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)

Handling large amounts of data with arrays

You might be wondering what happens when we have an app with lots of variables to keep track of. What about our Note to Self app with 100 notes or a high score table in a game with the top 100 scores? We could declare and initialize 100 separate variables like this:

Note note1;
Note note2;
Note note3;
// 96 more lines like the above
Note note100;

Or we could do this:

int topScore1;
int topScore2;
int topScore3;
// 96 more lines like the above
int topScore100;

Straight away, this might seem unwieldy, but what about when someone gets a new top score or we want to let our users sort the order that their notes are displayed in? Using the high scores scenario, we must shift the scores in every variable down one place. A nightmare begins:

topScore100 = topScore99;
topScore99 = topScore98;
topScore98 = topScore97;
// 96 more lines like the above
topScore1 = score;

There must be a better way. When we have a whole array of variables...