Painless Networking with Retrofit

The content of this book is completely updated to Retrofit 2.5!

Every modern Android app needs to connect to at least one private or public API. Interacting with services can be difficult due to the extreme variety of request and response formats. Depending on the API, you’ll need to change your request payloads, authentication, data formats, and much more.

Retrofit: a type-safe HTTP client for Android and Java

Retrofit handles all of the complicated and repetitive parts of network implementations for you. It hides the entire network layer, from creating a connection to processing the handling on a separate thread, from you. Retrofit even does the mapping of the requests and responses to Java objects for you (e.g., creating a JSON payload from your passed List<User>). You only need to describe what and how you want to send or receive it.

This awesomeness comes at a cost: an initial learning curve. Retrofit might look a little more complicated at the beginning, but pays off multiple times in the long run.

If you’re thinking about using Retrofit, or haven’t developed a deep knowledge of it yet, you’ll benefit from this book. We’ve created this book with the vision of being the ultimate guide to understanding Retrofit. After working through this book, you’ll be able to connect to new APIs and services within minutes.

You can find a Retrofit tutorial series on our website and our free video tutorial series on YouTube, where we describe some elements of Retrofit. The book extends and connects these tutorials into one common thread that guides you through all important aspects of Retrofit. The chapters are structured in a way that rewards a linear reading. Retrofit rookies can and should read it cover to cover. Experienced Retrofit developers can jump to specific sections for guides on how to solve their specific problem.

What Topics Are Covered in This Book?

The list below provides a comprehensive overview of covered topics in the book.

• Introduction to Retrofit
• Quick Start Guide to jump right into Retrofit
• Creating a sustainable Android REST client
• Extensive manipulation and customization of requests (e.g., query and path parameters, form-urlencoding, synchronous vs. asynchronous)
• Cancel, analyze and re-use requests
• Comprehensive overview of response converters and data mapping with plenty practical examples of applied (custom) converters
• Implementing and handling authentication (basic, token, OAuth, hawk) in a smart way
• File uploads, including multiple and dynamic amounts of files (optionally with progress updates)
• File download (optionally with progress updates)
• Detailed chapter on implementing pagination
• Introduction and example of possible ways to deal with errors in a clean way
• Debug requests and responses using three logging tools (OkHttp, Stetho, Android Studio Profiler)
• Fundamentals for mocking server responses
• Entire chapter on practical examples of custom converters dealing with specific scenarios
• Detailed introduction to call adapters, including custom implementations
• Extensive chapter on implementing response caching with Retrofit
• Example for an offline mode based on cached server responses
• A chapter with practical tips & tricks (including crawling websites with Retrofit)
• App release preparation including ProGuard configuration

Additionally to the regular content we provide an appendix with three sections:

• Upgrade guide from Retrofit 1.9 to 2.0
• Java basics for Retrofit
• Network basics for developers, who just started interacting with APIs

Who Is This Book For?

In short: this book is for you. We believe that every developer reading this book will take away new ideas on how to optimize their Android apps in the sense of interacting with APIs or web services using Retrofit. You’ll recognize goodies that are applicable for the projects you’re working on.

This book is for Android developers, who want to receive a substantial overview and reference book on Retrofit. You’ll benefit from clearly recognizable code examples related to your daily work with Retrofit.

Rookie

If you’re just starting out with Retrofit (or coming from another HTTP library like Android Asynchronous Http Client or Volley) this book will show you all important parts on how to create sustainable REST clients on Android. The provided code snippets let you jumpstart and create your first successful API client within minutes!

Expert

If you’ve already worked with Retrofit, you’ll profit from our extensive code snippets and apply the learnings to your existing code base. Additionally, the book illustrates various use cases for different functionalities and setups like authentication against different backends, request composition, file uploads and downloads, and much more!

One focus of this book is not only to implement the requirements, but also do so in a clean way. We’ve seen way to many complicated and messy usages of Retrofit. We focus on providing code samples which adhere to clean code standards. We avoid any unnecessary duplication at all costs. This has the side effect of some extra app performance gains by efficient Java object handling.

Source Code Samples

With the purchase of this book, you benefit from the sample project that awaits your download within the extras section on Leanpub. The sample project is an Android project based on gradle. You can directly touch and use classes that are only illustrated in excerpts within this book.

Check your Leanpub Library and select Retrofit: Love working with APIs on Android to download the sample code base.

Continuous Updates

We’ve published the first version of this Retrofit book in July 2015. Since this initial release we’ve extended and updated the book more than a dozen times. Once you buy the book, you get all future updates for free. Even if it’s a huge Retrofit update, for example from version 1.9 to 2.0. With every new release of Retrofit we’ll evaluate the entire book content and update it accordingly.

