Book Image

Android Programming for Beginners - Third Edition

By : John Horton
Book Image

Android Programming for Beginners - Third Edition

By: John Horton

Overview of this book

Do you want to make a career in programming but don’t know where to start? Do you have a great idea for an app but don't know how to make it a reality? Or are you worried that you’ll have to learn Java programming to become an Android developer? Look no further! This new and expanded third edition of Android Programming for Beginners will be your guide to creating Android applications from scratch. The book starts by introducing you to all the fundamental concepts of programming in an Android context, from the basics of Java to working with the Android API. You’ll learn with the help of examples that use up-to-date API classes and are created within Android Studio, the official Android development environment that helps supercharge your mobile application development process. After a crash course on the key programming concepts, you’ll explore Android programming and get to grips with creating applications with a professional-standard UI using fragments and storing user data with SQLite. This Android Java book also shows you how you can make your apps multilingual, draw on the screen with a finger, and work with graphics, sound, and animations. By the end of this Android programming book, you'll be ready to start building your own custom applications in Android and Java.
Table of Contents (30 chapters)

Making decisions in Java

Our Java code will constantly be making decisions. For example, we might need to know whether the user has new messages or whether they have a certain number of friends. We need to be able to test our variables to see whether they meet certain conditions and then execute a certain section of code depending upon whether they do or not.

In this section, as our code gets more complicated, it helps to present it in a way that makes it more readable. Let's look at code indenting to make our discussion about decisions easier.

Indenting code for clarity

You have probably noticed that the Java code in our projects is indented. For example, the first line of code inside the MainActivity class is indented by one tab. Also, the first line of code is indented inside each method. Here is an annotated screenshot to make this clear and as another quick example:

Figure 8.1 – Indented Java code

Notice also that when the indented...