Drag File Demo
/* 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,
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* You acknowledge that this software is not designed, licensed or intended
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*/
/*
* DragFileDemo.java is a 1.4 example that requires the following file:
* FileAndTextTransferHandler.java TabbedPaneController.java
*/
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Insets;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.StringSelection;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTabbedPane;
import javax.swing.JTextArea;
import javax.swing.TransferHandler;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.JTextComponent;
import javax.swing.text.Position;
public class DragFileDemo extends JPanel implements ActionListener {
JTextArea fileArea;
JFileChooser fc;
JButton clear;
TabbedPaneController tpc;
public DragFileDemo() {
super(new BorderLayout());
fc = new JFileChooser();
;
fc.setMultiSelectionEnabled(true);
fc.setDragEnabled(true);
fc.setControlButtonsAreShown(false);
JPanel fcPanel = new JPanel(new BorderLayout());
fcPanel.add(fc, BorderLayout.CENTER);
clear = new JButton("Clear All");
clear.addActionListener(this);
JPanel buttonPanel = new JPanel(new BorderLayout());
buttonPanel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
buttonPanel.add(clear, BorderLayout.LINE_END);
JPanel upperPanel = new JPanel(new BorderLayout());
upperPanel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
upperPanel.add(fcPanel, BorderLayout.CENTER);
upperPanel.add(buttonPanel, BorderLayout.PAGE_END);
//The TabbedPaneController manages the panel that
//contains the tabbed pane. When there are no files
//the panel contains a plain text area. Then, as
//files are dropped onto the area, the tabbed panel
//replaces the file area.
JTabbedPane tabbedPane = new JTabbedPane();
JPanel tabPanel = new JPanel(new BorderLayout());
tabPanel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
tpc = new TabbedPaneController(tabbedPane, tabPanel);
JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT,
upperPanel, tabPanel);
splitPane.setDividerLocation(400);
splitPane.setPreferredSize(new Dimension(530, 650));
add(splitPane, BorderLayout.CENTER);
}
public void setDefaultButton() {
getRootPane().setDefaultButton(clear);
}
public void actionPerformed(ActionEvent e) {
if (e.getSource() == clear) {
tpc.clearAll();
}
}
/**
* 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("DragFileDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Create and set up the menu bar and content pane.
DragFileDemo demo = new DragFileDemo();
demo.setOpaque(true); //content panes must be opaque
frame.setContentPane(demo);
//Display the window.
frame.pack();
frame.setVisible(true);
demo.setDefaultButton();
}
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();
}
});
}
}
/*
* TabbedPaneController.java is used by the 1.4 DragFileDemo.java example.
*/
/*
* Class that manages area where the contents of files are displayed. When no
* files are present, there is a simple JTextArea instructing users to drop a
* file. As soon as a file is dropped, a JTabbedPane is placed into the window
* and each file is displayed under its own tab. When all the files are removed,
* the JTabbedPane is removed from the window and the simple JTextArea is again
* displayed.
*/
class TabbedPaneController {
JPanel tabbedPanel = null;
JTabbedPane tabbedPane;
JPanel emptyFilePanel = null;
JTextArea emptyFileArea = null;
FileAndTextTransferHandler transferHandler;
boolean noFiles = true;
String fileSeparator;
public TabbedPaneController(JTabbedPane tb, JPanel tp) {
tabbedPane = tb;
tabbedPanel = tp;
transferHandler = new FileAndTextTransferHandler(this);
fileSeparator = System.getProperty("file.separator");
//The split method in the String class uses
//regular expressions to define the text used for
//the split. The forward slash "\" is a special
//character and must be escaped. Some look and feels,
//such as Microsoft Windows, use the forward slash to
//delimit the path.
if ("\\".equals(fileSeparator)) {
fileSeparator = "\\\\";
}
init();
}
public JTextArea addTab(String filename) {
if (noFiles) {
tabbedPanel.remove(emptyFilePanel);
tabbedPanel.add(tabbedPane, BorderLayout.CENTER);
noFiles = false;
}
String[] str = filename.split(fileSeparator);
return makeTextPanel(str[str.length - 1], filename);
}
//Remove all tabs and their components, then put the default
//file area back.
