Game Builder Tutorial 2: Build a Blackjack Card Game (Duke Jack)

In Tutorial 1 Duke dashed for coffee with arcade physics. Now he sets the cup down for a calmer contest: Duke Jack , a game of blackjack. A card game has none of that arcade motion — cards sit on the felt and the rules decide who wins. This tutorial shows how the same Game Builder pattern (visual data + an onUpdate companion) handles a card game, where your code reads the cards and runs the table instead of simulating movement. We'll build a felt table, deal a real hand, and wire up the complete blackjack rules: hit, stand, the dealer's draw, and the win/lose decision. What is Codename One? Codename One is an open-source framework for building native iOS, Android, desktop, and web apps from a single Java or Kotlin codebase. Learn more at codenameone.com . If you haven't set up a project yet, the project setup in Tutorial 1 applies verbatim — only the mode changes (board mode isn't the default, so the -Dmode=board flag is required here): mvn cn1:create-game-scene -DclassName = com.example.dukejack.DukeJack -Dmode = board mvn cn1:gamebuilder Why board mode for cards? Board mode is the Game Builder's grid mode: you place elements on a flat board of cells instead of a free-scrolling world. That's a natural fit for a card table — the felt is a tile layer, and each card is an element you position by hand, carrying its own rank , suit and faceUp data. There's no physics and no camera to chase; the layout is the game state, and your rules read it. (Board mode can also tilt the grid into an isometric view through IsoProjection for tabletop games — for cards we keep it flat and top-down.) Step 1 — A card-table scene Pick New scene → Board . You get a Board (tile) layer for the table surface and a Pieces (entity) layer for the cards. Keeping the felt and the cards on separate layers matters: the felt is static grid data, while the cards are objects your rules deal, flip, and clear. A small grid (here 8×5) is all a card table needs. Step 2 — Lay the felt Select the Board layer,