Intro to Flutter & Dart in 2025

Understanding Flutter

What it is:

Flutter is Google’s open-source UI toolkit for building natively compiled applications for mobile, web, and desktop—from a single codebase—using Dart.

Why it matters:

Unlike React Native or Capacitor, Flutter doesn’t depend on the OS’s UI components. It draws everything itself using Impeller/Skia directly on the GPU, which gives:

• Native-like animations and performance
• Full control over UI appearance
• Consistent rendering across platforms

If you need hardware-specific access (camera, gyroscope, sensors), Flutter lets you bridge into Swift or Kotlin easily via native channels.

Move from FlutterFlow to Full Flutter

Why we switched:

FlutterFlow helped us prototype quickly, but as apps grew (like Tribe Social Mobile), we hit performance and flexibility walls.

Now we use:

• FlutterFlow → rapid MVPs, UI sketches, internal demos
• Flutter → production-ready apps with AI-generated code, custom animations, and native integration

• One codebase
• Fewer limits
• Real control over structure and performance

Learn the Core Philosophy: “Everything Is a Widget”

The mental model:

Everything in Flutter is a widget—text, padding, buttons, even spacing.

Widgets compose hierarchically to describe the UI.

Declarative mindset:

You describe what the UI should look like based on the current state—not how to build it step by step. Flutter handles rendering efficiently.

// UI = f(state)
@override
Widget build(BuildContext context) {
  return Column(
    children: [
      Text("Hello, world!"),
      SizedBox(height: 16),
      ElevatedButton(onPressed: _increment, child: Text("Tap Me"))
    ]
  );
}

That’s the heart of Flutter: UI as a function of state.

Grasp Flutter’s Rendering Engine

How it works:

Flutter skips the OS’s native widgets. Instead, it uses Skia (or Impeller) to render directly to the GPU.

This makes the UI fast, fluid, and pixel-perfect across iOS and Android.

Key points from Jonata’s session:

• Flutter apps have native performance without native UI components.
• The web version lags behind slightly due to bundle size and lack of SEO-friendly HTML.
• PWAs and dashboards shine on Flutter Web; marketing pages still need HTML/CSS.

• Impeller engine deep dive — flutter.dev/impeller

Stateless vs Stateful Widgets

Core difference:

• StatelessWidget → fixed content, doesn’t change (e.g., chat message bubble).
• StatefulWidget → dynamic content that updates (e.g., chat list, toggles).

• Chat message = Stateless (it never changes after sending)
• Chat page = Stateful (it listens for new messages, typing indicators, etc.)

“If your UI depends on dynamic data, make it stateful.

If it’s static, keep it stateless for speed.”

Dart 101: Async and Type Safety

Why Dart works for Flutter:

Dart is modern, fast, and safe. It’s strongly typed, null-safe, and built for async programming.

Quick Primer

Future<String> fetchUserOrder() async {
  await Future.delayed(Duration(seconds: 2));
  return 'Large Latte';
}

Use async / await for clean, predictable asynchronous flows.

Dart’s type safety ensures compile-time checks, reducing runtime surprises.

Learn more

• Dart async guide — dart.dev/codelabs/async-await

Manage State Effectively

State options Jonata covered:

Tip:

Start small with built-ins. Only reach for Provider, Riverpod, or BLoC when your app demands it.

Many teams over-engineer early; Flutter’s native state tools handle most needs.

Flutter Web Reality Check

Strengths:

• Consistent UI across browsers
• Great for PWAs, internal dashboards, and prototypes

• Larger bundle size (slower first load)
• SEO challenges (non-semantic HTML canvas rendering)
• Some browser/device feature gaps

My Practical Workflow (Summing Up)

• Frame before you code. Define appetite and limits early.
• Prototype in FlutterFlow. Fast feedback before full code.
• Build in Flutter. Full control, better performance.
• Let AI assist coding. Use Claude or Cursor to plan, then execute small commits.
• Share as you go. Stream sessions, document learning.

Key Takeaways from the Training

• Flutter = one codebase → iOS, Android, Web, Desktop.
• Rendering = GPU-driven → performance close to native.
• Widgets = building blocks → compose everything declaratively.
• State = scalable → start with setState, expand as needed.