dartvel_flutter 0.9.2

The Flutter runtime for Dartvel apps, with pages, DVBox/DVText UI primitives, signals, typed routing, Studio, and SEO and PWA on the web.

dartvel_flutter

The Flutter runtime of Dartvel: everything a Dartvel application runs on the device, in the browser and on the desktop.

• DVBox and DVText, styled through Dartvel's own DVModifier chain.
• Signals: context.signal(...), signals derived with operators, reactive data models and DV.global.
• The runtime behind file-based pages and typed routes: the page shell, DVNavLink, DV.Navigation, layouts, loading and error pages.
• The widgets generated data models use: forms, tables and model pages.
• DV.Platform, the device API surface, reached through dart:ffi, jnigen and dart:js_interop rather than platform channels.
• On the web: head tags and structured data per page, path URLs, and the install prompt of the generated PWA.
• Dartvel Studio's page builder and admin sections, which a web-server build serves.

Dartvel is alpha. Each part of it is labelled in docs/spec-status.json as Shipped, Partial or Designed, and a check in the repository fails when a section claims evidence that does not exist. This page shows Shipped surfaces as ready to use and says so where one is Partial.

How it is used

Most of this package is meant to be reached through code that Dartvel generates. A Dartvel project is made with dartvel create. You write pages, data models and backend functions as private annotated declarations, and the CLI writes lib/dartvel_client/ from them: the router, one typed target per page on DVRoutes, the public model classes and their forms, and the client for each backend function. Application code imports that one barrel, which re-exports this package:

import '../dartvel_client/dartvel_client.dart';

Generation runs by itself before dartvel dev and dartvel build, so you rarely call it by name. The generated directory is not committed; a fresh clone generates it on its first build.

Part of the package needs no generated code, and works in any Flutter app:

Works on its own	Needs the generator
DVBox, DVText, DVModifier	Pages (@DVPage) and the router
context.signal, signal(context, v), derived signals	DVRoutes, and so DVNavLink and DV.Navigation
DV.global, context.global	Data models: User, User.Form(), User.Table(...), User.Page
	Native bindings, which the generated app registers at startup
	SEO, sitemap and PWA files, written by dartvel build web

Routing is on the right on purpose. A route written as a string drifts the moment its page moves, and the generated targets turn that into a compile error. Without the generator there are no targets to use.

Install

For a Dartvel application, install the CLI and let it write the project:

dart pub global activate dartvel_cli
dartvel create shop
cd shop && dartvel dev

The project it writes already depends on dartvel_flutter, dartvel_core and dartvel_shelf. To use only the parts that need no generator in an existing Flutter app:

flutter pub add dartvel_flutter

import 'package:dartvel_flutter/dartvel_flutter.dart';

Every Dartvel package declares the same floor: Dart 3.13 and Flutter 3.47. dartvel init adds Dartvel to an existing Flutter project instead of making a new one, and dartvel init --dry-run shows what it would change first.

A small app

This is a generated project with two pages. lib/main.dart is what dartvel create writes:

import 'package:flutter/material.dart';
import 'dartvel_client/dartvel_client.dart';

void main(List<String> arguments) async {
  await negotiateDartvelLaunch(arguments);
  runApp(createDartvelApp(arguments: arguments));
}

Widget createDartvelApp({List<String> arguments = const <String>[]}) {
  return MaterialApp.router(
    title: 'Shop',
    routerConfig: createDartvelRouter(arguments: arguments),
  );
}

lib/pages/index.dart is served at /:

import 'package:flutter/widgets.dart';

import '../dartvel_client/dartvel_client.dart';

