Table of Contents
Introduction 1 How to Use This Book 1
Conventions Used in This Book 2
Foolish Assumptions 2
Icons Used in This Book 3
Beyond the Book 4
Where to Go from Here 4
Book 1: Getting Started with Android Application Development 5
Chapter 1: All about Android 7
The Consumer Perspective 8
The Versions of Android 9
The Developer Perspective 12
Java and Kotlin 12
XML 14
Linux 16
The Business Perspective 18
Chapter 2: Installing the Software Tools 19
Setting Up the Software 20
Considering the requirements 20
Downloading the software 21
Installing Android Studio 23
Installing offline tools 25
Launching the Android Studio IDE 28
In Windows 29
On a Mac 29
In Linux 30
In Chrome OS 30
Using the Android Studio Setup Wizard 30
Fattening Up the Android SDK 32
The more things stay the same, the more they change 32
Installing new versions (and older versions) of Android 33
Creating an Android virtual device 35
A third-party emulator 39
Chapter 3: Creating an Android App 43
Creating Your First App 43
Starting the IDE and creating your first app 45
Launching your first app 50
Running Your App 52
You Can Download All the Code 55
Troubleshooting Common IDE Errors 58
Error message: Failed to find target 58
Error running ‘app’: No target device found 58
Error message: Android Virtual Device may be incompatible with your configuration 58
You lose contact with the Android Debug Bridge (ADB) 59
You don’t like whatever AVD opens automatically 59
The emulator stalls during startup 60
Error message: The user data image is used by another emulator 61
Error message: Unknown virtual device name 63
The emulator displays a “process isn’t responding” dialog box 63
Changes to your app don’t appear in the emulator 64
Testing Apps on a Real Device 64
Chapter 4: Examining a Basic Android App 67
A Project’s Files 68
The MainActivity.kt file 71
The onCreate() method 72
Using other templates 73
The res Branch 76
The res/drawable branch 77
The res/layout branch 77
The res/menu branch 78
The res/mipmap branch 79
The res/values branch 80
Other Files in an Android Project 82
The build.gradle file 82
The AndroidManifest.xml file 85
The R.java file 87
The assets folder 89
The android.jar archive 90
The APK file 91
What Did I Agree To? 93
What’s in a name? 93
Choosing a language 95
Your app’s API levels 95
Chapter 5: Conjuring and Embellishing an Android App 101
Dragging, Dropping, and Otherwise Tweaking an App 102
Creating the “look” 102
Coding the behavior 112
A Bit of Debugging 118
Try it! 118
Discovering the secrets of Logcat 123
Using the debugger 126
Chapter 6: Improving Your App 131
Improving the Layout 131
Changing the layout 132
Creating a reusable layout 139
Reusing a layout 142
Starting Another Activity 145
Localizing Your App 151
Responding to Check Box Events 155
Displaying Images 157
Sending in Your Order 162
Book 2: Android Background Material 167
Chapter 1: Using Android Studio 169
Good to Know versus Need to Know 170
Getting a Feel for the Big Picture 171
The main window 173
Viewing modes 179
The Designer tool 181
Discovering What You Can Do 184
Finding things 185
Fixing code 190
Refactoring 199
Chapter 2: Kotlin for Java Programmers 203
Using Kotlin or Java for Development 204
Defining the Java Issues That Kotlin Fixes 207
Improving control over null references 207
Removing raw data types 210
Using invariant arrays 210
Working with proper function types 212
Getting rid of the checked exceptions 213
Nothing’s Perfect: Kotlin is Missing Features, Too 214
Considering primitive types that are not classes 214
Losing static members 214
Eliminating non-private fields 215
Reducing confusion by eliminating wildcard-types 216
Abandoning the ternary-operator a—b : c 217
Looking at What Kotlin Adds to the Picture 218
Considering higher order functions and lambdas 218
Refining object orientation using extension functions 218
Relying on smart casts 219
Employing string templates 220
Understanding primary constructors 221
Implementing first-class delegation 221
Using ranges of values 223
Creating data classes 224
Overloading operators 224
Developing asynchronous code using coroutines 225
Chapter 3: Kotlin for Everyone 227
Moving from Development to Execution with Kotlin 228
What is a compiler? 228
Understanding native code compiler or interpreter issues 230
Considering the Android Runtime (ART) 231
Grasping Kotlin Code 235
Nearly everything begins with an expression 236
The Kotlin class 238
Classes and objects 239
Kotlin types 240
Performing casts 245
The Kotlin function 249
Objects and their constructors 252
Classes grow on trees 254
The Kotlin package 255
Considering Kotlin visibility rules 257
Defying your parent 258
Kotlin comments 259
Chapter 4: What Kotlin Does (and When) 261
Making Decisions (Kotlin if Statements) 261
Testing for equality 264
