We present a functional take on front-end data-binding. MVC, MVP, MVVM, just the V – there are many useful architectures for data binding when data changes in discrete chunks. For data that changes continuously in time (animations, gesture controlled UI, responsive layout, etc), these are not the best tools. By treating continuously changing layout data in a functional way, and updating discrete changes to a model’s data in an MV* way, we can split the data-binding problem into two cleanly separated problems. In so doing we make all our tools better at what they do best.
via Android Architecture — Android & Tech News — Medium.
MVC Design Pattern splits an application into three main aspects: Model, View and Controller. It forces a separation of concerns, it means domain model and controller logic are decoupled from user interface (view). As a result maintenance and testing of the application become simpler and easier.
via Android Databinding: Goodbye Presenter, hello ViewModel! – VG Tech.
The Model-View-Presenter-pattern (MVP) has been the dominating trend lately when it comes the UI-layer architecture of Android applications. Frameworks like Ted Mosby,Nucleus and Mortar have all talked about Presenters to help you achieving a clean architecture of your app. They also (to a varying degree) help you with the infamous issues of device rotation and state persistence on the Android platform. This isn’t directly related to the concept of MVP, but the pattern helps you isolate the boiler plate code.
Data Binding, as announced on Google I/O 2015 and shipped with the Android M preview as a support library, changes everything. According to the Wikipedia article on MVP, the Presenter has the following tasks:
The presenter acts upon the model and the view. It retrieves data from repositories (the model), and formats it for display in the view.
The thing is that Data Binding framework will take over the main responsibilities of the Presenter (“acting upon the model and the view”), while the remainder is left to the enhanced Model – the ViewModel (“retreiving data from repositories and formatting”). The ViewModel is a standard Java class whose sole responsibility is to represent the data behind a single View. It can merge data from multiple sources (Models) and prepare that data for presentation. I did a short writeup on the ViewModel and how it differs from Data Model or Transport Model.
The architecture we end up with is MVVM – Model-View-ViewModel, and is a proven concept originally coined by Microsoft back in 2005 (don’t let that scare you 😉 ). Let me illustrate the change from MVP to MVVM for you, shamelessly copying Hanne Dorfmann’s illustration from the introduction of his Ted Mosby framework
via danhermes/xamarin-book-examples · GitHub.
The xamarin-book-examples GitHub project contains the complete code examples for the book entitled Xamarin Mobile Application Development by Dan Hermes, published by Apress. This book is a four hundred page journey through Xamarin.Forms, Xamarin.iOS, and Xamarin.Android, covering the entire breadth of the Xamarin platform. These 200+ code examples are freely downloadable and include both C# and XAML.
This weighty book gives clear guidance that will help you build quality apps, starting with architectural considerations, and then jumping into practical code strategies. – Bryan Costanich, Vice President, Xamarin
Many thanks to Xamarin MVP Jason Awbrey and Alex Blount (now a developer at Xamarin) for their XAML contributions. Ten thousand thanks to Xamarin MVP Ed Snider for his tech review of much of this code!