Book Image

Simplifying Android Development with Coroutines and Flows

By : Jomar Tigcal
Book Image

Simplifying Android Development with Coroutines and Flows

By: Jomar Tigcal

Overview of this book

Coroutines and flows are the new recommended way for developers to carry out asynchronous programming in Android using simple, modern, and testable code. This book will teach you how coroutines and flows work and how to use them in building Android applications, along with helping you to develop modern Android applications with asynchronous programming using real data. The book begins by showing you how to create and handle Kotlin coroutines on Android. You’ll explore asynchronous programming in Kotlin, and understand how to test Kotlin coroutines. Next, you'll learn about Kotlin flows on Android, and have a closer look at using Kotlin flows by getting to grips with handling flow cancellations and exceptions and testing the flows. By the end of this book, you'll have the skills you need to build high-quality and maintainable Android applications using coroutines and flows.
Table of Contents (11 chapters)
1
Part 1 – Kotlin Coroutines on Android
6
Part 2 – Kotlin Flows on Android

Managing coroutine timeouts

In this section, you will learn about timeouts and how you can cancel your coroutines with a timeout. Setting a fixed amount of time after which to stop asynchronous code that is running longer than expected can help you save resources and immediately notify users of any issues.

When your application is doing a background task, you may want to stop it because it is taking too long. You can manually track the time and cancel the task. Or you can use the withTimeout suspending function. With the withTimeout function, you can set your timeout in milliseconds or Duration. Once this timeout is exceeded, it will throw TimeOutCancellationException, a subclass of CancellationException. Here’s an example of how you can use withTimeout:

class MovieViewModel: ViewModel() {
    init {
        viewModelScope.launch {
            ...