Book Image

Xamarin 4.x Cross-Platform Application Development - Third Edition

By : Jonathan Peppers
Book Image

Xamarin 4.x Cross-Platform Application Development - Third Edition

By: Jonathan Peppers

Overview of this book

Xamarin is a leading cross-platform application development tool used by top companies such as Coca-Cola, Honeywell, and Alaska Airlines to build apps. Version 4 features significant updates to the platform including the release of Xamarin.Forms 2.0 and improvements have been made to the iOS and Android designers. Xamarin was acquired by Microsoft so it is now a part of the Visual Studio family. This book will show you how to build applications for iOS, Android, and Windows. You will be walked through the process of creating an application that comes complete with a back-end web service and native features such as GPS location, camera, push notifications, and other core features. Additionally, you’ll learn how to use external libraries with Xamarin and Xamarin.Forms to create user interfaces. This book also provides instructions for Visual Studio and Windows. This edition has been updated with new screenshots and detailed steps to provide you with a holistic overview of the new features in Xamarin 4.
Table of Contents (19 chapters)
Xamarin 4.x Cross-Platform Application Development - Third Edition
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Accessing contacts


To begin our exploration of what Xamarin.Mobile offers, let's access the address book within a Xamarin application. Let's improve the add friend feature of XamSnap by loading friends from the user's contact list. Make sure to add Xamarin.Mobile to the project from the Component Store for both the iOS and Android projects.

Navigate to the XamSnap portable class library. First, we will need to split apart the IWebService interface, by moving one method to a new IFriendService interface:

public interface IFriendService 
{ 
    Task<User[]> GetFriends(string userName); 
} 

Next, in FriendViewModel, we will need to use the new IFriendService interface instead of the old one:

private IFriendService friendService =  
  ServiceContainer.Resolve<IFriendService>(); 
 
public async Task GetFriends() 
{ 
  //previous code here, use 'friendService' instead of 'service' 
  Friends = await friendService.GetFriends(settings.User...