@DVPage(title: 'Shop', description: 'House espresso, roasted this week.')
@pragma('vm:entry-point')
Widget _indexPage(BuildContext context) {
  final DVSignal<int> quantity = context.signal(1);
  final DVSignal<int> unitPrice = context.signal(1450);
  final total = unitPrice * quantity;

  return DVBox.list(<Widget>[
    const DVText('House espresso').modifier(
      DVModifier().fontSize(28).fontWeight(FontWeight.w700).semanticHeading(1),
    ),
    DVText('${quantity.value} bags, EUR ${(total.value / 100).toStringAsFixed(2)}'),
    const DVText('Add one').modifier(
      DVModifier()
          .paddingSymmetric(horizontal: 16, vertical: 10)
          .rounded(8)
          .semanticButton()
          .onTap(() => quantity.value = quantity.value + 1),
    ),
    DVNavLink(to: DVRoutes.about, child: const DVText('About the roastery')),
  ]).modifier(const DVModifier().padding(24));
}

lib/pages/about.dart is served at /about, and generating it is what puts DVRoutes.about on the index page:

import 'package:flutter/widgets.dart';

import '../dartvel_client/dartvel_client.dart';

@DVPage(title: 'About')
@pragma('vm:entry-point')
Widget _aboutPage(BuildContext context) => const DVBox.list(<Widget>[
      DVText('We roast on Tuesdays.'),
    ]);

Two rules the generator enforces. The annotated function is private (_aboutPage, not aboutPage), because Dartvel generates the public API from it and a public annotated input is an error. And a page does not build its own Scaffold: @DVPage owns the page shell, so title, showAppBar and the rest go on the annotation.

example/ in this package is a runnable app that uses only the parts that need no generator.

UI: DVBox, DVText and the modifier chain

DVBox is the one layout primitive and DVText the one text primitive. Both take a DVModifier, an immutable chain of styling, layout, interaction and semantics. The chain is Dartvel's own, rendered with Flutter widgets; it is not built on mix.

Widget card() => DVBox(
      const DVText('One child, with padding and a border'),
      const DVModifier()
          .padding(16)
          .backgroundColor(Color(0xFFF4F6FB))
          .border(Border.fromBorderSide(BorderSide(color: Color(0xFFE3E7EF))))
          .rounded(12),
    );

DVBox(child) is for one child. A collection uses a named constructor, so the layout is said once, where the children are:

Widget layouts(BuildContext context) => DVBox.list(<Widget>[
      const DVBox.row(<Widget>[
        DVText('Left'),
        DVText('Right'),
      ], align: DVAlign.spaceBetween),
      const DVBox.wrapLine(<Widget>[
        DVText('Dart'),
        DVText('Flutter'),
        DVText('Web'),
      ], spacing: 12),
      // Up to four columns, fewer on narrow screens.
      DVBox.grid(<Widget>[
        for (int i = 1; i <= 8; i++) DVText('Item $i'),
      ], columns: context.screen.value<int>(mobile: 1, tablet: 2, desktop: 4)),
    ], spacing: 24);

The others are DVBox.scrollableList, DVBox.horizontalScrollable, DVBox.stack, DVBox.masonry and DVBox.twoPane, which splits across a foldable's hinge and stacks on a phone. DVBox.image, DVBox.video and DVBox.audio are boxes whose content is media.

Interaction and semantics are on the same chain, so a tappable label is a DVText rather than a button widget wrapped round one:

Widget saveButton(VoidCallback onSave) => DVText('Save').modifier(
      const DVModifier()
          .paddingSymmetric(horizontal: 20, vertical: 12)
          .backgroundColor(Color(0xFF2F6BFF))
          .color(Color(0xFFFFFFFF))
          .rounded(8)
          .animate(Duration(milliseconds: 150))
          .hover(DVModifier().opacity(0.9))
          .minimumTapTarget()
          .semanticButton()
          .onTap(onSave),
    );

The Styling section is Partial: the chain covers padding, borders, radius, colour, gradients, type, shadows, opacity, blur, rotation, hover and animation, and the named design tokens the spec describes are not built yet.