Of course, we’re listening to your feedback and add new sections and even chapters, if it can be useful to all readers. If you still have a question after reading this book, let us know and we might be able to help!

Still Unsure?

If you’re still on the fence if this book helps you, checkout the sample or, even better, use Leanpub’s (and our) happiness guarantee. Try this book out and if you don’t think this book provides enough value, you can refund your money within 45 days with no questions asked. You don’t have any risk in testing this book, which saves you hours of headaches and makes your Android app code so much cleaner.

Final Note: Retrofit Book for Version 1.9

The current version of this book is fully focused on Retrofit 2.x, no hint or code snippet that points to Retrofit 1. If you’re interested in the first version of the book that based on Retrofit 1, please visit this book’s extras page on Leanpub. As a reader of this book, the first version is also available for you!

Nowadays apps need to be polished to be successful. Picasso offers an easy way to add images to your app without much hassle. If your Android app uses images, this book will save you a ton of time researching and avoid long evenings of bug fixes. If you value your time, this is something for you.

We cover every functionality of the latest Picasso release. Of course, we'll update the book with future releases.

This book is for beginners and advanced readers as well. We’ll walk you through each topic with direct reference to code examples. Once you’ve worked through this book, you’ll have an extensive knowledge of image loading on Android with Picasso.

The content of this book is completely updated to Picasso 2.5.2! 

What Topics are Covered in this Book?

The list below provides a comprehensive overview of covered topics within the book.

• Introduction to Picasso
• Loading and Displaying Images
• Placeholders, Resizing and Optimized Request Management
• Image Rotation and Transformations
• Caching Is Critical
• Customizing Picasso
• Practical Code Examples
• App Release Preparations
• Appendix: Use & Migrate to Picasso 3.0

Who Is This Book For?

This book is for Android developers who want to get an substantial overview and reference book of Picasso. You’ll benefit from the clearly recognizable code examples in regard to your daily work with Picasso.

Rookie

If you’re just starting out with Picasso (or coming from any other image loading library like Glide) this book will show you all important parts on how to work with images. The provided code snippets let you jumpstart and create an image-rich app within minutes.

Expert

You already worked with Picasso before? You’ll profit from our extensive code snippets and can improve your existing code base. Additionally, the book illustrates various optimizations for an even better user experience.

Code Samples

Every code snippet in the book has been tested. The example project is provided as an extra download. We recommend to download it and check the full code base as you move through the book. We try to keep the code snippets in the book as short as possible. If more context is necessary, the example app's code provides it.

Free Lifetime Updates

We've released this book on Picasso in October 2015 and it's still getting updates. We've been updating the book with every minor Picasso release. We also added new chapters based on reader feedback. The price of the eBook went up along with its value. The first buyers of our products always get the best deal and the lowest price!

• We don't do sales with discounts, so don't wait for it
• Our prices only go up
• Buy now and get a voice for future improvements

Not Convinced Yet?

Fair enough! If you’re still on the fence if this book helps you, checkout the sample or, even better, use Leanpub’s (and our) happiness guarantee. Try this book out and if you don’t think this book provides enough value, you can refund your money within 45 days with no questions asked. You don’t have any risk in testing this book, which saves you hours of headaches and increases your app's quality and user experience.

In order to be competitive in today's Google Play environment, your app needs to be polished. Images need to be used consistently and loaded smoothly. If your Android app uses images, this book will save you a ton of time researching and avoid stressful evenings of bug fixes. If you value your time, this is something for you.

We cover every feature of Glide! This book is for beginners and advanced readers as well. We’ll walk you through each topic with direct reference to code examples. Once you’ve worked through this book, you’ll be the expert of image loading on Android with Glide.

The content of this book is completely updated to Glide 4.8.0! The previous book version for Glide 3.x is included.

What Topics are Covered in this Book?

The list below provides a comprehensive overview of covered topicS within the book.

• Introduction to Glide
• Loading Images, Gifs & Local Video Thumbnails
• Image Display, Adapter Usage (ListView, RecyclerView, CardView) & Placeholders
• Request Options & Generated API
• Image Resizing & Thumbnails
• Caching & Request Priorities
• Callbacks With Glide Targets
• Exception Handling and Debugging (Android Studio Profiler, Stetho)
• Image Rotation and Glide Transformations
• Glide Animations
• Customizing Glide with Glide Modules (Custom SSL, Custom Network Timeouts, ...)
• App Release Preparations
• Upgrade Guide from Glide 3.x to Glide 4

Who Is This Book For?

