Grant Allen

Android for Absolute Beginners

Getting Started with Mobile Apps Development Using the Android Java SDK

1st ed.
Grant Allen
LONDON, UK
ISBN 978-1-4842-6645-8e-ISBN 978-1-4842-6646-5
https://doi.org/10.1007/978-1-4842-6646-5
© Grant Allen 2021
This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed.
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The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

This Apress imprint is published by the registered company APress Media, LLC part of Springer Nature.

The registered company address is: 1 New York Plaza, New York, NY 10004, U.S.A.

To all the aspiring new Android developers in the world, may you have fun while you learn to build new and wonderful applications!

Introduction

A book for beginners with Android development should provide enough subject matter to spur the imagination and lay a foundation for future learning and experimentation. The trick is to make sure the content doesn’t overload you, the reader, or leave you at your wit’s end as to how to get started.

In this book, I have tried to balance giving you a firm foundation in the core concepts and techniques you will need to get started, without packing in every possible topic that might be of use to you eventually. That would have resulted in thousands and thousands more pages of content, which gets to the point of being counterproductive.

You will see and create a wide range of applications based on the topics covered in the 20 chapters presented here, and I’ve also provided a range of pointers to more online content at Apress, Google, and other websites that take some of the topics beyond the beginner’s realm. This book is a beginning, and where you go from here is entirely up to you!

Acknowledgments

Writing a book during a global pandemic is a strange experience and only made possible with the help of all the folks at Apress and the technical reviewer. I’d like to thank Steve Anglin, Val Okafor, Mark Powers, Matthew Moodie, and all the other people at Apress who made this book a reality.

I would also like to thank Google for continuing to make Android a fun and dynamic platform on which to learn to develop applications.

