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Android Programming for Beginners

You're reading from   Android Programming for Beginners Build in-depth, full-featured Android 9 Pie apps starting from zero programming experience

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Product type Paperback
Published in Oct 2018
Publisher Packt
ISBN-13 9781789538502
Length 766 pages
Edition 2nd Edition
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Author (1):
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John Horton John Horton
Author Profile Icon John Horton
John Horton
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Table of Contents (33) Chapters Close

Preface 1. Beginning Android and Java FREE CHAPTER 2. First Contact – Java, XML, and the UI Designer 3. Exploring Android Studio and the Project Structure 4. Getting Started with Layouts and Material Design 5. Beautiful Layouts with CardView and ScrollView 6. The Android Lifecycle 7. Java Variables, Operators, and Expressions 8. Java Decisions and Loops 9. Java Methods 10. Object-Oriented programming 11. More Object-Oriented Programming 12. The Stack, the Heap, and the Garbage Collector 13. Anonymous Classes – Bringing Android Widgets to Life 14. Android Dialog Windows 15. Arrays, ArrayList, Map and Random Numbers 16. Adapters and Recyclers 17. Data Persistence and Sharing 18. Localization 19. Animations and Interpolations 20. Drawing Graphics 21. Threads, and Starting the Live Drawing App 22. Particle Systems and Handling Screen Touches 23. Supporting Different Versions of Android, Sound Effects, and the Spinner Widget 24. Design Patterns, Multiple Layouts, and Fragments 25. Advanced UI with Paging and Swiping 26. Advanced UI with Navigation Drawer and Fragment 27. Android Databases 28. Coding a Snake Game Using Everything We Have Learned So Far 29. Enumerations and Finishing the Snake Game 30. A Quick Chat Before You Go Other Books You May Enjoy Index

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 as follows:

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

or

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

Straight away, this can seem unwieldy, but what about when someone gets a new top score or we want to let our users sort the order their notes are displayed in? Using the high scores scenario, we have to 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, what we need is a Java array. An array is a reference...

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