Book Image

Mastering Xamarin.Forms

By : Ed Snider
Book Image

Mastering Xamarin.Forms

By: Ed Snider

Overview of this book

Discover how to extend and build upon the components of the Xamarin.Forms toolkit to develop an 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. Discover how to extend and build upon the components of the Xamarin.Forms toolkit to develop an 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, geo-location, and the camera, as well as how to use these services 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—both the app logic through unit tests and the user interface using Xamarin’s UITest framework. Finally, we’ll integrate Xamarin Insights for monitoring usage and bugs to gain a proactive edge on app quality.
Table of Contents (17 chapters)

Offline data caching


Mobile apps have several benefits over web apps, one of which is the ability to operate offline and maintain offline data. There are a couple of reasons why offline data is important to a mobile app. First of all, you cannot guarantee your app will always have a network connection and the ability to directly connect to live data; so, supporting "offline" allows users to use the app, even if only for limited use cases, when they are operating with limited or no connectivity. Second, users expect mobile apps to offer high performance, specifically quick access to data without having to wait. By maintaining an offline cache, an app can present a user with data immediately while it's busy retrieving a fresh data set, providing perceived performance to the user. It is important that when the cache updates, the user receives that updated data automatically so that they are always seeing the latest data possible, depending on specific use cases of course.

There are several ways...