Book Image

Android Programming for Beginners

By : John Horton, Paresh Mayani
Book Image

Android Programming for Beginners

By: John Horton, Paresh Mayani

Overview of this book

Android is the most popular OS in the world. There are millions of devices accessing tens of thousands of applications. It is many people's entry point into the world of technology; it is an operating system for everyone. Despite this, the entry-fee to actually make Android applications is usually a computer science degree, or five years’ worth of Java experience. Android Programming for Beginners will be your companion to create Android applications from scratch—whether you’re looking to start your programming career, make an application for work, be reintroduced to mobile development, or are just looking to program for fun. We will introduce you to all the fundamental concepts of programming in an Android context, from the Java basics to working with the Android API. All examples 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, make location-aware apps with Google Maps integration, and store your user’s data with SQLite. In addition, you’ll see how to make your apps multilingual, capture images from a device’s camera, 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 (37 chapters)
Android Programming for Beginners
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Drawing with canvas and paint


So far, we have been using the Android Studio UI designer to implement all aspects of our interface with which our users interact.

If we want smooth-moving customized graphics, then we need to move away from predefined UI widgets.

We are going to need to start looking at and designing with individual pixels and lines. Fortunately, as you might have guessed, Android has some classes to make this nice and easy for us. We will be learning how to get started with the Canvas and Paint classes.

To achieve this, we will learn about the coordinate system that we use to draw our pixels and lines. Then, we will look at the Paint and Canvas classes themselves.

The Android coordinate system

A pixel is the smallest graphical element we can manipulate using the Paint and Canvas classes. It is essentially a dot. If your device resolution is 1920 x 1080 like the Nexus 5 emulator, then we have 1920 pixels across the longest length of the device and 1080 across the other.

We can therefore...