Android Application Development All-in-One For Dummies

CONQUER THE WORLD OF ANDROID APP DEVELOPMENT

Android has taken over the mobile and TV markets and become unstoppable! Android offers a vast stage for developers to serve millions—and rake in the profits—with diverse and wide-ranging app ideas. Whether you're a raw recruit or a veteran programmer, you can get in on the action and become a master of the Android programming universe with the new edition of Android Application Development For Dummies All-in-One. In addition to receiving guidance on mobile and TV development, you'll find overviews of native code, watch, car, Android wear, and other device development.

This friendly, easy-to-follow book kicks off by offering a fundamental understanding of Android's major technical ideas, including functional programming techniques. It moves on to show you how to work effectively in Studio, program cool new features, and test your app to make sure it's ready to release to a waiting world. You'll also have an opportunity to brush up on your Kotlin and develop your marketing savvy. There are millions of potential customers out there, and you want to stand out from the crowd!

* Understand new features and enhancements
* Get development best-practices
* Know your Android hardware
* Access online materials

With a market share like Android's, the stakes couldn't be higher. Android Application Development For Dummies All-in-One levels the field and gives you the tools you need to take on the world.

BARRY BURD, PHD, is a veteran author and educator. At the University of Illinois, he was five times elected to the university-wide List of Teachers Ranked as Excellent by their Students. He has written several books on Java and Android development. JOHN PAUL MUELLER has produced 115 books and more than 600 articles on topics ranging from functional programming techniques to application development using C++. 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

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