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

Getting dynamic with arrays


As we discussed at the beginning of all this array stuff, if we need to declare and initialize each element of an array individually, there isn't a huge amount of benefit to an array over regular variables. Let's look at an example of declaring and initializing arrays dynamically.

Dynamic array example

Let's make a simple dynamic array example. You can get the working project for this example in the download bundle. It can be found in the Chapter 15/Dynamic Array Example/MainActivity.java folder.

Create a project with an empty Activity and call it Dynamic Array Example.

Type the following just after the call to setContentView in onCreate. See if you can work out what the output will be before we discuss it and analyze the code:

// Declaring and allocating in one step
int[] ourArray = new int[1000];

// Let's initialize ourArray using a for loop
// Because more than a few variables is allot of typing!

for(int i = 0; i < 1000; i++){

   // Put the value of our value...