Question

I’m working on a GUI for a card game and am using the ACM’s student graphics library for the sake of familiarity. I have written a program that draws my solitaire game to the screen, and am having trouble making it interactive.

Background:

There are a lot of classes here, and I’ll do my best to describe them each.

• Top level JFrame containing the application.
  • GCanvas (that holds all the graphics objects)
    • SolitaireGameControl (GCompound holding all the other GCompounds making up the solitaire game)
      • Array of PileViews, a pile of cards (GCompound consisting of an array of Cards)
        • Cards (GCompound consisting of rectangles and labels)

(GCompound: a collection of graphics objects treated as one object. (If car was a GCompound, it would have GOval[] wheels, GRect body and so when I add it to the canvas, it displays as one object))

A card as seen from the top-level class would look like a bit like this: jFrame.gCanvas.solitaireGameControl.pileViews[pile number].cardView

What I’ve been trying to do is add a MouseListener to every single card, so that when a card is clicked and a MouseEvent is fired, MouseEvent e.getSource() = the card that was clicked.

Here’s how it looks now:

public SolitaireGameControl(SolitaireGame game) {
    this.game = game; // Model of the game.
    this.pileViews = PileView.getPileViews(game.drawPiles); // ArrayList of PileViews (the pile of cards)

    for(PileView pv : pileViews) {
        for(CardView cv : pv.cardViews) {
            cv.addMouseListener(this); // add a mouseListener to the card
        }
    }

    this.addMouseListener(this); // if I don't include this, nothing happens when I click anything. If I do include this, this whole object is the source.
}

@Override
public void mouseClicked(MouseEvent e) {
    System.out.println(e.getSource()); // should return the card I clicked.
}

When I run this program, the source of every event is SolitaireGameControl, granted I leave in the this.addMouseListener(this);. If I take out this statement, nothing is printed at all, leading me to believe that the mouseListeners I have added are only working one level deep. (The first GCompound on the canvas, not the GCompounds inside it.)

Therefore, my question is as follows: Is there a way to get a MouseListener for a GCompound inside of a GCompound inside of a GCompound, and have MouseEvent’s getSource to correctly identify the card? If not, is there a way to restructure my program to make it work as intended? (I know I should really be using a better graphics library for starters.)

Answer 1

That would make sense. From my experience, if I put some components inside a top-level container, the container is the one that receives input events.

Have you tried an approach where you do something like:

/* This is the mouse listener for the top-level container. */
@Override
public void mouseClicked(MouseEvent e) {
    for(PileView pv : pileViews) {
        for(CardView cv : pv.cardViews) {
            if(cv.getBounds().contains(e.getPoint())) {
                cv.dispatchEvent(e);
            }
        }
    }
}

… and then handle mouse clicks on a ‘CardView’ level normally.

When the top-level container receives a mouse event, it checks if the mouse interacted with a card based on the location of the event (if the card’s area contains the point). If it did, it passes down the mouse event to the card’s mouse listener.

I’m assuming that the elements near the beginning of ‘pv.cardViews’ are the cards that are more to the front.