Choosing among many alternatives (Kotlin when statements) 266
Repeating Instructions Over and Over Again 269
Kotlin while statements 269
Kotlin do statements 271
Arrays in Kotlin 273
Kotlin’s for statements 277
Looping using Kotlin recursion 281
Working with break and continue 283
Jumping Away from Trouble 284
Working with Kotlin Collections 286
Considering the collection types 287
Differentiating between read-only and mutable collections 289
Chapter 5: Object-Oriented Programming in Kotlin 291
Static Fields and Methods 291
Interfaces and Callbacks 294
Event handling and callbacks 299
An object remembers who created it 302
A less wordy way to implement an interface 303
Classes That Must (and Must Not) Be Extended 305
The need to override 306
Java’s final classes 306
Kotlin’s open classes 307
Kotlin extensions 307
Abstract classes 308
Inner Classes 310
Named inner classes 310
Anonymous inner classes 312
Chapter 6: Functional Programming in Kotlin 315
Defining Functional Programming 316
Differences from other programming paradigms 316
Understanding its goals 317
Understanding Pure and Impure Languages 318
Using the pure approach 318
Using the impure approach 320
Comparing the Functional Paradigm 320
Using Kotlin for Functional Programming Needs 322
Defining the Role of State 323
Using Recursion to Perform Calculations 324
Relying on standard recursion 324
Relying on tail recursion 326
Using Function Types 327
Understanding Function Literals 329
Lambda expressions 329
Anonymous functions 330
Defining the Function Types 331
Comprehensions 331
Receivers 332
Inline 334
Utility 335
Using Functional Programming for Android Apps 336
Chapter 7: A <brief> Look at XML 339
XML Isn’t Ordinary Text 340
Of tags and elements 340
Other things you find in an XML document 348
What’s in a Namespace? 350
The package attribute 353
The style attribute 354
Book 3: The Building Blocks 357
Chapter 1: Getting an Overview of Jetpack 359
Understanding the Benefits of Jetpack 360
Eliminating boilerplate code 360
Managing background tasks 361
Navigating between activities and fragments 362
Managing memory 364
Performing configuration changes 365
Considering the Jetpack Components 366
Foundation 367
Architecture 368
Behavior 370
UI 372
Getting an Overview of the AndroidX Package 373
Working with Lifecycle-Aware Components 374
Focusing on activities 375
Understanding events and states 376
Chapter 2: Building a Foundation for Your App 377
Working with Android KTX 378
Getting a feel for KTX features 378
Using KTX in your project 381
Considering the modules 382
Addressing Security Issues 389
Benchmarking Your Application 392
Removing barriers to correct results 393
Creating a test app 394
Profiling your app 397
Tracing your app 398
Checking for benchmarking module support 400
Benchmarking the app 401
Testing Application Functionality 403
Chapter 3: Creating an Architecture 405
Managing Application Activities 405
Defining an activity 406
Getting an overview of intent filters 407
Considering the activity lifecycle 407
Understanding the backstack 409
Working with fragments 412
Considering the fragment lifecycle 416
Seeing activities and fragments in action 417
Providing for Navigational Needs 433
Creating the navigational graph 434
Adding a NavHostFragment to your activity 437
Adding destinations 438
Creating links between destinations 440
Creating the required linkages 442
Performing Background Tasks Using WorkManager 446
Chapter 4: Defining an App’s Behavior 451
Working with Notifications 452
Understanding what notifications do 452
Anatomy of a notification 454
Assigning a channel to your notification 456
Setting the notification importance 457
Considering the notification types 458
Relying on notification updates 459
Do Not Disturb mode 460
Creating a notification 460
Getting Permission 466
Considering permission use 467
Configuring permissions in AndroidManifest.xml 468
Complying with User Preferences 469
Deciding on a preference set 470
Setting preferences using the Preference Library 472
Working with MediaPlayer 481
Adding Camera Support Using CameraX 484
Sharing with Others 487
Performing simple share actions with other apps 487
Using Slices 488
Chapter 5: Interacting with the Users 491
Creating a Great Layout 492
Defining the View and ViewGroup elements 492
Creating a layout using XML 493
Modifying a layout at runtime 497
Considering the common layouts 498
Working with adapters 499
Debugging your layout 500
Employing Color and Texture 502
Working with styles and themes 503
Creating a palette 509
Using swatches to create color schemes 510
Using Animations and Transitions 510
Understanding the need for animations 511
Animating graphics 511
Communicating with Emoji 514
Keyboard emoji support 515
Using the cut-and-paste method on standard controls 516
Using the AndroidX approach 517
