Xamarin Cross-platform Application Development

If you're getting started in cross-platform (particularly iOS and Android) Xamarin programming, Jonathan Peppers' "Xamarin Cross-platform Application Development" might be the book for you.Structure-wise, the first two chapters provide the basics of the tools and, of course, the obligatory "Hello …" sample app: In this case, "Hello Platform".The next 5 chapters focus largely on the development and deployment of a cross-platform "XamChat" application. There are individual chapters focusing on the iOS and Android aspects as well as a chapter on creating the cross-platform aspects.The last few chapters cover various topics common to Xamarin/mobile development (3rd party components, binding to native libraries, GPS, Camera, Contacts and app stores).One of the key benefits of Xamarin development is the opportunity for code-sharing between mobile apps (iOS, Android and Windows Phone). As Xamarin is primarily focused at Android and iOS, both Xamarin's web site and this book, provide only passing mention of WP8 development. That said, many of the techniques discussed in the book on cross-platform development, would carry over to a Windows phone app.This book has a number of strong points; It covers many of the major areas that mobile developers and Xamarin developers will run into. It covers the basics of the software needed for each platform. It covers the tools and how to use them. It discusses some of the platform-specific controls and techniques. It discusses how to use the basic facilities that most apps use (camera, GPS, etc). And it covers a lot of the details of getting your app into the iOS App Store and Google Play.What this book won't provide is a lot of detail about Android development and iOS development; which is to say, if you're doing a moderately complex app, you're bound to get into areas not covered by this book. Android and iOS are both very rich platforms and to cover either in great detail would require separate books, so it would be unreasonable to expect this book to cover both platforms in great detail. So if you're unfamiliar with these platforms, you'll need additional resources.The book seems to assume the reader is going to go with the MVVM (Model-View-ViewModel) design pattern. In fact, MVVM Cross is probably the most popular development framework for Xamarin and so, this is probably not a bad assumption. But readers should be aware that other patterns can be used as well.Xamarin provides Xamarin Studio (a cross-platform IDE for Xamarin apps) as well as Visual Studio integration. This book only looks at Xamarin Studio, so if you're using the Visual Studio integration, some aspects of project management will be different.Bottom line: If you're getting started with Xamarin programming, this book is a really good introduction. It covers the basics of Xamarin and general mobile development; certainly enough to get anyone up and running and writing basic applications. This book would be of limited value to someone who's already done some Xamarin development and it would be of limited value as a long-term reference.

While this book covers some good concepts regarding cross-platform development, I simply can't excuse the amount of technical code errors there are. Throughout my read, I found that variables suddenly existed in some samples, as well as syntax errors and other unexplained items that forced me to figure out where I had gone wrong (when I had done everything to the letter).I recommend this book for its concepts in Xamarin cross-platform development, but don't bother coding alongside the Android sample application in the book - you will not be able to complete it just with the samples alone.

This book is openly marketed at existing, experienced C# developers so it's certainly not for beginners, and whilst I don't fall into this category the nature of projects I work in require mostly 'linear' development (Web, PHP, Perl, Python, VB etc over the years) so concepts like MVC, MVVM and in particular IOC (Inversion of Control) are newer and less clear. Thankfully this book has resolved that through it's excellent practical examples.One area this book doesn't touch on hugely is the level of planning required for MVC applications, you can't just 'jump in and code', but that's potentially a book in itself, but what the book does very well for me, is explain the View, ViewModel, Model and Controller concepts in terms of the classes and data layers required. The book also introduces Interfaces (something I always saw as an unnecessary layer of complexity) which I now 'get' in terms of flexibility, and in particular to give the developer options in a cross platform environment.The icing on the cake is 'Inversion of Control', whilst the book doesn't particularly explain this convention in huge detail, I think it is actually to it's credit, any more and the reader will be bogged down in unnecessary detail and complexity. It basically gives us the service layer that 'glues' the application together, allowing use to create and register our ViewModels as Services and thus make them available to use throughout the app with a single line of code. I'm sure that my description is not hugely more constructive than the words in the book themselves, but the working example of the XamChat application completes it.Which is my main point, am sure many people work differently, but for me working examples of code are what makes it stick in my mind, it helps it all make sense. Throughout this book you will be building bit buy bit a working chat application, firstly in Xamarin.iOS (but using the all important cross platform and code sharing concepts learnt at the beginning of the book), and then re-implementing the same application logic in Xamarin.Android. The nice touch, which some may see as lazy, was that with the Android example you are taken to a certain point and then left to finish off using the examples you already have. A real, and practical exercise which I think will do the reader good. It wouldn't be a huge leap further to recreate in Windows Phone, for the ultimate practical extension.The Xamchat application is then extended through the Windows Azure platform to use their backend for data storage (a good example of how the same Interface can be re-used to store on different platforms), and to implement cross platform push notifications.Lastly there are chapters on using Xamarin Components (including Xamarin.Mobile for Contacts, Camera and Location functionality), and actual App Store submission and their different processes, processes that even the most experienced developer can struggle with (Apple Certificates and Profile expiry anyone!).In summary, this is an excellent book for any would be cross platform mobile application developer, yes you need a good understanding of C#, MVC and similar concepts, and the individual mobile platforms and general development processes themselves, and those things don't come over night, but this book binds it all together with real world examples, working code (a novelty for some books) and actual code and methods you can take away and use in the real world.Buy it, read it, and take as much as you can from it.

Between the screenshots and the code listing, I hoped to see at least a whole chapter on mvvm, dependency injection and inversion of control which are quite central in xamarin, but they are juste mentioned.