Mouse cursor detecting Java

Question

I would want my mouse positions to get detected for dragging object. I want the object will be able to be dragged only when the mouse cursor is pointing at the object

I can drag the object with .setObjPos(e.getX(),e.getY()). But the object keep jump to wherever the mouse cursor is. I want the object can only be dragged when the mouse cursor pointing at the object.

Answer 1

You can achieve this quite easily by implementing a custom MouseListener:

public final class DragListener extends MouseInputAdapter {

    private Point location;
    private MouseEvent pressed;


    public DragListener() {
    }


    public void mousePressed(final MouseEvent me) {
        pressed = me;
    }


    public void mouseDragged(final MouseEvent me) {
        if (pressed == null) {
            return;
        }
        Component component = me.getComponent();
        location = component.getLocation(location);
        int x = location.x - pressed.getX() + me.getX();
        int y = location.y - pressed.getY() + me.getY();
        component.setLocation(x, y);
    }
}

You can then add this custom Listener to any component like so:

DragListener dragListener = new DragListener();
frame.addMouseListener(dragListener);
frame.addMouseMotionListener(dragListener);

This will detect the MouseEvents on the component it is set to and only drag the component while the left mouse button is being pressed.