How do I properly apply your event system for my component?

[nightm4re94]

^{This post has been migrated automatically from the old LITIENGINE forum (2018 - 2022).
Posted: 2019-12-10 12:13:50
User: KvaGram [] (age: 1068 days 🔥; posts: 52)}
I wrote this scroll-component for my UI elements. It's crude, and I just bypass your mouse events in favor of my own. Yet, it works. And so I ask, is there a better way?
public enum Axis2D {vertical, horizontal} interface ScrollbarListener{void onScrollUpdate(Axis2D axis, double value);} public class Scrollbar extends GuiComponent { private final Axis2D axis; private Dimension viewArea; private final Dimension area; private double scroll; private ArrayList<ScrollbarListener> listeners; public Scrollbar(double x, double y, double width, double height, Axis2D axis, Dimension area, Dimension viewArea) { super(x, y, width, height); this.area = area; this.axis = axis; this.viewArea = viewArea; listeners = new ArrayList<>(); } @Override public void mouseDragged(final MouseEvent e) { //confirm the mouse is over the scrollbar. if(isSuspended() || !this.getBoundingBox().contains(e.getX(), e.getY())) { super.mouseDragged(e); return; } scrollUpdate(e); } @Override public void mousePressed(final MouseEvent e) { //confirm the mouse is over the scrollbar. if(isSuspended() || !this.getBoundingBox().contains(e.getX(), e.getY())) { super.mouseDragged(e); return; } scrollUpdate(e); } private int scrollable() { if(axis == Axis2D.horizontal) return area.width - viewArea.width; else return area.height - viewArea.height; } public void scrollUpdate(final MouseEvent e) { if(axis == Axis2D.horizontal) scroll = ((e.getX() - getX()) / getWidth()) * scrollable(); else //Axis2D.vertical scroll = ((e.getY() - getY()) / getHeight()) * scrollable(); if(scroll < 0) scroll = 0; else if (scroll > scrollable()) scroll = scrollable(); //runs scrollupdate on all listeners for (ScrollbarListener evt : listeners) { evt.onScrollUpdate(axis, scroll); } } public void addScrollListener(ScrollbarListener listener) { listeners.add(listener); } public boolean removeScrollListener(ScrollbarListener listener) { return listeners.remove(listener); } public boolean tooSmall(){ return scrollable() <= 0; } @Override public void render(Graphics2D g) { super.render(g); if(tooSmall()) return; double x = getX(); double y = getY(); RoundRectangle2D bar = new RoundRectangle2D.Double(x, y, getWidth(), getHeight(), 10, 10); //offset x or y with the current scroll value if(axis == Axis2D.horizontal) x += getWidth() * (scroll / scrollable()); else y += getHeight() * (scroll / scrollable()); Rectangle.Double knob = new Rectangle.Double(x, y, getHeight(), getHeight()); g.setColor(Color.darkGray); g.fill(bar); g.setColor(Color.LIGHT_GRAY); g.fill(knob); } }