* gradlew lwjgl3:run --args="classname dev.cf.app.crud.CrudApp" ** *
One shell Window hosting four destinations, three of which are listings over a local SQLite * database, plus a detail overlay and a long form. It is the shape most business apps end up * being, and the four decisions below are the ones that are expensive to change later.
* *{@link TabBar} hosts them and keeps them alive across switches, so a tab the user comes back to * is where they left it. Overlays — {@link PartDetailScreen}, {@link PartFormScreen} — are separate * Windows shown on top ({@code new X().show()}, back is {@code hide()}). The rule that follows from * this is short: a thing you navigate away from is a Window; a thing you switch between is * not.
* *Every screen reads {@link Repository} and nothing else. There is no in-memory cache next to it, * because two caches disagree the moment one screen writes. After a write, screens call * {@link #refreshAll()} and re-read — which is cheap, correct, and does not need a change-event * system to be invented for it.
* *{@link FirstLoadScreen} holds navigation while the store fills, and it is the only screen that * can fail visibly. Every other screen in the app is instant by construction.
* *A local edit shows a "not sent" badge on the card, on the detail and as a number on * {@link OutboxTab}. The user never has to guess whether something arrived.
* *Login, permissions, a real transport, conflict resolution, and paging. Each is a genuine * subject and each would double this file's size without teaching anything about the shape. The * seam for the transport is {@link Repository#flushOutbox()}; the seam for paging is * {@link Listing.Items}, which counts and renders rather than taking a list, precisely so a listing * can show more than it has loaded.
*/ public class CrudApp extends Window implements Described { /** Destination indices, in bottom-nav order. */ public static final int TAB_PARTS = 0, TAB_SUPPLIERS = 1, TAB_ORDERS = 2, TAB_OUTBOX = 3; private static final int IC_PARTS = 0xE1DB, IC_SUPPLIERS = 0xE8D1, IC_ORDERS = 0xE8CC, IC_OUTBOX = 0xE2C3; /** Bottom-nav glyphs read better a little larger than body text. */ private static final float NAV_ICON = 1.5f; private TabBar tabs; private PartsTab parts; private SuppliersTab suppliers; private OrdersTab orders; private OutboxTab outbox; @Override public String title() { return "Depot — offline-first CRUD"; } @Override public String note() { return "One shell, three listings over a local database, a detail and a long form. A" + " thing you navigate away from is a Window; a thing you switch between is not."; } /** Hands the palette back to whatever was in force before this app opened. */ @Override public void onRemove() { super.onRemove(); AppTheme.leave(); } @Override public void onAdd(boolean firstTime) throws Exception { if (!firstTime) return; // The brand FIRST: fullscreenColor below reads a token, and reading it before the palette // is declared bakes in the skin's neutral grey for the life of the window. AppTheme.enter(); // The PAGE, not the surface. Cards, buttons and fields are all drawn on the surface, so a // page painted the same colour makes every one of their edges disappear. Read through // onRestyle so a light/dark flip re-derives it instead of keeping the old mode's value. fullscreenColor = AppTheme.pageColor(); onRestyle(() -> fullscreenColor = AppTheme.pageColor()); setLayout(new VerticalLayout(Position.START, Position.START)); // Nothing is built until the store answers. The gate runs the check off the paint thread and // shows itself only when there is work; on a warm store this callback fires within a frame or // two and the user never sees a loading screen. FirstLoadScreen.gate(this::buildShell); } private void buildShell() { try { parts = new PartsTab(this); suppliers = new SuppliersTab(this); orders = new OrdersTab(this); outbox = new OutboxTab(this); tabs = new TabBar(new TabBar.Tab("Parts", MaterialIcon.of(IC_PARTS, NAV_ICON)), new TabBar.Tab("Suppliers", MaterialIcon.of(IC_SUPPLIERS, NAV_ICON)), new TabBar.Tab("Orders", MaterialIcon.of(IC_ORDERS, NAV_ICON)), new TabBar.Tab("Outbox", MaterialIcon.of(IC_OUTBOX, NAV_ICON))); tabs.setContent(parts, suppliers, orders, outbox); // Entering a destination re-reads the store: the user may have edited a part two tabs ago, // and a listing that shows what was true when it was last built is a listing that lies. tabs.onTabChanged(i -> refreshAll()); // A TabBar is a tab strip by default — tabs on TOP, the desktop idiom. A phone app wants // them at the bottom, within reach of a thumb, and that is one flag on the skin's own // style rather than a style of our own: everything else (shape, typography, the tonal pill // behind the active icon) keeps coming from the skin. tabs.style(Skin.get() .tabBar() .copy() .tabsAtBottom(true)); tabs.testTag("crud.tabs"); // Opened from a menu, the app needs a way back to it; as the whole app (the root // window) it has none to go to, and each tab already titles itself. if (!isRoot()) add(0f, new AppBar("Depot", this::hide)); add(LAY_FILL, tabs); // The shell was built after onAdd returned, so the layout it already computed is stale. setValidLayout(false); Screen.repaint(); updateBadge(); } catch (Exception e) { dev.crossfly.util.Debug.handle(e); } } /** * Re-reads the store into every destination. * *Called after any write, and when a destination is entered. Blunt on purpose: at this size * a full re-read costs less than the machinery needed to work out which screens a given write * affected, and it cannot be wrong. Introduce something finer when a measurement, not a * suspicion, says it is needed.
*/ public void refreshAll() { if (parts == null) return; parts.reload(); suppliers.reload(); orders.reload(); outbox.reload(); updateBadge(); Screen.repaint(); } /** Puts the pending count on the Outbox tab, or clears it when there is nothing waiting. */ private void updateBadge() { int n = Repository.get() .pendingCount(); tabs.badge(TAB_OUTBOX, n == 0 ? null : "" + n); } /** * Switches destinations from a child screen. * * @param index one of the {@code TAB_*} constants */ public void goToTab(int index) { tabs.setActiveTab(index); refreshAll(); } }