, BorderLayout.CENTER);
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setContentPane(cp);
        frame.pack();
        frame.setVisible(true);
    }
}