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

Attributes quick summary


In the last few chapters, we have 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 ones.

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.

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 different screens as possible.

So, problem...