Book 4: Programming Cool Phone Features 521
Chapter 1: Hungry Burds: A Simple Android Game 523
Introducing the Hungry Burds Game 523
The Hungry Burds Project’s Files 526
The Main Activity 528
The Code, All the Code, and Nothing But the Code 530
Setting Up the Game 535
Declaring properties 535
The onCreate Method 537
Displaying a Burd 538
Creating random values 538
Creating a Burd 539
Placing a Burd on the constraint layout 540
Animating a Burd 542
Handling a Touch Event 544
Finishing Up 546
Chapter 2: An Android Social Media App 547
Setting Things Up on Facebook’s Developer Site 548
A Minimal Facebook App 549
The build.gradle file 550
The manifest file 550
A Bare-Bones Main Activity 551
Enriching the Minimal App 555
Working with a radio group 559
Controlling the web view 562
Who tests your Facebook app? 563
Chapter 3: Going Native 567
The Native Development Kit 567
Understanding why you need the NDK 568
Knowing what you get 569
Getting the NDK 570
Creating an Application 573
Starting with the template 573
Seeing the essential project differences 575
Considering the build.gradle (Module: app) differences 577
Understanding the default template differences 580
Getting an overview of the C++ file 582
Seeing the result 583
Book 5: Apps for Tablets, Watches, TV Sets, and Cars 585
Chapter 1: Apps for Tablets 587
Gaining Perspective 588
Creating the right devices 589
Running code on multiple devices 593
Copying the project 594
Seeing presentation differences 596
Developing a Nested Navigational Graph 603
Understanding the uses for nested navigational graphs 603
Developing an app design 604
Considering the content needs 608
Creating a Responsive App 612
Chapter 2: Developing for Android Wear 615
Seeing Where Wearables Are Used 615
Setting Up Your Testing Environment 617
Creating the project 617
Configuring a wearable device emulator 620
Other testing configurations 624
Wearable Apps: What’s the Big Deal? 625
Case Study: A Watch Face 626
Defining the watch face project 627
Testing the watch face app 628
Dissecting the skeletal watch face project 631
Enhancing the skeletal watch face project 634
Chapter 3: Developing for Android TV 637
Getting Started 638
Running the Skeletal App 641
Dissecting the TV App 644
Adding to the standard AndroidManifest.xml 644
Looking into build.gradle (Module: app) 645
Defining a layout 646
The adapter and the presenter 647
Using the Adapter class 648
Using the Presenter class 650
Chapter 4: Developing for Android Auto 653
Checking Auto Compatibility 654
Choosing the Google Play Services 656
Considering Notification Limits 658
Creating an Emulator 660
Configuring your car for development 661
Defining an emulator 662
Developing an Android Auto App 670
Creating the project 670
Viewing the project configuration 672
Performing required configuration tasks 674
Touring the Media Service app 675
Book 6: The Job Isn’t Done Until 679
Chapter 1: Publishing Your App to the Google Play Store 681
Creating a Google Play Developer Account 681
Preparing Your Code 682
Un-testing the app 683
Choosing Android versions 683
Setting your app’s own version code and version name 684
Choosing a package name 685
Preparing Graphic Assets for the Play Store 685
Creating an icon 686
Creating screenshots 688
Providing other visual assets 690
Creating a Publishable File 691
Differences among builds 692
Creating the release build 697
Running a new APK file 702
Running the app in a new AAB file 703
Another way to build and run an AAB file 705
Publishing Your App 708
The App Releases page 708
The Store Listing page 710
The App Signing page 711
Other pages 711
Leave No Stone Unturned 714
Publishing Elsewhere 714
The Amazon Appstore 714
Other venues 715
Chapter 2: Monetizing and Marketing Your App 717
Choosing a Revenue Model 718
Charging for your app 719
Offering an extended free trial 723
Freemium apps 724
Selling things with your app 726
Subscription pricing 729
Earning revenue from advertising 729
Variations on in-app advertising 731
Donationware 732
Offering your app for free 732
Getting paid to develop apps for others 732
Marketing Your Application 733
Brick Breaker Master: An App Marketing Case Study 734
Chapter 3: Creating Public Support for Your App 739
Obtaining Support through Patreon 740
Discovering that patronage isn’t new 740
Considering crowdfunding 741
Defining why you should use crowdfunding 741
Understanding the development angle 742
Determining the trade-offs 744
Developing Your Own Distribution Stream 744
Creating podcasts 744
Developing YouTube videos 746
Employing social media 748
Answering questions 750
Taking the Personal Approach 750
Creating a blog 751
Answering your email 752
Considering App Store Alternatives 754
Getting Awards 756
Looking for awards in all the right places 757
Strutting your stuff 757
Index 759
