Book Image

Android UI Development with Jetpack Compose - Second Edition

By : Thomas Künneth
5 (1)
Book Image

Android UI Development with Jetpack Compose - Second Edition

5 (1)
By: Thomas Künneth

Overview of this book

Compose has caused a paradigm shift in Android development, introducing a variety of new concepts that are essential to an Android developer’s learning journey. It solves a lot of pain points associated with Android development and is touted to become the default way to building Android apps over the next few years. This second edition has been thoroughly updated to reflect all changes and additions that were made by Google since the initial stable release, and all examples are based on Material 3 (also called Material You). This book uses practical examples to help you understand the fundamental concepts of Jetpack Compose and how to use them when you are building your own Android applications. You’ll begin by getting an in-depth explanation of the declarative approach, along with its differences from and advantages over traditional user interface (UI) frameworks. Having laid this foundation, the next set of chapters take a practical approach to show you how to write your first composable function. The chapters will also help you master layouts, an important core component of every UI framework, and then move to more advanced topics such as animation, testing, and architectural best practices. By the end of this book, you’ll be able to write your own Android apps using Jetpack Compose and Material Design.
Table of Contents (18 chapters)
Part 1: Fundamentals of Jetpack Compose
Part 2: Building User Interfaces
Part 3: Advanced Topics

Using predefined layouts

When you create a UI, you must define where its elements appear and how big they are. Jetpack Compose provides a couple of basic layouts, which arrange their content along one main axis. There are three axes to consider:

  • Horizontal
  • Vertical
  • Stacked

Each axis is represented by a layout. Row() arranges its content horizontally, while Column() does so vertically. Box() and BoxWithConstraints() stack their contents on top of each other. By combining these axes-orientated building blocks, you can create great-looking UIs easily.

Combining basic building blocks

The following PredefinedLayoutsDemo sample app shows three checkboxes that toggle a red, a green, and a blue rectangle, respectively. The boxes appear only if the corresponding checkbox is checked:

Figure 4.1 – Sample PredefinedLayoutsDemo app

Figure 4.1 – Sample PredefinedLayoutsDemo app

Let’s see how this is done. First, I will show you how to create a checkbox with an accompanying...