Beginning Flutter

A Hands On Guide to App Development

Marco L. Napoli

• Publisher: Wrox
• Year: 2019
• ISBN:
  9781119550853
• Edition: 1
• Topic: Ciencia de la computación
• Subtopic: Programación de dispositivos móviles

Build your first app in Flutter—no experience necessary!

Beginning Flutter: A Hands-On Guide to App Development is the essential resource for both experienced and novice developers interested in getting started with Flutter—the powerful new mobile software development kit. With Flutter, you can quickly and easily develop beautiful, powerful apps for both Android and iOS, without the need to learn multiple programming languages or juggle more than one code base. This book walks you through the process step by step.

In Flutter, you'll be working with Dart, the programming language of choice for top app developers. Even if you're just starting out in your development career, you can learn Dart quickly, eliminating the barrier to entry for building apps. This is a more efficient way to develop and maintain cross-platform mobile apps, and this book makes the process even easier with a teach-by-example approach.

• Focus on providing quality content by eliminating the need to switch between multiple coding languages
• Learn the ins and outs of Flutter, including all the frameworks, widgets, and tools available to developers
• Accelerate your app development pace, keeping all the code for your cross-platform app in a single code base

• Leapfrog barriers to entry to the mobile software market, creating your first app with no experience necessary

The Flutter community is growing rapidly and transforming the way Android and iOS apps get made. Beginning Flutter allows you to get on board with the latest app development technology, giving your mobile development career a big head start.

PART I
The Foundations of Flutter Programming

• CHAPTER 1: Introducing Flutter and Getting Started
• CHAPTER 2: Creating a Hello World App
• CHAPTER 3: Learning Dart Basics
• CHAPTER 4: Creating a Starter Project Template
• CHAPTER 5: Understanding the Widget Tree

1
Introducing Flutter and Getting Started

WHAT YOU WILL LEARN IN THIS CHAPTER

• What the Flutter framework is
• What Flutter's benefits are
• How Flutter and Dart work together
• What a Flutter Widget is
• What an Element is
• What a RenderObject is
• What type of Flutter widgets are available
• What the stateless and stateful Widget lifecycle is
• How the widget tree and element tree work together
• How to install the Flutter SDK
• How to install Xcode on macOS and Android Studio on macOS, Windows, and Linux
• How to configure an editor
• How to install the Flutter and Dart plugins

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In this chapter, you'll learn how the Flutter framework works behind the scenes. Flutter uses widgets to create the user interface (UI), and Dart is the language used to develop the applications. Once you understand how Flutter handles and implements widgets, it will help you in architecting your apps.

You'll learn how to install the Flutter SDK on macOS, Windows, and Linux. You'll configure Android Studio to install the Flutter plugin to run, debug, and use hot reload. You'll install the Dart plugin for code analysis, code validation, and code completion.

INTRODUCING FLUTTER

Flutter is Google's portable UI framework for building modern, native, and reactive applications for iOS and Android. Google is also working on Flutter desktop embedding and Flutter for the Web (Hummingbird) and embedded devices (Raspberry Pi, home, automotive, and more). Flutter is an open‐source project hosted on GitHub with contributions from Google and the community. Flutter uses Dart, a modern object‐oriented language that compiles to native ARM code and production‐ready JavaScript code. Flutter uses the Skia 2D rendering engine that works with different types of hardware and software platforms and is also used by Google Chrome, Chrome OS, Android, Mozilla Firefox, Firefox OS, and others. Skia is sponsored and managed by Google and is available for anyone to use under the BSD Free Software License. Skia uses a CPU‐based path render and also supports the OpenGL ES2‐accelerated backend.

Dart is the language that you'll use to develop your Flutter applications, and you'll learn more about it in Chapter 3, “Learning Dart Basics.” Dart is ahead‐of‐time (AOT) compiled to native code, making your Flutter application fast. Dart is also just‐in‐time (JIT) compiled, making it fast to display your code changes such as via Flutter's stateful hot reload feature.

Flutter uses Dart to create your user interface, removing the need to use separate languages like Markup or visual designers. Flutter is declarative; in other words, Flutter builds the UI to reflect the state of the app. When the state (data) changes, the UI is redrawn, and Flutter constructs a new instance of the widget. In the “Understanding the Widget Tree and the Element Tree” section of this chapter, you'll learn how widgets are configured and mounted (rendered) creating the widget tree and element tree, but under the hood, the render tree (a third tree) uses the RenderObject, which computes and implements the basic layout and ...