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)

Attributes quick summary

In the last few chapters, we used and discussed quite a few different attributes. I thought it would be worth a quick summary and further investigation of a few of the more common attributes.

Sizing using dp

As we know, there are thousands of different Android devices. To try and have a system of measurement that works across different devices, Android uses density-independent pixels, or dp, as a unit of measurement. The way this works is by first calculating the density of the pixels on the device an app is running on.

Important Note

We can calculate density by dividing the horizontal resolution by the horizontal size in inches of the screen. This is all done on the fly, on the device on which our app is running.

All we must do is use dp in conjunction with a number when setting the size of the various attributes of our widgets. Using density-independent measurements, we can design layouts that scale to create a uniform appearance on as many...