MVVM frameworks - MvvmCrossFlavius-Radu DEMIAN

A bit about me

• General Manager@Deventure

• Timisoara .Net Meetup organizer

• Mobile and Web developer

• Xamarin and Umbraco enthusiast

• In love with technology

flavius.demian@deventure.co @flaviusdemian

Agenda

Xamarin’s Unique ApproachWhat is MVVM?Why MVVM?The MvvmCross magic Data-Binding, Commands, NavigationAdvantagesDisadvantages

Expectations

I wish to have an interactive presentation.Please feel free to ask questions any time.

My ultimate goal is to make you

curios.

Go home and try it yourself!

Xamarin’s Unique Approach

Xamarin’s Unique Approach

Xamarin’s Unique Approach

• native user interface• native performance• shared code across platforms• usage of C# & .NET framework• full API coverage• fewer developers

The Xamarin MagicWrite Everything in C#

The Xamarin MagicXamarin takes the C# code and it compiles it down to native on iOS and Android.

The magic is that you can also use it on the Windows platform.

(Almost) everything you can do in Objective-C, Swift or Java can be also done in C# with Xamarin.Check the limitations on www.xamarin.com .

Since you use C# on all the platforms, code reuse varies from 60% to 90%.

Xamarin Architecture Guide

What is MVVM?

Model View ViewModel

MVVM Technical DetailsIt is derived from the Model View Controller Pattern.

• properties• data binding• INotifyPropertyChanged• INotifyCollectionChanged• IValueConverter• ICommand• UI thread

Why MVVM?

MVVM Pros and ConsThere is a reason why it’s called a pattern.Pros:• separation of concerns• decoupling• code reuse• testability

Cons:• MVVM is "overkill" for simple UI operations

The MvvmCross Magic

The MvvmCross Magic

It’s an open-source framework maintained by Stuart Lodge, Martijn van Dijk & Co.

It has Dependency Injection built-in -> Interface Driven Design.

It has a lot of plugins already written such as location, emails, gallery, network, SQLite, secure storage, phone calls etc.

#IF plugins -> less work for the developer, but also less control.

The MvvmCross Magic

The MvvmCross Magic

MvvmCross has support for:• Xamarin.iOS• Mac• Xamarin.Android• Windows Presentation Foundation• Windows Phone• Windows 8• Universal Windows Platform

The MvvmCross MagicIt has huge popularity and the community is very active.

https://jabbr.net/#/rooms/mvvmcrosshttps://xamarinchat.slack.com/messages/mvvmcross/https://github.com/MvvmCross/MvvmCross

Data Binding, Commands, Navigation

Data Binding - Properties

No C#, just XAML

<TextBox Text="{Binding Password, Mode=TwoWay}" />

Data Binding - Properties

No C#, just XML

xmlns:local="http://schemas.android.com/apk/res-auto"<EditText local:MvxBind="Text Password"

Data Binding - Properties

Just C#

var set = this.CreateBindingSet<LoginViewController, LoginViewModel>(); set.Bind(textField_Password).To(vm => vm.Password);

Data Binding - ListviewsNo C#, just XAML

<ListBox ItemsSource="{Binding MyCollection}"<ListBox.ItemTemplate>

<DataTemplate> …..</DataTemplate>

</ListBox.ItemTemplate></ListBox>

Data Binding - Listviews

No C#, just XML

<Mvx.MvxListView local:MvxBind="ItemsSource MyCollection; ItemClick ViewDetailsCommand"local:MvxItemTemplate="@layout/item_template_row" />

Data Binding - Listviews

Just C#

var set = this.CreateBindingSet<XViewController, XViewModel>();set.Bind(source).To(x => x.MyCollection);set.Apply();

ViewModel Commands

No C#, just XAML

xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"xmlns:commandbinding="clr-namespace:Cirrious.MvvmCross.WindowsPhone.Commands;assembly=Cirrious.MvvmCross.WindowsPhone" <TextBlock Text="{Binding Name}">

<i:Interaction.Triggers><i:EventTrigger EventName="Tap">

<commandbinding:MvxEventToCommand Command="{Binding MyCommand}" />

</i:EventTrigger></i:Interaction.Triggers>

</TextBlock>

ViewModel Commands

No C#, just XML

xmlns:local="http://schemas.android.com/apk/res-auto"<Button local:MvxBind="Click LoginCommand" />

ViewModel Commands

Just C#

var set = this.CreateBindingSet<LoginViewController, LoginViewModel>();set.Bind(btn_Login).To(x => x.LoginCommand);set.Apply();

Navigation

Go forward:CurrentViewModelInstance.ShowViewModel<NewViewModel>();

Navigation

Go back:CurrentViewModelInstance.Close(this);

MvvmCross App Architecture

App ArchitectureThe project should be split in 2:

Common core which contains:• models• viewmodels• business logic• data access layer

UI-project per platform:• each platform views

Small Demo Time

MvvmCross Pros & Cons

Pros:• interchangeable code module• supports Test Driven Development (TDD)• it follows the Core pattern• it has data binding

MvvmCross Pros & Cons

Cons:• it is a non-native pattern for iOS -MVC- and Android -

aprox MVC-• core 3rd party dependency• lot’s of glue code for custom bindings

Thank you very much.