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)

Trying out expressions

Let's try using some declarations, assignments, and operators. When we bundle these elements together into some meaningful syntax, we call this an expression. Let's write a quick app to try some expressions out. We will then use Toast and Log to check our results.

Expressing Yourself demo app

Create a new project called Expressing Yourself, use the Basic Activity project, and leave all the other settings at their defaults. The completed code that we will write in this project can be found in the Chapter 7/Expressing Yourself folder of the download bundle.

Switch to the MainActivity.java tab in the editor, and we will write some code. In the onCreate method, just before the } closing curly brace, add this code:

int numMessages;

Directly below the previous line of code, we will initialize a value to numMessages.

Next, add this line of code:

numMessages = 10;

Immediately after the previous line of code and before the }closing curly...