How Does Flutter Work: Everything You Need To Know

Welcome to the world of Flutter, a revolutionary framework developed by Google that has taken the mobile app development landscape by storm.

The primary query that often hovers around in developer circles is – How does Flutter work?

Flutter uses the Dart programming language and its unique approach in using 'widgets' as building blocks simplifies the complete development process.

Flutter has proven itself potent in the creation of beautiful, high-performance mobile apps, which can seamlessly run on multiple platforms. Whether you're a seasoned developer or a beginner, gaining deep insight into "how Flutter works" gives you an edge.

By the end of this blog post, you'll have a clear understanding of the Flutter framework and Flutter app development.

Understanding How Flutter Works - The Basics

The Flutter Framework and the Flutter Engine

At the core of how Flutter works is its layered architecture. This layered system plays a pivotal role in making Flutter stand out among other cross-platform frameworks. Flutter architecture comprises two significant components: the Flutter Framework and the Flutter Engine.

The Flutter framework is packed with a collection of Dart Libraries and top-level Widgets. Flutter widgets turn out to be building blocks in every Flutter app. These widgets include UI elements like buttons, text inputs, sliders, etc., and layout elements like padding, rows, and columns.

The Flutter engine, written in C++, endows the framework with the ability to communicate with underlying platforms. This engine runs important tasks, like graphics (through the Skia rendering engine), managing the Dart runtime, and interaction with platform channels (providing access to device-specific capabilities such as camera and geolocation).

The Dart code you write gets compiled into the native code that directly runs on the Dart VM (Virtual Machine), a just-in-time execution engine. This is a significant factor contributing to high performance apps using Flutter. Your app code, combined with the compiled Flutter SDK, renders on the screen with the Skia graphics library's help.

Deep Dive: Flutter Programming Language

Flutter uses Dart, an object-oriented language that enables developers to create efficient, scalable, and production-ready codebase. Dart, with strong typing and the backing of the Google Flutter team, has emerged as an expedient language for multi-platform mobile app development.

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class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

Dart provides a unique feature in the form of "hot reload," significantly reducing development time for Flutter apps. With hot reloading, changes made in the Dart source code reflect live in the app, removing the need for constant stop-and-restart cycles common in other development environments.

To answer the question – "How does Flutter work?" – it's crucial to understand its central principle where "Everything is a Widget."

From layout specifications like padding and alignment to elements like sliders, buttons, or even the app itself – everything is a widget in Flutter. This allows a remarkably flexible and reusable codebase, making cross-platform development a breeze.

The Flutter framework leverages both Stateful and Stateless widgets within the UI. As the names suggest, Stateful widgets are mutable, changing during runtime, whereas Stateless widgets are immutable, remaining constant.

In our forthcoming sections, we will delve deeper into Flutter app performance, Flutter tools you can use for app development, and prominent examples of Flutter applications.

Understanding Flutter in depth will empower you to leverage its robust potential to its best.

Benefits and Drawbacks of Flutter

Throughout the development process and beyond, Flutter offers some clear-cut advantages and comes up with a few challenges as well. Here's a closer look!

Pros of Flutter

1. Cross-Platform Development

Flutter enables developers to develop applications for iOS and Android from a single codebase. This feature reduces the development time and effort significantly.

2. Hot Reload

The Dart runtime comes with a feature called hot reload that enables developers to view the result of changes in the code in real time without losing the current app state.

3. UI Focused

Widgets are the primary building blocks in Flutter, enabling developers to create highly customizable and engaging user interfaces.

4. Performance

Unlike other cross-platform tools, Flutter does not rely on the webviews for rendering the UI but it directly compiles to native code resulting in high-performance apps that run smoother and faster.

5. Community Support

Being developed by Google, Flutter enjoys robust community support, easy access to libraries and tools and continuous updates.

Cons of Flutter

1. App Size

Flutter applications tend to be larger than native Android or iOS apps.

2. Limited Libraries

While Flutter has decent support for mainstreamed features, for less common ones, developers will have to build their custom functionality.

Decoding the Flutter App

Flutter Apps: Behind the Scenes

Every Flutter application, at its core, is a combination of multiple widgets. These widgets are either stateful or stateless and can themselves include other widgets forming what is a widget tree. It is this widget tree that represents the UI code of your application and gets rendered on your screen.

How are Flutter Apps Compiled?

