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; } }