Drag Color TextField Demo
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*
* This software is provided "AS IS," without a warranty of any kind. ALL
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* ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
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/*
* DragColorTextFieldDemo.java is a 1.4 example that requires
* the following files:
* ColorTransferHandler.java
* ColorAndTextTransferHandler.java
*/
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.StringSelection;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.event.KeyEvent;
import java.io.IOException;
import javax.swing.BorderFactory;
import javax.swing.JCheckBox;
import javax.swing.JColorChooser;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.TransferHandler;
import javax.swing.text.BadLocationException;
import javax.swing.text.DefaultEditorKit;
import javax.swing.text.Document;
import javax.swing.text.JTextComponent;
import javax.swing.text.Position;
/**
* Example code that shows a text component that both accepts color (by changing
* its foreground) and also exports simple text.
*/
public class DragColorTextFieldDemo extends JPanel {
JCheckBox toggleForeground;
ColorAndTextTransferHandler colorHandler;
public DragColorTextFieldDemo() {
super(new BorderLayout());
JTextField textField;
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 ColorAndTextTransferHandler();
//Create some text fields.
JPanel buttonPanel = new JPanel(new GridLayout(3, 1));
textField = new JTextField("I can accept color/text and drag text.");
textField.setTransferHandler(colorHandler);
textField.setDragEnabled(true);
buttonPanel.add(textField);
textField = new JTextField("Me too!");
textField.setTransferHandler(colorHandler);
textField.setDragEnabled(true);
buttonPanel.add(textField);
textField = new JTextField("Me three!");
textField.setTransferHandler(colorHandler);
textField.setDragEnabled(true);
buttonPanel.add(textField);
add(buttonPanel, BorderLayout.CENTER);
}
//Create an Edit menu to support cut/copy/paste.
public JMenuBar createMenuBar() {
JMenuItem menuItem = null;
JMenuBar menuBar = new JMenuBar();
JMenu mainMenu = new JMenu("Edit");
mainMenu.setMnemonic(KeyEvent.VK_E);
menuItem = new JMenuItem(new DefaultEditorKit.CutAction());
menuItem.setText("Cut");
menuItem.setMnemonic(KeyEvent.VK_T);
mainMenu.add(menuItem);
menuItem = new JMenuItem(new DefaultEditorKit.CopyAction());
menuItem.setText("Copy");
menuItem.setMnemonic(KeyEvent.VK_C);
mainMenu.add(menuItem);
menuItem = new JMenuItem(new DefaultEditorKit.PasteAction());
menuItem.setText("Paste");
menuItem.setMnemonic(KeyEvent.VK_P);
mainMenu.add(menuItem);
menuBar.add(mainMenu);
return menuBar;
}
/**
* 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("DragColorTextFieldDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Create and set up the menu bar and content pane.
DragColorTextFieldDemo demo = new DragColorTextFieldDemo();
frame.setJMenuBar(demo.createMenuBar());
demo.setOpaque(true); //content panes must be opaque
frame.setContentPane(demo);
//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();
}
});
}
}
/*
* ColorAndTextTransferHandler.java is used by the 1.4 DragColorDemo.java
* example.
*/
/**
* An implementation of TransferHandler that adds support for the import of
* color and the import and export of text. Dropping a color on a component
* having this TransferHandler changes the foreground of the component to the
* imported color.
*/
class ColorAndTextTransferHandler extends ColorTransferHandler {
private DataFlavor stringFlavor = DataFlavor.stringFlavor;
private JTextComponent source;
private boolean shouldRemove;
//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;
//Get the flavors from the Transferable.
//Is there a color flavor? If so, set the foreground color.
//Is there a string flavor? If so, set the text property.
public boolean importData(JComponent c, Transferable t) {
JTextComponent tc = (JTextComponent) c;
if (!canImport(c, t.getTransferDataFlavors())) {
return false;
}
if (tc.equals(source) && (tc.getCaretPosition() >= p0.getOffset())
&& (tc.getCaretPosition() <= p1.getOffset())) {
shouldRemove = false;
return true;
}
if (hasStringFlavor(t.getTransferDataFlavors())) {
try {
String str = (String) t.getTransferData(stringFlavor);
tc.replaceSelection(str);
return true;
} catch (UnsupportedFlavorException ufe) {
System.out.println("importData: unsupported data flavor");
} catch (IOException ioe) {
System.out.println("importData: I/O exception");
}
}
//The ColorTransferHandler superclass handles color.
return super.importData(c, t);
}
//Create a Transferable implementation that contains the
//selected text.
protected Transferable createTransferable(JComponent c) {
source = (JTextComponent) 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;
}
/**
* Does flavors contain a color or string Transferable?
*/
public boolean canImport(JComponent c, DataFlavor[] flavors) {
if (hasStringFlavor(flavors)) {
return true;
}
return super.canImport(c, flavors);
}
/**
* Does the flavor list have a string flavor?
*/
protected boolean hasStringFlavor(DataFlavor[] flavors) {
for (int i = 0; i < flavors.length; i++) {
if (stringFlavor.equals(flavors[i])) {
return true;
}
}
return false;
}
}
/*
* 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;
}
}
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