Book Image

Android Programming for Beginners - Second Edition

By : John Horton
Book Image

Android Programming for Beginners - Second Edition

By: John Horton

Overview of this book

Are you trying to start a career in programming, but haven't found the right way in? Do you have a great idea for an app, but don't know how to make it a reality? Or maybe you're just frustrated that in order to learn Android, you must know Java. If so, then this book is for you. This new and expanded second edition of Android Programming for Beginners will be your companion to create Android Pie applications from scratch. We will introduce you to all the fundamental concepts of programming in an Android context, from the basics of Java to working with the Android API. All examples use the up-to-date API classes, and 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 and store your user's data with SQLite. In addition, you'll see how to make your apps multilingual, draw to the screen with a finger, 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 (35 chapters)
Android Programming for Beginners - Second Edition
Contributors
Preface
Other Books You May Enjoy
Index

Expressions


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

Expressing yourself demo app

Create a new project called Expressing Yourself, use a Basic Activity, 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 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. But as you begin to type nu... , notice that we get a little pop up message like this:

If you look at the first choice in the pop up message, you'll notice that it is, in fact, numMessages. Android Studio...