public void clearAll() {
if (noFiles == false) {
tabbedPane.removeAll();
tabbedPanel.remove(tabbedPane);
}
init();
}
private void init() {
String defaultText = "Select one or more files from the file chooser and drop here...";
noFiles = true;
if (emptyFilePanel == null) {
emptyFileArea = new JTextArea(20, 15);
emptyFileArea.setEditable(false);
emptyFileArea.setDragEnabled(true);
emptyFileArea.setTransferHandler(transferHandler);
emptyFileArea.setMargin(new Insets(5, 5, 5, 5));
JScrollPane fileScrollPane = new JScrollPane(emptyFileArea);
emptyFilePanel = new JPanel(new BorderLayout(), false);
emptyFilePanel.add(fileScrollPane, BorderLayout.CENTER);
}
tabbedPanel.add(emptyFilePanel, BorderLayout.CENTER);
tabbedPanel.repaint();
emptyFileArea.setText(defaultText);
}
protected JTextArea makeTextPanel(String name, String toolTip) {
JTextArea fileArea = new JTextArea(20, 15);
fileArea.setDragEnabled(true);
fileArea.setTransferHandler(transferHandler);
fileArea.setMargin(new Insets(5, 5, 5, 5));
JScrollPane fileScrollPane = new JScrollPane(fileArea);
tabbedPane.addTab(name, null, (Component) fileScrollPane, toolTip);
tabbedPane.setSelectedComponent((Component) fileScrollPane);
return fileArea;
}
}
/*
* FileAndTextTransferHandler.java is used by the 1.4 DragFileDemo.java example.
*/
class FileAndTextTransferHandler extends TransferHandler {
private DataFlavor fileFlavor, stringFlavor;
private TabbedPaneController tpc;
private JTextArea source;
private boolean shouldRemove;
protected String newline = "\n";
//Start and end position in the source text.
//We need this information when performing a MOVE
//in order to remove the dragged text from the source.
Position p0 = null, p1 = null;
FileAndTextTransferHandler(TabbedPaneController t) {
tpc = t;
fileFlavor = DataFlavor.javaFileListFlavor;
stringFlavor = DataFlavor.stringFlavor;
}
public boolean importData(JComponent c, Transferable t) {
JTextArea tc;
if (!canImport(c, t.getTransferDataFlavors())) {
return false;
}
//A real application would load the file in another
//thread in order to not block the UI. This step
//was omitted here to simplify the code.
try {
if (hasFileFlavor(t.getTransferDataFlavors())) {
String str = null;
java.util.List files = (java.util.List) t
.getTransferData(fileFlavor);
for (int i = 0; i < files.size(); i++) {
File file = (File) files.get(i);
//Tell the tabbedpane controller to add
//a new tab with the name of this file
//on the tab. The text area that will
//display the contents of the file is returned.
tc = tpc.addTab(file.toString());
BufferedReader in = null;
try {
in = new BufferedReader(new FileReader(file));
while ((str = in.readLine()) != null) {
tc.append(str + newline);
}
} catch (IOException ioe) {
System.out
.println("importData: Unable to read from file "
+ file.toString());
} finally {
if (in != null) {
try {
in.close();
} catch (IOException ioe) {
System.out
.println("importData: Unable to close file "
+ file.toString());
}
}
}
}
return true;
} else if (hasStringFlavor(t.getTransferDataFlavors())) {
tc = (JTextArea) c;
if (tc.equals(source)
&& (tc.getCaretPosition() >= p0.getOffset())
&& (tc.getCaretPosition() <= p1.getOffset())) {
shouldRemove = false;
return true;
}
String str = (String) t.getTransferData(stringFlavor);
tc.replaceSelection(str);
return true;
}
} catch (UnsupportedFlavorException ufe) {
System.out.println("importData: unsupported data flavor");
} catch (IOException ieo) {
System.out.println("importData: I/O exception");
}
return false;
}
protected Transferable createTransferable(JComponent c) {
source = (JTextArea) c;
int start = source.getSelectionStart();
int end = source.getSelectionEnd();
Document doc = source.getDocument();
if (start == end) {
return null;
}
try {
p0 = doc.createPosition(start);
p1 = doc.createPosition(end);
} catch (BadLocationException e) {
System.out
.println("Can't create position - unable to remove text from source.");
}
shouldRemove = true;
String data = source.getSelectedText();
return new StringSelection(data);
}
public int getSourceActions(JComponent c) {
return COPY_OR_MOVE;
}
//Remove the old text if the action is a MOVE.
//However, we do not allow dropping on top of the selected text,
//so in that case do nothing.
protected void exportDone(JComponent c, Transferable data, int action) {
if (shouldRemove && (action == MOVE)) {
if ((p0 != null) && (p1 != null)
&& (p0.getOffset() != p1.getOffset())) {
try {
JTextComponent tc = (JTextComponent) c;
tc.getDocument().remove(p0.getOffset(),
p1.getOffset() - p0.getOffset());
} catch (BadLocationException e) {
System.out.println("Can't remove text from source.");
}
}
}
source = null;
}
public boolean canImport(JComponent c, DataFlavor[] flavors) {
if (hasFileFlavor(flavors)) {
return true;
}
if (hasStringFlavor(flavors)) {
return true;
}
return false;
}
private boolean hasFileFlavor(DataFlavor[] flavors) {
for (int i = 0; i < flavors.length; i++) {
if (fileFlavor.equals(flavors[i])) {
return true;
}
}
return false;
}
private boolean hasStringFlavor(DataFlavor[] flavors) {
for (int i = 0; i < flavors.length; i++) {
if (stringFlavor.equals(flavors[i])) {
return true;
}
}
return false;
}
}
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