This book is for Android developers who want to get an substantial overview and reference book of Glide. You’ll benefit from the clearly recognizable code examples in regard to your daily work with Glide.

Rookie

If you’re just starting out with Glide (or coming from any other image loading library like Picasso) this book will show you all important parts on how to work with images. The provided code snippets let you jump-start and create an image-rich app within minutes.

Expert

You already worked with Glide before? You’ll profit from our extensive code snippets and can improve your existing code base. Additionally, the book illustrates various optimizations for an even better user experience.

Code Samples

Every code snippet in the book has been tested. The example project is provided for free as an extra download. We recommend to download it from Leanpub's book extra section and check the full code base as you move through the book. We try to keep the code snippets in the book as short as possible. If more context is necessary, the example app's code provides it.

Free Lifetime Updates

We've released this book on Glide in October 2015 and it's still getting updates. We've been updating the book with every minor Glide release. The price of the eBook went up along with its value. The first buyers of our products always get the best deal and the lowest price!

• We don't do sales with discounts, so don't wait for it
• Our prices only go up
• Buy now and get a voice for future improvements

Not Convinced Yet?

Fair enough! If you’re still on the fence if this book helps you, checkout the sample or, even better, use Leanpub’s (and our) happiness guarantee. Try this book out and if you don’t think this book provides enough value, you can refund your money within 45 days with no questions asked. You don’t have any risk in testing this book, which saves you hours of headaches and increases your app's quality and user experience.

Learn Every Detail About Gson

Every modern Java application will need to do some Java-JSON parsing in their application life cycle. Gson is the most commonly used library to do the Java-JSON serialization and deserialization automatically.

Data parsing and mapping is complex. Even though Gson makes things quite simple, there are a lot of details that can trip your development up. If it's crazy data structures, weird variable names or complex dynamic data, you can lose a lot of time on something that should be done in minutes. Gson solves most problems in just a few lines. You just need to know the solutions!

This book includes an extensive introduction to Gson's features. We recommend to read it before you even have to use Gson for the first time. But even if you're already an avid user of Gson and stuck at a problem, we're confident we'll solve your problem.

Use our extensive bundle to learn about:

• Introduction to JSON & JSON-Java mapping
• Quick start to jump right into Gson
• Mapping of any Java type
• Deep dive into Gson's configuration options
• Practical examples of Gson customization
• Even advanced topics (Streaming, Generics, ...) are covered
• Necessary ProGuard configuration for Android app releases

Additionally, you'll get an extensive appendix:

• Combining a customized Gson with Retrofit 2
• Overview over common mistakes
• Exploration of Gson alternatives

Who Is This Book For?

This book is for Android or Java developers who want to get a substantial overview and reference book for Gson. You’ll benefit from the clearly recognizable code examples in regard to your daily work with Gson.

Rookie

If you’re just starting out with Gson (or coming from any other Java-JSON library like Jackson databind) this book will show you all important parts on how to work with Gson. The provided code snippets let you jumpstart and create the first mapping within minutes.

Expert

You already worked with Gson before? You’ll profit from our extensive code snippets and can improve your existing code base. Additionally, the book illustrates various optimizations for an even better performance.

Code Samples

Every code snippet in the book has been tested. We provide our test project as a leanpub extra. Feel free to download it and check the full code base as you move through the book. We try to keep the code snippets in the book as short as possible. If more context is necessary, the code examples should provide it.

Workbook

For the first time, we provide additional separated resources besides our book. The workbook gives you a chance to implement everything you'll learn in this book yourself. In our experience actually using a library like Gson helps to reinforce the newly gained knowledge. Thus, we've designed the workbook, which gives you a guided playground to experiment and learn the features of Gson.

We’ve published a book on Gson, which is designed to give you an in-depth learning experience. We specifically tailored it for every Java application and not just Retrofit developers.

The idea of this workbook is three-fold:

• Give the readers of the Gson book a specific playground to practice the learned theory

• Let experienced Gson users test their knowledge

• Offer a way to learn Gson for people who don’t like reading technical books and rather experiment on their own.

We cover a lot of aspect of Gson in this workbook. We’ve roughly 40 tasks for you. If you wish, you can use our project framework. Automated unit tests will tell you if your implementation for that particular task was correct. Of course, every task comes with a sample solution.

What Topics Are Covered in This Workbook?

The list below provides a comprehensive overview of covered topics within the book.

• Introduction to JSON & JSON-Java mapping

• Mapping of various Java data type

• Dive into Gson’s configuration & customization options

• Multiple tasks on Custom Serializer & Custom Deserializer

• Four Advanced topics (Streaming, Low-Level-Parsing, …)