Book Image

Mastering Xamarin.Forms - Second Edition

By : Ed Snider
Book Image

Mastering Xamarin.Forms - Second Edition

By: 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 API data service

Using BaseHttpService as a foundation that abstracts away the HTTP request details, we can now begin to create services that leverage it to get responses back from the API in the form of domain-specific models. Specifically, we will create a data service that can be used by the ViewModels to get the TripLogEntry objects from the backend service.

We will start off by defining an interface for the data service that can be injected into the ViewModels, ensuring that there is no strict dependency on the API, or the logic that communicates with it, continuing the pattern we put in place in Chapter 4, Platform Specific Services and Dependency Injection. To create a data service for the TripLog API, perform the following steps:

  1. Create a new interface named ITripLogDataService in the Services folder of the core library:
      public interface ITripLogDataService...