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

Handling touches


In our Pong game, we will have no UI buttons, and therefore cannot use the OnCLickListener interface and override the onClick method. This is not a problem, however. We will just use another interface to suit our situation. We will use OnTouchListener and override the onTouchEvent method. It works a little bit differently, so let's take a look before we dive into the game code.

We must implement the OnTouchListener interface for the activity we want to listen for touches in, like this:

public class MainActivity extends Activity implements View.OnTouchListener{

Then, we can override the onTouchEvent method, perhaps a bit like this:

@Override
public boolean onTouchEvent(MotionEvent motionEvent) {
  
  float x = motionEvent.getX();
  float y = motionEvent.getY();

  //do something with the x and y values

  return false;
}

The variable x will hold the horizontal value of the position on the screen that was touched, and y will hold the vertical position. It is worth noting that the...