Book Image

Learn Spring for Android Application Development

By : S. M. Mohi Us Sunnat, Igor Kucherenko
Book Image

Learn Spring for Android Application Development

By: S. M. Mohi Us Sunnat, Igor Kucherenko

Overview of this book

As the new official language for Android, Kotlin is attracting new as well as existing Android developers. As most developers are still working with Java and want to switch to Kotlin, they find a combination of these two appealing. This book addresses this interest by bringing together Spring, a widely used Java SE framework for building enterprise-grade applications, and Kotlin. Learn Spring for Android Application Development will guide you in leveraging some of the powerful modules of the Spring Framework to build lightweight and robust Android apps using Kotlin. You will work with various modules, such as Spring AOP, Dependency Injection, and Inversion of Control, to develop applications with better dependency management. You’ll also explore other modules of the Spring Framework, such as Spring MVC, Spring Boot, and Spring Security. Each chapter has practice exercises at the end for you to assess your learning. By the end of the book, you will be fully equipped to develop Android applications with Spring technologies.
Table of Contents (13 chapters)

Callback hell

One of the main reasons that you should use coroutines is to avoid callback hell.

This section will cover the following topics:

  • What is a callback?
  • Wrapping callbacks

What is a callback?

A callback is a pattern that is used to retrieve the results of an asynchronous task. This approach assumes that we pass a reference to a function that should be invoked when an asynchronous operation is done.

By synchronous operations, we mean that the tasks are executed one after another. The asynchronous approach assumes that several tasks can be performed in parallel.

The loadImage function in the following example code uses a callback to return the result:

fun loadImage(callback: (Image) -> Unit) {
executor.submit...