Book Image

Android Programming for Beginners

By : John Horton, Paresh Mayani
Book Image

Android Programming for Beginners

By: John Horton, Paresh Mayani

Overview of this book

Android is the most popular OS in the world. There are millions of devices accessing tens of thousands of applications. It is many people's entry point into the world of technology; it is an operating system for everyone. Despite this, the entry-fee to actually make Android applications is usually a computer science degree, or five years’ worth of Java experience. Android Programming for Beginners will be your companion to create Android applications from scratch—whether you’re looking to start your programming career, make an application for work, be reintroduced to mobile development, or are just looking to program for fun. We will introduce you to all the fundamental concepts of programming in an Android context, from the Java basics to working with the Android API. All examples are created from within Android Studio, the official Android development environment that helps supercharge your application development process. After this crash-course, we’ll dive deeper into Android programming and you’ll learn how to create applications with a professional-standard UI through fragments, make location-aware apps with Google Maps integration, and store your user’s data with SQLite. In addition, you’ll see how to make your apps multilingual, capture images from a device’s camera, and work with graphics, sound, and animations too. By the end of this book, you’ll be ready to start building your own custom applications in Android and Java.
Table of Contents (37 chapters)
Android Programming for Beginners
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

All Android UI elements are classes too


When our app is run and the setContentView method is called from onCreate, the layout is inflated from XML UI classes and loaded into memory as usable objects. They are stored in a part of the DVM memory called the heap.

Reintroducing references

However, where are all these UI objects/classes? We certainly can't see them in our code. And how on earth do we get our hands on them?

The DVM inside every Android device takes care of memory allocation to our apps. In addition, it stores different types of variables in different places.

Variables that we declare and initialize in methods are stored in the area of memory that is known as the stack. We can stick to our existing warehouse analogy when talking about the stack—almost. We already know how we can manipulate variables on the stack. So, let's talk about the heap and what is stored there.

Note

Important fact: All objects of classes are reference type variables and are just references to the actual objects...