The Dart code in Flutter applications is directly compiled into the native code for both iOS and Android. The Dart compiler supports two modes of compilation – Just-In-Time (JIT) and Ahead-Of-Time (AOT).

Whilst the JIT mode supports "Hot Reload" functionality and compiles the code during runtime, the AOT compiler, compiles the Dart code to machine code, ensuring fast startup and performance of your applications.

This JIT and AOT capability of Dart makes, "how Flutter works" intriguing. The perfect blend of these two modes significantly reduces the development time while assuring a native-like app performance. This is a crucial aspect that makes the Flutter framework a preferred choice for cross-platform applications.

Notable Examples of Flutter Apps

There are notable examples in industries that demonstrate the efficiency of Flutter applications.

1. Google Ads

One of the prime examples of Flutter apps, Google Ads provides a seamless user experience. The simplicity of the UI elements and speed signify the power of Flutter.

2. Alibaba

The eCommerce giant has incorporated Flutter for crafting parts of its application. Impactful UI, smooth animations, and the solid performance of the app demonstrate the capability of Flutter.

3. Reflectly

Reflectly, a lifestyle app, is another prominent example showcasing the potential of Flutter. The app has an intuitive UI, seamless navigation, and an overall appealing design.

The prospects of a fast development cycle, smooth UI code, and a single codebase for multiple platforms, make Flutter an attractive package.

As we delve deeper into the understanding of how Flutter works, the intricacies of this platform-agnostic framework intrigue developers all the more.

Getting Started with Flutter: A How-To Guide

Set-Up: How to Install and Run Flutter

If you're excited to get hands-on experience with Flutter, here's a step-by-step guide:

1. System Requirements

For Windows:

• Disk Space: Flutter uses approximately 1.64 GB, but due to the development tools being installed alongside Flutter, 10 GB of free disk space is recommended.

• Tools: Flutter depends on these command-line tools being available in your environment: bash, mkdir, rm, git, curl, unzip, and which.

For MacOS:

• Disk Space: Flutter uses 2.8 GB on MacOS, but due to the development tools being installed alongside Flutter, 10 GB of free disk space is recommended.

• Tools: Flutter depends on these command-line tools being available in your environment: bash, mkdir, rm, git, curl, unzip, and which.

2. Installing Flutter

To get Flutter, use git to clone the Flutter repo to your local machine and for the stable release, use the stable branch:

3. Setting up the Flutter Development Environment

Update your path with flutter/bin for accessing the Flutter command directly from your terminal/console.

Build Processes: Flutter App Development

In the process of building apps, Flutter provides a command-line tool, Flutter Doctor, to guide developers through the setup.

The flutter doctor command examines your environment and produces a report on the status of your Flutter installation. The Dart SDK is included with Flutter; you do not need to install Dart individually.

It creates a simple, templated Flutter app named myapp. myapp here represents the Dart package name following Dart's package naming conventions.

Conclusion - Is Flutter Good for Your Project?

Opting for Flutter for your next project can be a strategic move, considering its numerous pros. Flutter's architecture, based on Dart language, the robust Flutter SDK, combined with built-in widgets and an efficient mechanism for rendering these widgets onto a Skia canvas, makes it an excellent choice for early-stage startups and even established businesses.

The app code sample above shows a UI constructed from a tree of widgets like MaterialApp, Scaffold , AppBar , and Center. You can witness how simple it is to create a UI in Flutter.

With platform-agnostic features, a simplified development process, and powerful performance, Flutter allows you to build beautiful, natively compiled applications for multiple devices from a single codebase.

Although the learning curve might seem steep initially, it's worth it. With a clear understanding of the nitty-gritty of how Flutter works, you're all set to explore the world of Flutter applications.

Happy coding!

Row(
  children: <Widget>[
    RedWidget(),
    BlueWidget(),
    YellowWidget(),
  ],
)

flutter run // start the app

// Make changes in your Dart code
flutter hot reload // Reflect the changes in the app.

git clone https://github.com/flutter/flutter.git -b stable

flutter doctor

// Run this command in your terminal/console
flutter create myapp

return MaterialApp(
  title: 'Flutter App',
  home: Scaffold(
    appBar: AppBar(
      title: Text('Your First Flutter App'),
    ),
    body: Center(
      child: Text('Hello, world!'),
    ),
  ),
);