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

Handling touches


To get started with this conversation, add the OnTouchEvent method to the LiveDrawingView class:

@Override
public boolean onTouchEvent(MotionEvent motionEvent) {

   

   return true;
}

This is an overridden method and it is called by Android every time the user interacts with the screen. Look at the one and only parameter of onTouchEvent.

It turns out that motionEvent has a whole bunch of data tucked away inside of it, and this data contains the details of the touch that just occurred. The operating system sent it to us because it knows we will probably need some of it.

Notice that I said some of it. The MotionEvent class is quite extensive. It contains within it dozens of methods and variables.

Note

Over the course of this book, we will uncover quite a lot of them, but nowhere near all of them. You can explore the MotionEvent class here:

https://stuff.mit.edu/afs/sipb/project/android/docs/reference/android/vie w/MotionEvent.html.

Note that it is not necessary to do further...