Thriving in Android Development Using Kotlin: Use the newest features of the Android framework to develop production-grade apps

Cover....1

Title Page....2

Copyright and Credits....3

Dedication....4

Contributors....5

Table of Contents....8

Preface....14

Part 1: Creating WhatsPackt, a Messaging App....20

Chapter 1: Building the UI for Your Messaging App....22

Technical requirements....22

Defining the app structure and navigation....25

Modularization....25

Dependency injection....31

Navigation....32

Building the main screen....40

Adding a scaffold to the main screen....41

Adding the TopAppBar composable to the main screen....43

Adding the TabRow composable to the bottom of the main screen....44

Adding a pager....46

Adding the FloatingActionButton composable....48

Creating the conversations list....49

Modeling the conversation....50

Creating the ConversationList composable....53

Building the messages list....56

Modeling the Chat and Message models....56

Creating the MessageItem composable....57

Adding the TopAppBar and BottomRow composables....59

Adding the messages list....61

Summary....64

Chapter 2: Setting Up WhatsPackts Messaging Abilities....66

Technical requirements....67

Using a WebSocket connection....67

Why WebSockets?....67

Integrating WebSockets....69

Implementing WebSocketDataSource....72

Receiving messages in our ViewModel....78

Understanding Clean Architecture implementation....78

Creating our Clean Architecture components....81

Implementing ChatViewModel....85

Handling synchronization and errors....93

Obtaining chat screen initialization data....93

Handling errors in the WebSocket....102

Adding push notifications....104

Setting up Firebase....105

Sending the FCM token to Firebase....106

Preparing the app to receive push notifications....108

Replacing the Websocket with Firestore....113

What is Firestore?....113

Chat data structure....113

Creating a FirestoreMessagesDataSource class....116

Summary....121

Chapter 3: Backing Up Your WhatsPackt Messages....122

Technical requirements....123

Understanding Room....123

Key features of Room....123

Rooms architecture and components....124

Implementing Room in WhatsPackt....126

Adding dependencies....127

Creating the database....127

Creating entity classes....129

Creating DAOs....131

Creating a LocalMessagesDataSource data source....133

Handling two data sources in the MessagesRepository component....134

Getting to know Firebase Storage....136

How Firebase Storage works....137

Setting up Firebase Storage....138

Creating UploadMessagesUseCase....141

Scheduling WorkManager to send backups....141

Introducing the Worker class....142

Configuring the WorkRequest component....143

Creating our Worker instance....145

Setting up the WorkRequest class....146

Using Amazon S3 for storage....148

Integrating the AWS S3 SDK....149

Setting up Amazon Cognito....149

Creating an AWS S3 Storage provider and integrating it into our code....151

Summary....156

Part 2: Creating Packtagram, a Photo Media App....158

Chapter 4: Building the Packtagram UI....160

Technical requirements....161

Setting up Packtagrams modules and dependencies....161

Setting up a version catalog....161

Modularizing our app....164

Getting to know Koin....166

Setting up Koin....167

Creating the stories screen....170

Creating the newsfeed screen and its components....177

Creating the NewsFeed list....180

Creating the PostItem composable....181

Using Retrofit and Moshi to retrieve newsfeed information....191

Adding the Retrofit and Moshi dependencies....192

Creating the data source for the newsfeed....194

Creating the repository....195

Creating the GetTheNewsFeedUseCase....196

Integrating the use case into our ViewModel....198

Implementing pagination in the newsfeed....199

Summary....203

Chapter 5: Creating a Photo Editor Using CameraX....204

Technical requirements....205

Getting to know CameraX....205

The evolution of camera libraries in Android....205

The importance and advantages of CameraX....205

Setting up CameraX....206

Learning about CameraXs core concepts....208

Integrating CameraX into our Packtagram app....216

Setting up the permissions checker with Accompanist....216

Creating our own CameraPreview....221

Adding photo-saving functionality....222

Adding photo-editing functionalities....232

Adding filters....233

Adding a text overlay....235

Using ML to categorize photos and generate hashtags....241

Summary....246

Chapter 6: Adding Video and Editing Functionality to Packtagram....248

Technical requirements....249

Adding video functionality to our app....249

Getting to know FFmpeg....256

The components of FFmpeg....256

Key features of FFmpeg....256

Integrating mobile-ffmpeg into our project....257

Understanding the FFmpeg command-line syntax....258

Advanced syntax and options in FFmpeg....261

Using mobile-ffmpeg to execute FFmpeg commands....265

Adding a caption to the video with FFmpeg....267

Adding a filter to a video with FFmpeg....272

