Java tutorial
/* From http://java.sun.com/docs/books/tutorial/index.html */ /* * Copyright (c) 2006 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: * * -Redistribution of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * -Redistribution 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, Inc. or the names of contributors may * be used to endorse or promote products derived from this software without * specific prior written permission. * * This software is provided "AS IS," without a warranty of any kind. ALL * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN") * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. * * You acknowledge that this software is not designed, licensed or intended * for use in the design, construction, operation or maintenance of any * nuclear facility. */ /* * DragColorDemo.java is a 1.4 example that requires * the following file: * ColorTransferHandler.java */ import java.awt.BorderLayout; import java.awt.Color; import java.awt.GridLayout; import java.awt.datatransfer.DataFlavor; import java.awt.datatransfer.Transferable; import java.awt.datatransfer.UnsupportedFlavorException; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.io.IOException; import javax.swing.BorderFactory; import javax.swing.JButton; import javax.swing.JCheckBox; import javax.swing.JColorChooser; import javax.swing.JComponent; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.TransferHandler; /** * Example code that shows any JComponent can be customized to allow dropping of * a color. */ public class DragColorDemo extends JPanel implements ActionListener { JCheckBox toggleForeground; ColorTransferHandler colorHandler; public DragColorDemo() { super(new BorderLayout()); setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20)); JColorChooser chooser = new JColorChooser(); chooser.setDragEnabled(true); add(chooser, BorderLayout.PAGE_START); //Create the color transfer handler. colorHandler = new ColorTransferHandler(); //Create a matrix of 9 buttons. JPanel buttonPanel = new JPanel(new GridLayout(3, 3)); for (int i = 0; i < 9; i++) { JButton tmp = new JButton("Button " + i); tmp.setTransferHandler(colorHandler); buttonPanel.add(tmp); } add(buttonPanel, BorderLayout.CENTER); //Create a check box. toggleForeground = new JCheckBox("Change the foreground color."); toggleForeground.setSelected(true); toggleForeground.addActionListener(this); JPanel textPanel = new JPanel(new BorderLayout()); textPanel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5)); textPanel.add(toggleForeground, BorderLayout.PAGE_START); //Create a label. JLabel label = new JLabel("Change the color of any button or this label by dropping a color."); label.setTransferHandler(colorHandler); label.setOpaque(true); //So the background color can be changed. textPanel.add(label, BorderLayout.PAGE_END); add(textPanel, BorderLayout.PAGE_END); } public void actionPerformed(ActionEvent e) { colorHandler.setChangesForegroundColor(toggleForeground.isSelected()); } /** * Create the GUI and show it. For thread safety, this method should be * invoked from the event-dispatching thread. */ private static void createAndShowGUI() { //Make sure we have nice window decorations. JFrame.setDefaultLookAndFeelDecorated(true); //Create and set up the window. JFrame frame = new JFrame("DragColorDemo"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Create and setup the content pane. JComponent newContentPane = new DragColorDemo(); 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() { createAndShowGUI(); } }); } } /* * ColorTransferHandler.java is used by the 1.4 DragColorDemo.java and * DragColorTextFieldDemo examples. */ /** * An implementation of TransferHandler that adds support for dropping colors. * Dropping a color on a component having this TransferHandler changes the * foreground or the background of the component to the dropped color, according * to the value of the changesForegroundColor property. */ class ColorTransferHandler extends TransferHandler { //The data type exported from JColorChooser. String mimeType = DataFlavor.javaJVMLocalObjectMimeType + ";class=java.awt.Color"; DataFlavor colorFlavor; private boolean changesForegroundColor = true; ColorTransferHandler() { //Try to create a DataFlavor for color. try { colorFlavor = new DataFlavor(mimeType); } catch (ClassNotFoundException e) { } } /** * Overridden to import a Color if it is available. * getChangesForegroundColor is used to determine whether the foreground or * the background color is changed. */ public boolean importData(JComponent c, Transferable t) { if (hasColorFlavor(t.getTransferDataFlavors())) { try { Color col = (Color) t.getTransferData(colorFlavor); if (getChangesForegroundColor()) { c.setForeground(col); } else { c.setBackground(col); } return true; } catch (UnsupportedFlavorException ufe) { System.out.println("importData: unsupported data flavor"); } catch (IOException ioe) { System.out.println("importData: I/O exception"); } } return false; } /** * Does the flavor list have a Color flavor? */ protected boolean hasColorFlavor(DataFlavor[] flavors) { if (colorFlavor == null) { return false; } for (int i = 0; i < flavors.length; i++) { if (colorFlavor.equals(flavors[i])) { return true; } } return false; } /** * Overridden to include a check for a color flavor. */ public boolean canImport(JComponent c, DataFlavor[] flavors) { return hasColorFlavor(flavors); } protected void setChangesForegroundColor(boolean flag) { changesForegroundColor = flag; } protected boolean getChangesForegroundColor() { return changesForegroundColor; } }