Changing images in a image array with keypresses

[Nonoon]

Hello

I have been trying to change the images within a image array with the up/down arrow keypresses. Despite pressing the keys the images do not change.

import java.applet.Applet;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.image.BufferedImage;
import java.net.URL;


public class Main extends Applet implements Runnable, KeyListener{


	 Image[] MenuImages = new Image[4];
	 int frame = 0;
	 boolean [] keys = new boolean[500];
	 boolean running = false;


	public void init () {
		{
			System.out.println("Applet::init() called"); 
			try {
				MenuImages[0] = loadImage("res/MainMenu.png");
				MenuImages[1] = loadImage("res/ImageOne.png");
				MenuImages[2] = loadImage("res/ImageTwo.png");
				MenuImages[3] = loadImage("res/ImageThree.png");
			} catch(Exception ex) {
			}
			
		}
	}
	
	public void start() 
	{
		System.out.println("Applet::start() called");
		Thread th = new Thread(this); 
		addKeyListener(this);
	    running= true;
		th.start();
	}

	private Image loadImage( String filename )
	{
		Image img = null;
		URL url = this.getClass().getResource(filename);
		System.out.println(url.toString());
		img = Toolkit.getDefaultToolkit().getImage(url);
		return img;
	}
	
    public void paint(Graphics g) {
        g.drawImage(MenuImages[frame], 0, 0, this);
    }
	
	private void gameUpdate()
	{
	if(keys[KeyEvent.VK_UP]){
	frame++;
	System.out.println("Applet::keypress() called");
		
		//keys[KeyEvent.VK_UP] = false;
	}
	if(keys[KeyEvent.VK_DOWN]){
		frame--;
        System.out.println("Applet::keypress() called");
		
			
	//	keys[KeyEvent.VK_DOWN] = false;
	}
	
	}

	@Override
	public void keyTyped(KeyEvent e) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void keyPressed(KeyEvent e) {
		// TODO Auto-generated method stub
		keys[e.getKeyCode()] = true;	
	}

	@Override
	public void keyReleased(KeyEvent e) {
		// TODO Auto-generated method stub
		keys[e.getKeyCode()] = false;			
	}

	@Override
	public void run() {
		// TODO Auto-generated method stub
		{

			System.out.println("Applet::run() called");
			while(running)
			{
				gameUpdate();
				repaint();  

				try
				{
					Thread.sleep(40);
				}
				catch(InterruptedException ex)
				{

				}
			}
		}
		
	}

}

The few System.out.println lines added to the keypresses do not come up at all even when the keys are pressed. Does anyone have any idea where I made a mistake in the code?

Thanks for the time and help!

[Shoss]

It seems to work fine for me, printlns show up and the images change. How are you running the applet?

[Norm]

Sounds like your component with the key listener does not have the focus.
Have you tried clicking on the applet before pressing the keys?

[Nonoon]

Sorry for the wait for this reply! After reading Shoss's reply I made a new project and just copy and pasted everything into it. Somehow started working then. I was running it the same before, as a java applet.

Sounds like your component with the key listener does not have the focus.
Have you tried clicking on the applet before pressing the keys?

This does happen now. Is it to be expected? Looking through tutorials they seem to just have it the same way as I do.

Thanks for the replies and help!

[Norm]

There are methods in the Component class you can call to request the focus.
Also you might read in the tutorial:
How to Use the Focus Subsystem (The Java™ Tutorials > Creating a GUI With JFC/Swing > Using Other Swing Features)

[DarrylBurke]

Better still, learn about and use key bindings instead.
How to Use Key Bindings (The Java™ Tutorials > Creating a GUI With JFC/Swing > Using Other Swing Features)

db

[Fubarable]

Better still, learn about and use key bindings instead.
How to Use Key Bindings (The Java™ Tutorials > Creating a GUI With JFC/Swing > Using Other Swing Features)

I'm a big fan of Key Bindings as you know, but I thought that it was Swing specific. Will it work for an AWT program? Thanks in advance.

/Pete