Table of Contents
Part I: Get Android, Get Started1
Chapter 1:​ Introducing Android 3
Working with Android:​ The Best Parts 3
Working with Android:​ The Challenges 5
Understanding Android’s Heritage and How It Affects You 6
Understanding Android’s Future 9
What to Expect for the Rest of This Book 9
Detailing More of the Remaining Chapters 9
Chapter 2:​ Introducing Android Studio 13
Understanding What Is Meant by Integrated Development Environment, or IDE 13
The History and Provenance of Android Studio 14
Downloading the Android Studio Installer for Your Platform 14
Working with Android Studio Versions 15
Understanding How Android Studio and the Android SDK Work Together 16
Preparing for Android Studio 16
Choosing Desktop or Laptop Hardware for Android Development 16
Choosing the Operating System for Your Computer 17
Continuing with Android Studio Setup After Installation 20
Working with Alternatives to Android Studio 30
Eclipse 31
IntelliJ IDEA 31
Tools That Target Multiple Operating Systems and Mobile Platforms 32
Traditional Platform-Agnostic Development Tools 32
Chapter 3:​ Your First Android Application, Already! 33
Creating Your First Android Virtual Device 33
Creating Your First Android Application, Already! 41
Getting Your First Code Written 46
Getting Ready to Run Your Application 48
Installing (Additional) SDK Packages 50
Running Your Application 52
Chapter 4:​ Exploring Your First Project 55
Viewing the Whole Android Project Structure 55
Working with Manifests 56
Jiving with Java 58
Getting Resourceful with Resources 58
Building Everything with Gradle Files 60
Explaining the Key Android Application Logical Building Blocks 63
Activities 63
Intents 63
Services 63
Content Providers 64
Summary 64
Chapter 5:​ Android Studio In-Depth 65
Starting with the Project Explorer 65
Getting Comfortable Switching Project Explorer Views 66
Using the Project Explorer Context Menu 68
Running and Debugging with Android Studio 68
Running with Run Configs:​ A Recap 68
Running Farther with AVDs and Connected Devices 70
Debugging Instead of Running Your Code 77
Setting and Clearing Breakpoints 77
Starting Applications for Debugging 78
Stepping Through Code While Debugging 80
Attaching the Debugger 80
Viewing What You’ve Run 81
Understanding Your Build 81
Understanding Events in the Event Log 82
Understanding Logcat 83
Revisiting the SDK Manager 84
Highlighting the Other Major Features of Android Studio 86
Summary 86
Chapter 6:​ Mastering Your Entire Developer Ecosystem 87
Choosing Dedicated Developer Hardware 87
Determining Which CPU Is Right for You 88
Too Much Memory Is Never Enough! 88
Storing It All! 89
Viewing It All! 90
Connecting It All! 93
Test Handsets and Tablets 93
Option 1:​ All-Virtual Testing 94
Option 2:​ Start Virtual and Augment with Top Devices 94
Option 3:​ Buy, Buy, and Buy Some More 94
Option 4:​ Other People’s Hardware 95
Building with Build Tools 96
Update Your gradle.​properties File 96
Use the Gradle Command Line 97
Visit gradle.​org to Learn More 98
Managing Your Code with Source Control 98
Completing Your Software Repertoire 99
Summary 101
Part II: Get the Android Development Know-how103
Chapter 7:​ Introducing Java for Android Development 105
Java, Java, Everywhere 106
Android’s Java Time Warp 107
Using a JDK Installation for Learning Java 107
Your First Java Concepts in Code 109
The Key Java Building Blocks for Android Development 112
Structure of Code 113
Understanding Object-Oriented Design, Classes, and Objects 114
Working with Class Methods and Data Members 114
Summary 116
Chapter 8:​ Introducing XML for Android Development 117
Getting Started with XML 117
XML Version and Encoding 118
XML Elements 118
XML Attributes 120
XML Values 121
XML Namespaces 122
Other Parts of the XML World 123
Using XML in Your Android Applications 124
Reviewing the Android Manifest XML File 124
Using XML for Resource Definitions 125
Defining Activity Layouts with XML 128
Summary 130
Chapter 9:​ Exploring Android Concepts:​ Core UI Widgets 131
Everything Starts with View 131
Key Methods Derived from View 132
Key Attributes and Properties Derived from View 132
Introducing the Core UI Widgets in Android 132
Labeling Things with TextView 133
Buttoning the Perfect UI 138
Getting the Picture with ImageView and ImageButton 142
Editing and Inputting Text with EditText 144
Checking Out the CheckBox 147
Switching It Up with a Switch 150
Choosing Things with Radio Buttons 153
Learning Even More UI Widgets 155
Summary 155
Chapter 10:​ Exploring Android Concepts:​ Layouts and More 157
What Is Android Jetpack 157
Using Popular Layout Designs 159
Revisiting the Constraint Layout 159
Using Relative Layouts 164
Lining Up with Linear Layouts 170
Even More Layout Options 176
Table Layouts 176
Grid Layouts 177
Mastering XML-Based Layouts with Java Logic:​ The Best of Both Worlds! 177
Connecting XML Layout Definition in Java Code 178
Revisiting MyFirstApp via ButtonAgain 179
Summary 181
Chapter 11:​ Understanding Activities 183
Delving into the Android Activity Lifecycle 183
Understanding Activity Lifecycle Callback Methods 185
Appreciating the Objectives of the Activity Lifecycle 189
Managing Activity Configuration Changes 190
Working with the Default Approach to Configuration Change 190
Summary 191
Chapter 12:​ Introducing Fragments 193
Starting with the Fragment Class 193
Using Fragment-Based Design for Your Applications 194
Working with the Fragment Lifecycle 195
Reviewing the Fragment Lifecycle Callback Methods 196
Starting Simple with Fragment Lifecycle Events 198
Creating a Fragment-Based Application 198
Selecting Which Layout to Inflate 200
Coding for Fragments 201
ColorFragmentExa​mple in Action 203
Summary 206
Part III: Get Sophisticated207
Chapter 13:​ Working with Sound, Audio, and Music for Android 209
Playing Back Audio 209
Choosing Your Audio Approach 209
Working with the Media Package 210
Creating an Audio Application 211
Choosing Between Assets and Resources 211
Writing the Code for Audio Playback 212
