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)

Exploring a Basic Activity project

Let's look at the Java code first in the MainActivity.java tab in the code editor. As already stated, a Basic Activity project has more to it than an Empty Activity project.

Note

You can open as many instances of Android Studio as you like. If you want to compare projects side by side, select File | Open then choose the project, and when prompted select New Window to open the project, without closing any projects that are already open.

The first thing to note is that there is some extra code in the onCreate method.

The MainActivity.java file

I mentioned very briefly back in Chapter 2, First Contact: Java, XML, and the UI Designer, these interconnections in the Java code and the XML code. Let's look through the resource files and point out the XML files that this Java code points to.

Here is the Java code shown next. I have slightly reformatted it to make it more readable in a book:

Toolbar toolbar = (Toolbar) findViewById...