Re: Checking if certain k
To: comp.lang.java.gui
Kamil.Szot@gmail.com wrote:
In Photoshop when you hold spacebar you can drag the zoomed in document
with left mouse button.
I want to achieve same effect in Swing java app.
I need to test in mouse event whether spacebar is pressed. I know how
to do it for Alt, Shift and similar special keys, but how to do it for
spacebar ?
Hi Kamil,
I think you are going to have to keep track of the state of the
spacebar yourself. Try this sample code below and see if it helps you
out.
Cheers,
Dan Andrews
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Ansir Development Limited http://www.ansir.ca
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import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class TestFrame extends JFrame {
TestFrame() {
JPanel panel = new JPanel();
panel.setPreferredSize(new Dimension(100, 100));
/*
* Not really much point in the panel being focusable
* but for the example we need key events.
*/
panel.setFocusable(true);
SpecialListener listener = new SpecialListener();
panel.addMouseListener(listener);
panel.addMouseMotionListener(listener);
panel.addKeyListener(listener);
getContentPane().add(panel, BorderLayout.CENTER);
}
private void processSpaceBarDrag(MouseEvent e) {
System.out.println("Processing spaceBar drag");
}
private void completeSpaceBarDrag() {
System.out.println("Completing spaceBar drag");
}
private class SpecialListener extends MouseAdapter implements
MouseMotionListener, KeyListener {
private boolean spaceBarPressed = false;
private boolean spaceBarDragging = false;
public void mouseReleased(MouseEvent e) {
if (spaceBarDragging) {
spaceBarDragging = false;
completeSpaceBarDrag();
}
}
public void mouseDragged(MouseEvent e) {
if (spaceBarPressed) {
spaceBarDragging = true;
processSpaceBarDrag(e);
}
}
public void mouseMoved(MouseEvent e) {
}
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_SPACE) {
spaceBarPressed = true;
}
}
public void keyReleased(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_SPACE) {
spaceBarPressed = false;
if (spaceBarDragging) {
spaceBarDragging = false;
completeSpaceBarDrag();
}
}
}
public void keyTyped(KeyEvent e) {
}
}
public static void main(String[] args) {
JFrame frame = new TestFrame();
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
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