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)

Static methods

We know quite a lot about classes already. For example, we know how to turn them into objects and use their methods and variables. But something isn't quite right. Since the very start of the book, we have been using two classes more than any other. We have repeatedly used Log and Toast to output to logcat or the user's screen but have not instantiated them once! How can this be? We never did this:

Log myLog  = new Log();
Toast myToast = new Toast();

We just went ahead and used the classes directly, like this:

Log.i("info","our message here");
Toast.makeText(this, "our message",      
Toast.LENGTH_SHORT).show();

The static methods of classes can be used without first instantiating an object of the class. We can think of this as a static method belonging to the class and all other methods belonging to an object/instance of a class.

And as you have probably realized by now,...