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 touches

To get started, 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 the OnTouchEvent method.

Import the MotionEvent class with this line of code:

import android.view.MotionEvent;

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

We will uncover a few details of the MotionEvent class in this project. You can explore the MotionEvent class in full here: https://stuff.mit...