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)

Value converters

Value converters form an important concept in data binding because they allow you to customize the appearance of a data property at the time of binding. If you have done any WPF or Windows app development, you will probably be familiar with how value converters work. Xamarin.Forms provides an almost identical value converter interface as part of its API.

One of the biggest benefits of a value converter is that it prevents you from having to add a bunch of getter properties to your data model to adjust how things are displayed. For example, imagine you have a status property on your model, and you want to change the font color of the status when it is displayed based on its value. You could add a getter property to your model that returns a color based on the current value of the status property. This approach works, but it clutters the model and also potentially...