Uploading the video....277

Summary....280

Part 3: Creating Packtflix, a Video Media App....282

Chapter 7: Starting a Video Streaming App and Adding Authentication....284

Technical requirements....285

Creating the apps structure and modules....285

Setting up the dependency injection framework....288

Building the login screen....289

Authenticating the apps users....296

Creating the user model....297

Using Retrofit to get the authorization token....297

Using DataStore to store the token....300

Sending the authorization token in requests....305

Creating your movie list....308

Building the models....308

Building the MoviesScreen composable....309

Making the movie and series detail screen....318

Creating the detail models....318

Building the DetailScreen....319

Summary....328

Chapter 8: Adding Media Playback to Packtflix with ExoPlayer....330

Technical requirements....331

Reviewing Androids media options....331

Learning about the MediaPlayer API....331

Learning about VideoView....334

Understanding the basics of ExoPlayer....336

Exploring ExoPlayers architecture....337

Integrating ExoPlayer into our project....342

Creating the video playback user interface....343

Building PlaybackScreen and its composables....343

Making the controls disappear when playing the content....348

Playing video using ExoPlayer....350

Creating PlaybackActivity....350

Creating PlaybackViewModel....351

Connecting the controls with ExoPlayer....355

Implementing the video controls in PlaybackViewModel....362

Adding subtitles to the video player....365

Summary....368

Chapter 9: Extending Video Playback in Your Packtflix App....370

Technical requirements....370

Getting to know the PiP API....371

PiP requirements....371

Entering and exiting PiP mode programmatically....372

Using PiP to continue playback in the background....373

Implementing PiP....374

Understanding how to add actions to the PiP mode....376

Adding actions to the PiP mode....377

Getting to know MediaRouter....382

Setting up MediaRouter....383

Discovering media routes....384

Connecting to Google Chromecast devices....389

Summary....395

Index....396

Other Books You May Enjoy....1

Build a range of Android applications such as a messaging app, a photo editor, and a video streaming platform that address common real-world issues such as authentication, connecting to synchronous and asynchronous remote sources, rendering complex UIs with Jetpack Compose, and more with seasoned Android GDE, Gema Socorro Rodriguez

Key Features

• Understand complex concepts in a coherent way by solving challenging real-world problems and developing three practical projects
• Use the latest features of libraries in Jetpack Compose, Room, CameraX, ExoPlayer, and more
• Leverage best practices for UI creation, app structure, data handling, and lifecycle management
• Purchase of the print or Kindle book includes a free PDF eBook

Book Description

Finding resources on creating apps with the Android framework and Kotlin is easy, but discovering content that addresses the common challenges faced by app developers is difficult. This book is designed to bridge that gap and equip you with the skills to tackle everyday problems in Android development.

You'll get hands on with Android development by building an app similar to WhatsApp. Next, you'll learn how to process asynchronous messages reactively, render them using Jetpack Compose, and advance to creating and uploading a backup of these messages. As you progress, you'll develop Packtagram, an app inspired by Instagram, focused on advanced photo-editing capabilities using the latest CameraX libraries. Finally, you'll build your own Netflix-like app, integrating video playback functionality with ExoPlayer for both foreground and background operations, and enabling casting to other devices.

By the end of this book, you'll have crafted three fully functional projects across multiple platforms and gained the expertise to solve the most common challenges in Android development confidently.

What you will learn

• Create complex UIs with Jetpack Compose
• Structure and modularize apps with a focus on further scaling
• Connect your app to synchronous and asynchronous remote sources
• Store and cache information and manage the lifecycle of this data
• Execute periodic tasks using WorkManager
• Capture and edit photos and videos using CameraX
• Authenticate your users securely
• Play videos in the foreground and background and cast them to other devices

Who this book is for

If you're a mid-level Android engineer, this book is for you as it will not only teach you how to solve issues that occur in real-world apps but also benefit you in your day-to-day work. This book will also help junior engineers who want to get exposed to complex problems and explore best practices to solve them. A basic understanding of Android and Kotlin concepts such as views, activities, lifecycle, and Kotlin coroutines will be useful to get the most out of this book.