Overwritable TextField
/*
Core SWING Advanced Programming
By Kim Topley
ISBN: 0 13 083292 8
Publisher: Prentice Hall
*/
import java.awt.Graphics;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.FocusEvent;
import java.awt.event.KeyEvent;
import javax.swing.Action;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.KeyStroke;
import javax.swing.UIManager;
import javax.swing.plaf.TextUI;
import javax.swing.text.BadLocationException;
import javax.swing.text.Caret;
import javax.swing.text.DefaultCaret;
import javax.swing.text.Document;
import javax.swing.text.JTextComponent;
import javax.swing.text.Keymap;
import javax.swing.text.TextAction;
public class OverwritableTextField extends JTextField {
public OverwritableTextField() {
this(null, null, 0);
}
public OverwritableTextField(String text) {
this(null, text, 0);
}
public OverwritableTextField(int columns) {
this(null, null, columns);
}
public OverwritableTextField(String text, int columns) {
this(null, text, columns);
}
public OverwritableTextField(Document doc, String text, int columns) {
super(doc, text, columns);
overwriteCaret = new OverwriteCaret();
super.setCaret(overwriting ? overwriteCaret : insertCaret);
}
public void setKeymap(Keymap map) {
if (map == null) {
super.setKeymap(null);
sharedKeymap = null;
return;
}
if (getKeymap() == null) {
if (sharedKeymap == null) {
// Switch keymaps. Add extra bindings.
removeKeymap(keymapName);
sharedKeymap = addKeymap(keymapName, map);
loadKeymap(sharedKeymap, bindings, defaultActions);
}
map = sharedKeymap;
}
super.setKeymap(map);
}
public void replaceSelection(String content) {
Document doc = getDocument();
if (doc != null) {
// If we are not overwriting, just do the
// usual insert. Also, if there is a selection,
// just overwrite that (and that only).
if (overwriting == true && getSelectionStart() == getSelectionEnd()) {
// Overwrite and no selection. Remove
// the stretch that we will overwrite,
// then use the usual code to insert the
// new text.
int insertPosition = getCaretPosition();
int overwriteLength = doc.getLength() - insertPosition;
int length = content.length();
if (overwriteLength > length) {
overwriteLength = length;
}
// Remove the range being overwritten
try {
doc.remove(insertPosition, overwriteLength);
} catch (BadLocationException e) {
// Won't happen
}
}
}
super.replaceSelection(content);
}
// Change the global overwriting mode
public static void setOverwriting(boolean overwriting) {
OverwritableTextField.overwriting = overwriting;
}
public static boolean isOverwriting() {
return overwriting;
}
// Configuration of the insert caret
public void setCaret(Caret caret) {
insertCaret = caret;
}
// Allow configuration of a new
// overwrite caret.
public void setOverwriteCaret(Caret caret) {
overwriteCaret = caret;
}
public Caret getOverwriteCaret() {
return overwriteCaret;
}
// Caret switching
public void processFocusEvent(FocusEvent evt) {
if (evt.getID() == FocusEvent.FOCUS_GAINED) {
selectCaret();
}
super.processFocusEvent(evt);
}
protected void selectCaret() {
// Select the appropriate caret for the
// current overwrite mode.
Caret newCaret = overwriting ? overwriteCaret : insertCaret;
if (newCaret != getCaret()) {
Caret caret = getCaret();
int mark = caret.getMark();
int dot = caret.getDot();
caret.setVisible(false);
super.setCaret(newCaret);
newCaret.setDot(mark);
newCaret.moveDot(dot);
newCaret.setVisible(true);
}
}
protected Caret overwriteCaret;
protected Caret insertCaret;
protected static boolean overwriting = true;
public static final String toggleOverwriteAction = "toggle-overwrite";
protected static Keymap sharedKeymap;
protected static final String keymapName = "OverwriteMap";
protected static final Action[] defaultActions = { new ToggleOverwriteAction() };
protected static JTextComponent.KeyBinding[] bindings = { new JTextComponent.KeyBinding(
KeyStroke.getKeyStroke(KeyEvent.VK_INSERT, 0),
toggleOverwriteAction) };
// Insert/overwrite toggling action
public static class ToggleOverwriteAction extends TextAction {
ToggleOverwriteAction() {
super(toggleOverwriteAction);
}
public void actionPerformed(ActionEvent evt) {
OverwritableTextField.setOverwriting(!OverwritableTextField
.isOverwriting());
JTextComponent target = getFocusedComponent();
if (target instanceof OverwritableTextField) {
OverwritableTextField field = (OverwritableTextField) target;
field.selectCaret();
}
}
}
public static void main(String[] args) {
try {
UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
} catch (Exception evt) {}
JFrame f = new JFrame("Overwrite test");
OverwritableTextField tf = new OverwritableTextField(20);
f.getContentPane().add(tf, "North");
tf = new OverwritableTextField(20);
f.getContentPane().add(tf, "South");
f.pack();
f.setVisible(true);
}
}
class OverwriteCaret extends DefaultCaret {
protected synchronized void damage(Rectangle r) {
if (r != null) {
try {
JTextComponent comp = getComponent();
TextUI mapper = comp.getUI();
Rectangle r2 = mapper.modelToView(comp, getDot() + 1);
int width = r2.x - r.x;
if (width == 0) {
width = MIN_WIDTH;
}
comp.repaint(r.x, r.y, width, r.height);
// Swing 1.1 beta 2 compat
this.x = r.x;
this.y = r.y;
this.width = width;
this.height = r.height;
} catch (BadLocationException e) {
}
}
}
public void paint(Graphics g) {
if (isVisible()) {
try {
JTextComponent comp = getComponent();
TextUI mapper = comp.getUI();
Rectangle r1 = mapper.modelToView(comp, getDot());
Rectangle r2 = mapper.modelToView(comp, getDot() + 1);
g = g.create();
g.setColor(comp.getForeground());
g.setXORMode(comp.getBackground());
int width = r2.x - r1.x;
if (width == 0) {
width = MIN_WIDTH;
}
g.fillRect(r1.x, r1.y, width, r1.height);
g.dispose();
} catch (BadLocationException e) {
}
}
}
protected static final int MIN_WIDTH = 8;
}
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