Book Image

Android UI Development with Jetpack Compose

By : Thomas Künneth
Book Image

Android UI Development with Jetpack Compose

By: Thomas Künneth

Overview of this book

Jetpack Compose is Android’s new framework for building fast, beautiful, and reliable native user interfaces. It simplifies and significantly accelerates UI development on Android using the declarative approach. This book will help developers to get hands-on with Jetpack Compose and adopt a modern way of building Android applications. The book is not an introduction to Android development, but it will build on your knowledge of how Android apps are developed. Complete with hands-on examples, this easy-to-follow guide will get you up to speed with the fundamentals of Jetpack Compose such as state hoisting, unidirectional data flow, and composition over inheritance and help you build your own Android apps using Compose. You'll also cover concepts such as testing, animation, and interoperability with the existing Android UI toolkit. By the end of the book, you'll be able to write your own Android apps using Jetpack Compose.
Table of Contents (16 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 axis-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 – The sample PredefinedLayoutsDemo app

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