Leap Motion problems with Swing?

Question

I'm starting to toy a little with the Leap Motion Controller and made a small GUI in Swing. That means it's just a Frame with a Label on it which should show a text of what the Leap Motion sees. Unfortunately my programm simply breaks down after two seconds. I have no Exceptions or something like that. Here's my code:

public class GUI extends JFrame{
private static final long serialVersionUID = 6411499808530678723L;

public JLabel label;

public GUI(){
    this.setDefaultCloseOperation(EXIT_ON_CLOSE);
    this.setSize(300, 200);
    this.label = new JLabel("Waiting for Gestures");
    this.add(label);

    setVisible(true);
}

public class LeapListener extends Listener{
    JLabel label;

    LeapListener(JLabel label){
        this.label = label;
    }

    @Override
    public void onInit(Controller controller){

    }

    @Override
    public void onExit(Controller controller){

    }

    @Override
    public void onConnect(Controller controller){
        System.out.println("bin da");
        controller.enableGesture(Gesture.Type.TYPE_CIRCLE);
        controller.enableGesture(Gesture.Type.TYPE_KEY_TAP);
        controller.enableGesture(Gesture.Type.TYPE_SCREEN_TAP);
        controller.enableGesture(Gesture.Type.TYPE_SWIPE);
    }

    @Override
    public void onDisconnect(Controller controller){

    }

    @Override
    public void onFrame(Controller controller){
        Frame frame = controller.frame();

        GestureList glist = frame.gestures();

        for (int i = 0; i < glist.count(); i++){
            Gesture g = glist.get(i);

            switch (g.type()){
            case TYPE_CIRCLE:
                CircleGesture circle = new CircleGesture(g);
                this.label.setText("Mach mal nen Kreis!");
            case TYPE_KEY_TAP:
                KeyTapGesture key = new KeyTapGesture(g);
                this.label.setText("Schreiben?");
            case TYPE_SCREEN_TAP:
                ScreenTapGesture screen = new ScreenTapGesture(g);
                this.label.setText("Klicken?");
            case TYPE_SWIPE:
                SwipeGesture swipe = new SwipeGesture(g);
                this.label.setText("Da wurde gewischt!");
            default:
                System.out.println("nothing!");
            break;
            }
        }
    }
}

public static void main(String[] args) {
    GUI gui = new GUI();
    LeapListener listener;
    listener = gui.new LeapListener(gui.label);
    Controller controller = new Controller();
    controller.addListener(listener);

}

}

I have no idea what I've done wrong. The Windows-Error-Message says that the Java Platform SE binary is down (javaw.exe). Errormodule: Leap.dll Is it a mistake that I've made or is my whole setup f@*ked up?

Where do you actually add your `LeapListener`? What do you mean by "simply breaks"? — Josh M, Sep 12 '13 at 12:51
The LeapListener is added in the very last line (controller.addListener(listener);) By "simply breaks" I mean that I don't get any java exceptions. The program simply crashes with a Windows-Error. — Raistlin, Sep 12 '13 at 12:56

score 0 · Answer 1 · answered Sep 12 '13 at 13:20

Ok, I found a solution by myself but unfortunately I can't explain it.
I have to create the Controller Object in the class declaration, not in the main-method. Then I have to add the listener to the controller in the constructor of my GUI, like that:

public class GUI extends JFrame{
private static final long serialVersionUID = 6411499808530678723L;

public JLabel label;
public Controller c = new Controller();
public LeapListener listener;

public GUI(){
    this.setDefaultCloseOperation(EXIT_ON_CLOSE);
    this.setSize(300, 200);
    this.label = new JLabel("Waiting for Gestures");
    this.add(label);
    listener = new LeapListener(this.label);
    c.addListener(listener);
    setVisible(true);
}
    ...
}

So, I'm happy that I got it to work but maybe somebody is interested in the problem and may find a reason for the error I've had.

Once your main() function exits, any local variables, including the Controller object in your first version, go out of scope and are eligible for garbage collection. — Charles Ward, Sep 17 '13 at 23:03

Leap Motion problems with Swing?

1 Answers1