Signals

A signal is a value a widget reads; reading .value in build redraws that widget when the value changes. context.signal(initial) creates one for the widget, and signal(context, initial) is the same call as a function. Signals are matched by call order in build, like hooks, so create them unconditionally.

final DVSignal<int> quantity = context.signal(1);

quantity.value = 3;                  // set
quantity.update((int n) => n + 1);   // set from the current value
final int now = quantity.read();     // read without subscribing

An operator on a signal returns a signal that tracks its sources. There is no separate computed type:

final DVSignal<int> price = context.signal(1200);
final DVSignal<int> quantity = context.signal(2);
final DVSignal<bool> agreed = context.signal(false);
final DVSignal<bool> paid = context.signal(false);

final subtotal = price * quantity;   // + - * / ~/ % on numbers
final expensive = subtotal >= 10000; // < <= > >= give a bool signal
final canShip = agreed & paid;       // & | ^ on bools

Read .value of a derived signal in build to redraw with it. == and ! are not overloaded, so compare .value instead.

One object shared across the app is registered with DV.global. There is no separate service container:

DV.global<Cart>(Cart());                 // register, at startup
final Cart cart = DV.global<Cart>();     // read anywhere; throws if unregistered
final Cart same = context.global<Cart>(); // read, and redraw when it is replaced

A generated data model is reactive too: article.signal(context) gives a signal of that record, and Article.Page.signal(...) redraws the model's page from it.

Pages and routing

A file in lib/pages/ is a page. lib/pages/blog/[id].dart is served at /blog/:id, and its parameters and query are on the context:

@DVPage(title: 'Blog post')
Widget _blogPostPage(BuildContext context) => DVBox.list(<Widget>[
      DVText('Post ${context.dvParams['id']}'),
      DVText('Sorted by ${context.dvQuery['sort'] ?? 'date'}'),
    ]);

Every page is a typed target on the generated DVRoutes, and navigation takes only targets:

DVNavLink(to: DVRoutes.about, child: const DVText('About us'))

DVText('Open post 7').modifier(
  DVModifier().onTap(DV.Navigation.to(DVRoutes.blog(id: '7'))),
)

// A query is still a typed route: both halves are generated targets.
DV.Navigation.to(
  DVRoutes.signin.withQuery(<String, String>{'from': DVRoutes.account.path}),
)

DV.Navigation.to returns a callback rather than navigating, so it goes where a handler is expected. Written as onTap: () => DV.Navigation.to(target) it builds the callback and throws it away; the analyzer flags that through @useResult. DV.Navigation.navigate, push and back act immediately.

DVNavLink is a link, not a tap handler. It navigates with its padding as part of the hit area, is announced to a screen reader as a link carrying its destination, takes keyboard focus and answers Enter, opens beside the page on a middle or modifier click, preloads the route's deferred code when it becomes visible, and shows a preview of the destination on a resting pointer or a long press. DVNavLink.external(url, child: ...) is the same for an address outside the app.

Beside the pages:

• _layout.dart in a folder wraps every page under it, as a class extending DartvelLayout.
• about.loading.dart and about.error.dart are shown while about.dart's data loads and when it fails.
• _guard.dart runs before every page in its folder, and @DVPage(policy: ...) puts a page behind an authorization policy.

Every page can be reached by keyboard, a TV remote's D-pad and switch control with nothing added: the page shell carries keyboard scrolling, D-pad focus and switch scanning, and they stay inert until used. The reader's own choices live on DV.Accessibility.switchControl:

DV.Accessibility.switchControl.enabled = true;

Data models and forms

A data model is declared once, as a private class, and the generator writes the public class with its schema, CRUD, validation and serialization. The annotation comes from dartvel_core; the widgets the model gets are built on this package:

// lib/models/article.dart
import 'package:dartvel_core/dartvel.dart';

@DVModel()
class const _Article({
  required final String slug,
  required final String title,
  required final bool published,
});

Widget newArticleForm() => Article.Form();              // creates a record
Widget editArticleForm(Article a) => a.Form();          // edits this record
Widget articleTable(List<Article> all) => Article.Table(all);
Widget articlePage(Article a) => Article.Page.sync(a);

A form takes no save callback. Saving is what the form does, and whether the reader may create or edit is answered by the model's policy, the same one the page and the backend function ask.

