Mobile development digest: Flutter 3.47 & Dart 3.13, 5 years of Compose & tools

In this edition of our mobile development digest, I cover major updates across the mobile engineering landscape: the releases of Flutter 3.47 and Dart 3.13, celebrating 5 years of Jetpack Compose, Apple App Store header guidelines, and useful open-source tools.

Releases & announcements: Flutter 3.47 & Dart 3.13

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Flutter 3.47

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Flutter 3.47 brings key architectural modularity and performance enhancements:

• Decoupling Material & Cupertino into standalone packages: The Material and Cupertino widget libraries have been decoupled from the core framework into standalone packages on pub.dev: material_ui and cupertino_ui. This enables faster UI updates independent of SDK release cycles and reduces core engine footprint:

// ❌ Legacy monolithic SDK import
import 'package:flutter/material.dart';

// ✅ In Flutter 3.47: standalone packages from pub.dev
import 'package:material_ui/material_ui.dart';
import 'package:cupertino_ui/cupertino_ui.dart';

Step-by-step package migration:

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1. Automated import migration via Dart Fix:

   dart fix --apply --code=migrate_design_widgets

   This command automatically adds material_ui / cupertino_ui to pubspec.yaml and migrates legacy package:flutter/material.dart imports to package:material_ui/material_ui.dart.

2. Compatibility Bridge for legacy dependencies: If third-party packages or subtrees still depend on package:flutter/material.dart, wrap your root app or subtree using MaterialUiCompatibilityBridge (or CupertinoUiCompatibilityBridge) so ThemeData and localizations resolve seamlessly:

   import 'package:material_ui/material_ui.dart';
   
   MaterialApp(
     builder: (context, child) {
       return MaterialUiCompatibilityBridge(child: child!);
     },
     home: const HomeScreen(),
   );

• Impeller renderer enabled by default on Desktop: The next-generation Impeller rendering engine—designed to eliminate runtime shader compilation jank—is now officially enabled by default for Desktop platforms (macOS, Windows, and Linux).
• Flavors & Multi-window support for Desktop: Desktop developers gain official Flutter Flavors support alongside an experimental multi-window API.
• Apple Autumn Release Preparation: Pre-emptively updated for smooth compatibility with upcoming autumn iOS and macOS system updates.
• 📌 Links: Official Flutter 3.47 Announcement | Package material_ui | Package cupertino_ui | Breaking Changes

Dart 3.13

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Alongside Flutter, Dart 3.13 introduced significant language and runtime improvements:

• Stable Primary Constructors: Primary Constructors syntax is officially stable (documentation). Class fields and parameter initialization can now be written concisely directly in the class header:

// ❌ Previously in Dart: explicit fields, constructor declaration, and initializer list
class Point {
  final int x;
  final int y;

  Point(this.x, this.y) : assert(x >= 0 && y >= 0);
}

// ✅ In Dart 3.13 (Primary Constructors): primary constructor directly in the class header
class Point(var int x, var int y) {
  this : assert(x >= 0 && y >= 0) {
    print('Point initialized at ($x, $y)');
  }
}

// Primary constructor with named parameters:
class User({required var String name});

// Constant primary constructor with initializer list (this : z = x + y):
class const ConstPoint(final int x, final int y) {
  final int z;
  this : z = x + y;
}

• WASM Deferred Loading (Experimental in Dart 3.13): The Dart WebAssembly compiler introduced experimental support for deferred module loading. By default, compiled apps do not use deferred loading—it is enabled using the --enable-deferred-loading flag:

$ dart compile wasm --enable-deferred-loading bin/main.dart

Enabling deferred loading requires the JS app loader to supply a loadDeferredModules callback to fetch module bytes on demand:

const app = await compileStreaming(fetch('main.wasm'));
const instantiatedApp = await app.instantiate({}, {
  loadDeferredModules: (modules, handleModuleByteSource) => {
    return Promise.all(
      modules.map((m) => fetch(m).then((r) => handleModuleByteSource(m, r)))
    );
  },
});
instantiatedApp.invokeMain();

• Native Library Tree-Shaking: Introduced compiler annotations to automatically tree-shake unused C/C++ native library functions when building via FFI.
• 📌 Link: Official Dart 3.13 Announcement | Primary Constructors Specification Guide

Android & Jetpack Compose

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• Five years of Jetpack Compose 1.0 🎉 — Google reflects on five years since the first stable release of Jetpack Compose, tracing its evolution from an experimental declarative framework into the default standard for modern Android UI development.
• Stop writing Compose like it’s 2024–10 recent updates every Android developer should know — A comprehensive breakdown of 10 modern Jetpack Compose updates and best practices, helping developers replace outdated 2024 habits for better UI performance and cleaner state handling.

iOS & App Store

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• Apple guidelines for App Store promotional headers — Apple published official guidelines and best practices for creating promotional header assets for App Store features. The document provides visual examples and layout requirements to maximize impression-to-install conversion.

Bonus: Open-source discovery

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• open-video-editor — A handy open-source Android video editor licensed under GPL-3.0 that I recently stumbled upon. Built with Media3 and Jetpack Compose, it supports video trimming, resolution scaling, rotation, and Weblate localization.