Can't get java to work quite right (developing)

[hanes]

Hi, Im making an quick program in java. It all seems to work, but the applets never get keyEvents.... For example, the code below is an applet that when ran, should move a red dot left or right depending on key presses. But for some reason in linux, NO KEY EVENTS for the applet at all. In windoes or mac it works fine. I have tested this with konqueror, appletviewer and firefox.. no dice.

 

Anyone know whats going on?

 

example code

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;

public class Bubbles extends JApplet implements KeyListener
{

int msg = 0;

public void init()
{
msg = 10;
addKeyListener(this);
}
//this function happens when someone hits a button
public void keyPressed(KeyEvent e)
{
System.out.println("SFDF");
msg = e.getKeyCode();
repaint();
}

public void keyReleased(KeyEvent e)
{
System.out.println("SFDF");
repaint();
}
public void keyTyped(KeyEvent e)
{
System.out.println("SFDF");
msg = e.getKeyCode();
repaint();
}

public void paint(Graphics g)
{
g.drawString("code = " + msg, 20,20);

}
}

Edited November 10, 2006 by hanes

[neddie]

Have you tried clicking on the applet to make sure it's got keyboard focus from the browser?

[hanes]

I teach Java, and my students ALWAYS bug me about this, and, they never click on the browser... so its a good tip.

 

BUT

 

Yeah, I have clicked and clicked and clicked... i dont get it

[neddie]

Seems like the JApplet is unable to get the keyboard focus - I'm not quite sure why but even a setFocusable(true) doesn't fix it. Of course, usually there's a bit more in the applet so it's not usually a problem.

 

Workaround fix: use a Canvas instead:

import java.awt.Canvas;
import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JApplet;

public class Testclick extends JApplet implements KeyListener
{

int msg = 0;
Canvas canvas = null;

public void init()
{
	msg = 1;
	canvas = new Canvas() {
		public void paint(Graphics g)
		{
			g.drawString("code = " + msg, 20,20);
		}
	};
	canvas.addKeyListener(this);
	getContentPane().add(canvas);
}

//	this function happens when someone hits a button
public void keyPressed(KeyEvent e)
{
	System.out.println("key press: " + e.getKeyCode());
	msg = e.getKeyCode();
	canvas.repaint();
}

public void keyReleased(KeyEvent e)
{
	System.out.println("key release");
}
public void keyTyped(KeyEvent e)
{
	System.out.println("key typed: " + e.getKeyChar());
}
}

Does that work?

[hanes]

Yes it works. Thanks a lot.

 

It also really pisses me off. How many years has sun had to get this thing right? I remember how excited I was when I was learning Java, thinking that I was learning a professional and well thought out language. Now, I see the bug reports grow, the lag persist (remember when Sun was touting that Java was fast?!)

 

I gotta find another language to teach :)

 

Anyways, thanks for the help.

[neddie]