mouseMoved is never called

Newbie & Debugging Questions
#1

Hi everyone.
The problem is simple: the mouseMoved event is never called.
Let’s see the code.

public class Window extends javax.swing.JFrame {

    public Window() {
        initComponents();
        setVisible(true);
        setResizable(false);
        jPanel1.setVisible(true);
        jPanel1.setBounds(0,0,300,300);
        
        Game g = new Game();
        jPanel1.add(g);
    }

public Game()
    {
        setVisible(true);
        setBounds(0,0,300,300);
        map = new Map();
        drawer = new Drawer(map);
        listener = new Listener(map);
        t = new Thread(this);
        
        this.add(drawer);
        addMouseListener(listener);
        t.start();
    }

public class Listener extends MouseAdapter{

    int mouseX, mouseY;
    Map map;
    public Listener(Map copyMap)
    {
        mouseX = 0;
        mouseY = 0;
        map = copyMap;   
    }
    
    @Override
    public synchronized void mouseMoved(MouseEvent evt)
    {
        GetMouseCords(evt);
        ShouldMoveView();
        System.out.println("fuck");
    }

Got any tips? thanks!

#2 
public Game()
    {
        setVisible(true);
        setBounds(0,0,300,300);
        map = new Map();
        drawer = new Drawer(map);
        listener = new Listener(map);
        t = new Thread(this);
        
        this.add(drawer);
        addMouseListener(listener);
+       addMouseMotionListener(listener);
        t.start();
    }
#3

Gosh, that’s a fast reply!!
Already tried that, but didn’t work.

Could be it that the Listener never obtains focus? Will help if I tell you that the game calls repaints functions?

#4

add this in your jpanel

@Override
public void addNotify() {
setFocusable(true);
this.requestFocus();
}

that should work

#5

It might not have worked, but it is mandatory for it to work, once you solved the other issues.

#6

I’m surprised! it didn’t work either!
I also found that if I put breakpoint on listener and I go into debug mode… the code Works good.

Any other ideas?

thanks.

#7

So, you’re saying that [icode]System.out.println(“f**k”);[/icode] is executed, but nothing appears in the console?

  1. Does anything appear in the console? (put some prints in the Game-constructor)
  2. If so, maybe some other part of your code actually closes the System.out.

Sometimes people use a typical method that copies an InputStream into and OutputStream, and closing the streams to finalize the copy. If you were to use such a method on System.out, it will effectively mute it, from then on.

#8

If nothing appears in the console then how do you know it executed?

Im guessing its because youre running an old classfile. Try a clean and build, in NetBeans or a Clean and Rebuild All in Eclipse.

#9

Also remember that Java2D/Swing is not thread safe.

Does the Game-constuctor get executed on the Event Dispatch Thread? If not, that may very well cause all kinds of trouble.

Your usage of the synchronized keyword there is a sure giveaway of concurrency problems - please read into how Java AWT/Swing uses the E.D.T., and how you interact with it. You basically have to ensure that all your GUI manipulating code runs on that very thread, not your own.

#10

To add to what Riven said, make sure you create your entire GUI/window thing in a SwingUtilities.invokeLater or invokeAndWait runnable.

#11

Ok, now it Works. I added Agros’ code wrong before.
Now I’m having another problem (I always have problems with two things: eventListeners and Backbuffers)

I’m implementing backbuffer on a Drawer, like this:

public class Drawer extends Applet {
    
    Image backbuffer;
    Graphics graphics;
    Map map;
    
    boolean firstTime;
    
    public Drawer(Map mapCopy)
    {
        setVisible(true);
        setBounds(0,0,300,300);
        map = mapCopy;
        firstTime = true;
    }

    public void Draw()
    {
        //draw lots of things into graphics        
        repaint();
        
    }
    
    public void update( Graphics g ) 
    {
        g.drawImage( backbuffer, 0, 0, this );
    }

    public void paint( Graphics g ) 
    {  
       if(firstTime)
       {
            backbuffer = createImage(getSize().width,getSize().height);
            graphics = backbuffer.getGraphics();
       }
       update( g );
    }
}

I’ve read tons of examples of how to implement it, but all sites use different methods, and I just tried to use the most convenient.
The problem is simple: when Draw() method is called, graphics returns null, and doesn’t let me draw anything into it.

Thanks.

#12

I dont know what youre trying to accomplish, but you have an Applet in a JPanel in a JPanel in a JFrame…

Not sure if thats nesessary, I wrote a piece of code that renders fine, detects mouse movements and everything, feel free to use it



import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
/**
 *
 * @author David
 */
public class Lol {

    static class Window extends JFrame {

        public Window() {
            setVisible(true);
            setResizable(false);
            Game g = new Game();
            add(g);
            
            pack();
            
            g.requestFocusInWindow();
        }
    }

    static class Game extends JPanel implements Runnable {
        int i = 0;

        public Game() {
            setVisible(true);
            setPreferredSize(new Dimension(300, 300));
            Listener listener = new Listener();
            Thread t = new Thread(this);
            addMouseMotionListener(listener);
            addMouseListener(listener);
            t.start();
        }

        public void run() {
            while (true) {
                repaint();
                try {
                    Thread.sleep(10);
                } catch (InterruptedException ex) {
                    Logger.getLogger(Lol.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
        }
        
        @Override
        public void paint(Graphics g) {
            super.paint(g);
            g.drawString("Count:"+(i++), 40, 40);
        }
    }

    static class Listener extends MouseAdapter {

        int mouseX, mouseY;

        public Listener() {
            mouseX = 0;
            mouseY = 0;
        }

        @Override
        public void mouseMoved(MouseEvent evt) {
            System.out.println("f**k");
        }
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            public void run() {
                new Window().setVisible(true);
            }
        });
    }

}

If you want to use proper active-rendering, you’ll need to use BufferStrategy.

#13

Ok, I’ve taken your advice into having the Game extends from JPanel. But what if I want the paint methods to be in another class? that’s why I created a Drawer. what do you recommend here? Drawer should extend from what??

I’m implementing BufferStrategy, as son as I have it working I’m going to post here with results.

thanks.

#14

I’m starting to think you’re just a troll.

Sorry for the off topic comment.

#15

It would be more constructive if you posted why JFrame is “eww”…

#16

You can just make Drawer extend Object, and have a method like doRender(Graphics2D) and call that from paint.

#17

Ok, so I basically redesigned the hierarchy of classes.
Now is like so:

Game -> Drawer (JFrame) -> Listener

Game is a class, which instantiates a Drawer (JFrame), and this contains the Listener.
Also, I’m implementing BufferStrategy on Drawer.

Now it Works perfectly, using the same help you gave me =).

Thanks!