Book Image

Mastering Xamarin.Forms - Second Edition

By : Hernandez, Ed Snider
Book Image

Mastering Xamarin.Forms - Second Edition

By: Hernandez, Ed Snider

Overview of this book

Discover how to extend and build upon the components of the Xamarin.Forms toolkit to develop effective, robust mobile app architecture. Starting with an app built with the basics of the Xamarin.Forms toolkit, we'll go step by step through several advanced topics to create a solution architecture rich with the benefits of good design patterns and best practices. We'll start by introducing a core separation between the app's user interface and the app's business logic by applying the MVVM pattern and data-binding. Then we will focus on building out a layer of plugin-like services that handle platform-specific utilities such as navigation and geo-location, as well as how to loosely use these services in the app with inversion of control and dependency injection. Next we'll connect the app to a live web-based API and set up offline synchronization. Then, we'll dive into testing the app logic through unit tests. Finally, we will setup Visual Studio App Center to automate building, testing, distributing and monitoring the app.
Table of Contents (11 chapters)

Creating an authentication service

Now that we have enabled our backend service with Facebook authentication, the app as it is from the previous chapter will fail to load content. In this section, we will update the app to authenticate users with Facebook via OAuth and obtain an access token from Azure that can be used in subsequent API calls by the TripLogApiDataService.

As in the previous chapter, instead of using the Azure Mobile Apps client SDK, we will directly call the REST endpoints behind the SDK to better understand the approach to authenticate to an API in a more generic way. In order to do this, we will first make an OAuth call to Facebook, obtaining a Facebook token. We will then pass that token to an Azure Mobile App Service endpoint, where it is validated using the Facebook app ID and secret that were added to the service's configuration in Azure to finally...