CODEWITHSUNDEEP
javaswingkeylistener
Sumtinlazy
Sumtinlazy

Reputation: 347

Binding Keys to Move an Image

I am working on a game for a school project and as one step I have to bind keys to the image that will add/subtract from the x-y axis. However the way I have done it does not seem to work and instead of adding by a small amount increases the x/y by a lot and teleports the image away off of the screen.

The KeyListener code

public void keyPressed(KeyEvent e) {

    if (e.getKeyCode() == 87) {
        up = true ;
        if (e.getKeyCode() == 65) {
            left = true ; 
        }
        if (e.getKeyCode() == 68) {
            right = true ;
        }
        if (e.getKeyCode() == 83) {
            down = true ;
        }
    }

}

@Override
public void keyReleased(KeyEvent e) {

    if (e.getKeyCode() == 87) {
        up = false ;
    }
    if (e.getKeyCode() == 65) {
        left = false; 
    }
    if (e.getKeyCode() == 68) {
        right = false ;
    }
    if (e.getKeyCode() == 83) {
        down = false ;
    }

}

The Game Loop

public void run() {

    while(running) {

        //Player movement
        if (up) {
            y++ ;
        }
        if (left) {
            x-- ;
        }
        if (right) {
            x++;
        }
        if (down) {
            y-- ;
        }
        //Player movement

    }
}

Graphical Loop

protected void paintComponent(Graphics g) {
    super.paintComponent(g);
    //Graphical loop start
    g.drawImage(Player, x, y, null) ;       

    //Graphical loop end
    repaint();

Upvotes: 1

Views: 74

Answers (2)

camickr
camickr

Reputation: 324108

Doesn't answer your question but:

if (e.getKeyCode() == 87)

Don't use "magic numbers". People don't know what "87" means. Use the field names provided by the API:

if (e.getKeyCode() == KeyEvent.VK_UP)

Also, in your paintComponent() method you have:

//Graphical loop end
repaint();

Don't ever invoke repaint() within a painting method. This will cause an infinite loop. Get rid of that code.

Upvotes: 3

user4668606
user4668606

Reputation:

The code works just the way it's supposed to. You only forgot one thing: the while-loop for moving the image is running a lot faster than you seem to expect it to run. Simply insert a Thread.sleep(someDelay) to make the loop run slower and the image should move with a more "userfriendly" speed.

Upvotes: 3

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