Xamarin

What I do

• Build cross-platform mobile apps with C# and .NET
• Develop native iOS and Android apps with Xamarin
• Create Xamarin.Forms for shared UI code
• Implement platform-specific features with Effects and Renderers
• Use .NET libraries and NuGet packages
• Share code across iOS, Android, and Windows
• Integrate with Azure services

When to use me

Use me when:

• Teams with C#/.NET expertise
• Existing .NET codebase to extend to mobile
• Enterprise apps requiring Azure integration
• Need shared business logic across platforms
• Windows mobile target needed
• Requiring deep native API access

Key Concepts

Xamarin Architecture

Xamarin compiles C# to native code, providing full API access:

┌─────────────────────────────────────────────┐
│            Shared C# Code                   │
│  (Business Logic, Models, ViewModels)       │
└──────────────────┬──────────────────────────┘
                   │
        ┌──────────┴──────────┐
        ▼                     ▼
┌───────────────┐      ┌───────────────┐
│   Xamarin    │      │    Xamarin    │
│     iOS      │      │   Android    │
│  (AOT/Mono)  │      │   (Mono VM)  │
└───────────────┘      └───────────────┘

Xamarin.Forms

Declarative UI shared across platforms:

public class App : Application
{
    public App()
    {
        MainPage = new NavigationPage(new MainPage());
    }
}

public class MainPage : ContentPage
{
    public MainPage()
    {
        var button = new Button { Text = "Click Me" };
        var label = new Label { Text = "Counter: 0" };
        int count = 0;

        button.Clicked += (s, e) =>
        {
            count++;
            label.Text = $"Counter: {count}";
        };

        Content = new StackLayout
        {
            Children = { label, button },
            VerticalOptions = LayoutOptions.Center
        };
    }
}

Platform-Specific Customization

• Effects: Lightweight customizations
• Custom Renderers: Full native control
• DependencyService: Platform-specific implementations

.NET Integration

• Azure Functions
• Entity Framework Core
• ASP.NET Core backend sharing
• NuGet packages