Device APIs

DV.Platform is one surface on every target. A feature the platform does not have reports that it is unavailable, and calling a name nothing has bound throws and names it, rather than returning a plausible default.

Future<void> shareReceipt(String orderId) async {
  await DV.Haptics.lightVibrate();
  await DV.Share.shareText('Order $orderId is on its way.');
}

Connectivity is a signal, so an offline banner is a widget that rebuilds:

final DVNetworkStatus status = DV.Platform.network.watch(context);
// online, metered, offline or unknown

The bindings reach native code through dart:ffi (X11, GTK and GDBus on Linux, the Win32 API, the Objective-C runtime on Apple platforms), dart:js_interop on the web and jnigen on Android. There are no platform channels. Coverage differs by platform, by design and by progress: a browser tab has no system tray, and on Android biometrics and NFC need an Activity rather than a Context. The Platform section is Partial, and its entry in docs/spec-status.json lists what each target binds and why the rest is absent. The generated app registers the bindings for its target at startup.

The web: SEO and PWA

A page's title and description on @DVPage become its title, meta description, Open Graph tags and structured data. dartvel build web writes one prerendered HTML page per route, with those head tags and text a crawler can read, plus sitemap.xml and robots.txt. Routes behind a guard are left out of the sitemap. A page can tune its own entry:

@DVPage(
  title: 'Pricing',
  sitemap: DVPageSitemap(
    priority: 0.8,
    changeFrequency: DVSitemapChangeFrequency.weekly,
  ),
)
Widget _pricingPage(BuildContext context) => const DVText('Plans');

The same build writes the PWA: manifest, icons, service worker and an offline page. A same-origin request other than a GET that cannot be sent while offline is queued by the worker and sent in order when the network returns. The install prompt is on DV.Platform:

if (DV.Platform.install.canPrompt) {
  final DVInstallOutcome outcome = await DV.Platform.install.prompt();
}

canPrompt is false until the browser says the app is installable, and prompt() must run inside a user gesture, because browsers refuse it otherwise.

URLs are paths rather than Flutter's default #/ fragments, so a deep link reaches the page it names.

Studio

Dartvel Studio is a visual page builder and data editor. It lives in this package and is served by a web-server build at /__studio, to accounts that have been granted access; it is never compiled into an app:

dartvel:
  admin:
    enabled: true

dartvel build web-server
dartvel admin grant <user-id> --database dartvel_data/data.db

In a web app served by its own server, a page published from Studio takes over its route on the next load without a rebuild, and reverting it gives the route back to the compiled page. A page exported from Studio is ordinary Dartvel source.

Platform notes

• Web. dartvel.dev is built with this package, and runs as a static build.
• Desktop (multi-window is Partial). DV.Platform.Window.open(route) never fails: where a real window cannot be created it navigates to the route instead and reports why. Real OS windows need the separate dartvel_windowing package, which is not published, because it depends on Flutter's internal windowing API.
• Terminal (Partial). dartvel build linux-cli renders the same app in a terminal. It is opt-in at build time, so no other build links terminal code.
• Embedded and TV targets (Tizen, webOS, Sony eLinux, tvOS) are built through each vendor's embedder. Status and evidence per target are in docs/build-targets.md; some targets have been built and not run, and Fuchsia does not build.

Links

• API reference
• Repository
• Getting started
• NEW_SPEC.md, the design specification. It describes where Dartvel is going; where it and the code disagree, the code wins.
• Implementation status per spec section
• dartvel.dev

The name

The framework is Dartvel and the command is dartvel. The pub.dev package for the CLI is dartvel_dev because dartvel was taken on 2026-08-06 by an unrelated package.