Book Image

Android 9 Development Cookbook - Third Edition

By : Rick Boyer
Book Image

Android 9 Development Cookbook - Third Edition

By: Rick Boyer

Overview of this book

The Android OS has the largest installation base of any operating system in the world. There has never been a better time to learn Android development to write your own applications, or to make your own contributions to the open source community! With this extensively updated cookbook, you'll find solutions for working with the user interfaces, multitouch gestures, location awareness, web services, and device features such as the phone, camera, and accelerometer. You also get useful steps on packaging your app for the Android Market. Each recipe provides a clear solution and sample code you can use in your project from the outset. Whether you are writing your first app or your hundredth, this is a book that you will come back to time and time again, with its many tips and tricks on the rich features of Android Pie.
Table of Contents (24 chapters)
Title Page
Copyright and Credits
Dedication
About Packt
Contributors
Preface
Index

Introduction


In Android, the user interface is defined in a layout. A layout can be declared in XML or created dynamically in code. (It's recommended to declare the layout in XML rather than in code to keep the presentation layer separate from the implementation layer.) A layout can define an individual ListItem, a fragment, or even the entire activity. Layout files are stored in the /res/layout folder and referenced in code with the following identifier: R.layout.<filename_without_extension>.

Android provides a useful variety of Layout classes that contain and organize individual elements of an activity (such as buttons, checkboxes, and other Views). The ViewGroup object is a container object that serves as the base class for Android's family of Layout classes. The Views placed in a layout form a hierarchy, with the topmost layout being the parent.

Android provides several built-in layout types designed for specific purposes, such as RelativeLayout, which allows Views to be positioned...