Playing Back Audio the Simple Way 213
Coding the Java Logic for AudioPlayExample​ 214
Using Streaming for Audio Playback 217
Playing the Music Stream 220
Exploring Other Playback Options 220
Recording Audio 221
Recording Audio with MediaRecorder 221
Expanding Your Developer Audio Toolset 227
Understanding Key Audio Aspects 228
Choosing Further Audio Tools 229
Summary 231
Chapter 14:​ Working with Video and Movies for Android 233
Playing Back Video 233
Designing a VideoView-Based Layout 234
Controlling Video Playback in Your Code 236
Understanding Key Video Concepts 239
Bitrate 239
Frame Rate 240
Codecs 240
Understanding the Complex World of Video Containers and Child Codecs 241
Expanding Your Developer Video Toolset 243
Reviewing the Range of Video Editing Tools Available to You 243
Popular Open Source Video Editing Suites 244
Popular Commercial Video Editing Suites 244
Introducing HandBrake for Video Editing 245
Downloading and Installing HandBrake 245
Running and Using HandBrake 245
Going Further with Video for Android 249
Summary 249
Chapter 15:​ Introducing Notifications 251
Configuring Notifications 251
Customizing Notifications with the Notification Object 252
Adding Icons for Notifications 255
Introducing Notification Channels in API Level 26 256
Notifications in Action 257
Supporting Logic to Create the Notifications 257
Seeing Notifications from the User’s Perspective 260
Summary 264
Chapter 16:​ Exploring Device Capabilities with Calls 265
Calling the Shots 265
Specifying Telephony Support 265
Making Telephony Support Optional 266
Making Calls 266
Laying Out the CallExample Application 267
Working Logic for the CallExample Application 270
Making an ACTION_​DIAL Call 271
Making an ACTION_​CALL Call 272
Handling Incoming Calls 273
Part IV: Get Together275
Chapter 17:​ Understanding Intents, Events, and Receivers 277
Introducing Android Intents 277
Understanding Intent Behavior 278
Understanding Intent Routing 280
Including Intents in Your Manifest 280
Using Android’s Verified Links 282
Seeing Intent-Launched Activities in Action 282
Deciding on Activity Dependency 282
Creating an Intent 283
Starting the Intent-Invoked Activity 284
Introducing Receivers 288
Using Receivers When No UI Is Needed 289
Working with Receiver Limitations 289
Summary 290
Chapter 18:​ Introducing Android Services 291
Services Background 291
Using WorkManager as an Alternative to Services 292
Starting with Your Own Service 292
Implementing Your Service Class 292
Managing the Service Lifecycle via Callbacks 293
Providing Manifest Entries for Your Service 294
Service Communication 294
Service-to-Client Communication 297
Using bindService( ) Methods for All Communication 298
Intents and Broadcast Receivers 298
Use PendingIntent Objects 298
Use Messenger and Message Objects 299
Use Independent Messaging 299
Create Callbacks and Listeners 299
Use Notifications 300
Services in Action 300
Choosing the Service Design 300
Creating the Java Logic for the Service 300
Creating an Example Client to Use the Service 302
Testing the Service in Action 304
Summary 304
Chapter 19:​ Working with Files in Android 305
Using Assets and Raw Files 305
Populating Lists from Resource Files 306
Working with Files from the File System 310
Android’s File System Model 310
Permissions for Reading and Writing Files 311
Examining External Files in Action 312
What Goes into Saving and Reading Files 315
Saving and Reading Files in Action 317
Ensuring External Storage Is Available When Needed 319
Other Considerations with Android File Systems 320
Summary 322
Chapter 20:​ Working with Databases in Android 323
Working with SQLite:​ The World’s Most Popular Database! 323
Quickly Learning SQLite for Android Development 324
Creating SQLite Databases for Your Applications 325
Introducing the SQLiteExample Application 326
Creating a Database-Driven Activity 330
Choosing Query Approaches for SQLite and Android 333
Managing Results from Queries with Cursors 335
Modifying Data with Your Android Application 337
Inserting Data 337
Updating Data 339
Deleting Data 339
Using the Room Persistence Library 340
Packaging and Managing SQLite Databases for Android 340
Managing Android Storage for Database Performance 340
Packaging SQLite Databases with Your Applications 341
Choosing SQLite Management Tools to Prepare Databases for Packaging 342
Working with Built-In Tools 342
Working with Third-Party Database Tools 342
Summary 343
Index 345
About the Author
Grant AllenPhD

has worked in the technology field for over 20 years, as a CTO, entrepreneur, and emerging technology expert. After successful startup exits and a decade at Google, Grant’s focus is now mentoring and coaching startups and hi-tech companies on building great teams and great technology. He is a frequent speaker on topics such as big data, mobile ecosystems, Android, wearables, IoT, disruptive innovation, and more. Grant has a PhD in computer science based on research he performed while at Google and an MBA specializing in technology management, and he is the author of seven books on various mobile platform and data technology topics.

 
About the Technical Reviewer
Val Okafor

is a software architect with expertise in Android development and resides in sunny San Diego of California, USA. He has over 14 years of industry experience and has worked for corporations such as Sony Electronics, The Home Depot, San Diego County, and American Council on Exercise. Val earned his BSc in IT from National University, San Diego, and master’s in software engineering from Regis University, Colorado. He is the creator and principal engineer of the Pronto line of mobile apps including Pronto Journal, Pronto Invoice, and Okason Contractor App. His passion for software development goes beyond his skill and training; he also enjoys sharing his knowledge with other developers. He has taught Android development to over 5,000 students through Udemy.

 
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