Xamarin Interview Questions and Answers

This section covers frequently asked Xamarin interview questions.

1. What is Xamarin?

Xamarin is a Microsoft-owned framework for building cross-platform mobile apps using C#, allowing developers to share code between iOS, Android, and Windows platforms while creating native-like user interfaces (UIs).

2. Advantages of Xamarin Development.

  • Native-like UI
  • Cross-platform development
  • Reduced code duplication
  • Strong community support

3. Disadvantages of Xamarin Development.

  • UI development can be time-consuming.
  • Larger app sizes compared to native apps.
  • Platform-specific code may still be required.

4. Xamarin Development Approaches.

  • Xamarin.Forms: Creates a single UI shared across platforms.
  • Xamarin.Native: Creates separate UIs for each platform.

5. Xamarin vs. Xamarin.Forms.

Feature Xamarin Xamarin.Forms
UI Development Platform-specific Cross-platform (shared UI)
Code Sharing Partial High

6. Xamarin Profiler.

The Xamarin Profiler helps analyze app performance (memory usage, etc.) within Visual Studio.

7. Xamarin Insights.

Xamarin Insights (discontinued) provided real-time crash reporting and performance monitoring. Visual Studio App Center now offers similar features.

8. Xamarin.Forms.

Xamarin.Forms provides a framework for building cross-platform UIs with shared code.

9. Programming Languages Supported by Xamarin.

  • C#
  • F#
  • Visual Basic .NET

10. Role of XAML in Xamarin.

XAML (Extensible Application Markup Language) is used for defining UIs in Xamarin.Forms and Xamarin.Native projects. While not strictly required for Xamarin.Forms, it’s commonly used for its declarative nature.

11. Xamarin Studio.

Xamarin Studio (based on MonoDevelop) was a standalone IDE for Xamarin development. It's now largely replaced by Visual Studio.

12. Xamarin Studio vs. Visual Studio.

IDE Platform Support
Xamarin Studio Windows and macOS
Visual Studio Windows

13. Lifecycle of Xamarin.Forms Apps.

(This section would describe the lifecycle of a Xamarin.Forms application, mentioning the roles of the portable project, platform-specific projects, and the UI development process.)

14. Data Binding Modes.

  • Default
  • OneWay
  • TwoWay

15. Xamarin vs. Mono.

Framework Target Cost
Xamarin Cross-platform Lower (relatively)
Mono Single platform Higher (relatively)

16. Scenarios in Xamarin.Forms.

(This section would list various data binding scenarios within Xamarin.Forms.)

17. Data Binding in Xamarin.

Data binding synchronizes UI elements with data. Changes in the data source automatically update the UI, and vice-versa (in two-way binding).

18. Xamarin Test Cloud.

Xamarin Test Cloud (now part of Visual Studio App Center) allows for automated testing on various devices.

19. Setting Up Xamarin.

(This section would outline the steps for installing and configuring Xamarin within Visual Studio.)

20. Layout Controls in Xamarin.Forms.

(This section would list various layout controls available in Xamarin.Forms, such as StackLayout, Grid, RelativeLayout, AbsoluteLayout, etc.)

21. Page Types in Xamarin.Forms.

(This section would list different page types available in Xamarin.Forms: ContentPage, MasterDetailPage, NavigationPage, TabbedPage, CarouselPage.)

22. Advantages of Xamarin.

  • Cross-platform development using C# and XAML.
  • Access to native APIs.
  • Component store.
  • Code-sharing techniques (PCLs, shared projects).

23. Code-Sharing Techniques.

  • Portable Class Libraries (PCLs): Create libraries that are compatible with multiple platforms.
  • Shared Projects: Share code between projects.

24. Portable Class Libraries (PCLs) vs. Shared Projects.

Approach Description Advantages Disadvantages
PCLs (Portable Class Libraries) Create a separate library targeting multiple platforms. Improved code organization, reusability across different platforms Can be restrictive in terms of the APIs available.
Shared Projects Share code directly between projects. Greater flexibility to use platform-specific APIs. Less organized compared to PCLs. Requires more attention during development.

25. Advantages of XAML.

  • Clear separation of UI design from code.
  • Concise syntax.
  • Declarative UI definition.
  • Simplified UI design and development workflow.

26. Views in Xamarin.Forms.

Views are UI elements (controls) in Xamarin.Forms, such as labels, buttons, and list views.

27. ListView vs. TableView.

Control Layout
ListView Vertical
TableView Horizontal (rows)

28. Applications Built with Xamarin.

(This section would list example applications built using Xamarin.)

29. Data Binding Scenarios.

(This section lists various data binding scenarios in Xamarin.Forms.)

30. Apps Designed by Xamarin for Android.

(This section would list example apps developed by Xamarin for Android.)

31. Apps Designed by Xamarin for iOS.

(This section would list example apps developed by Xamarin for iOS.)

32. How Xamarin.Android Applications Work.

Xamarin.Android apps utilize Mono, an open-source .NET implementation, working alongside Android's ART (Android Runtime). This allows you to use C# to create Android apps.

33. Fresh MVVM.

Fresh MVVM is a lightweight MVVM framework for Xamarin.Forms, simplifying development.

34. MVVM Cross vs. MVVM Light.

Framework Platform Support Features
MVVM Cross Cross-platform (.NET) Navigation, data binding, IoC container
MVVM Light Cross-platform (.NET) Simple MVVM implementation

35. Need for MVVM in Xamarin.

MVVM (Model-View-ViewModel) separates UI from business logic, improving testability, maintainability, and collaboration between designers and developers.

36. NuGet Package Manager.

NuGet is a package manager for .NET, allowing you to easily add third-party libraries to your Xamarin projects.

37. HTTPClient in Xamarin.

HttpClient is used for making HTTP requests to external services (like REST APIs).

38. ResourceDictionary.

ResourceDictionary helps manage and reuse XAML resources (styles, templates, etc.) across a Xamarin.Forms application.

39. Xamarin.Forms vs. Xamarin.Native (Repeated from earlier section).

Approach UI Code Sharing
Xamarin.Forms Shared across platforms High
Xamarin.Native Platform-specific Less

40. App.cs Class.

App.cs is the entry point of a Xamarin.Forms application, setting up the initial page and managing application resources.

41. Xamarin.Forms App Lifecycle Methods.

  • OnStart()
  • OnSleep()
  • OnResume()

42. XAML Compiler (XamlC).

XamlC compiles XAML to intermediate language (IL), improving performance and enabling compile-time error checking.

43. XAML Namespace Declarations.

Namespace declarations (like xmlns) define the namespaces used in a XAML file, providing access to various elements and properties.

44. Navigation in Xamarin.Forms.

C# Code

await Navigation.PushAsync(new MySecondPage());

45. ViewCell.

ViewCell is a template for individual items in a ListView or TableView.

46. Built-in Cell Types.

(This section lists the built-in cell types: TextCell, ImageCell, SwitchCell, EntryCell.)

47. ControlTemplate vs. DataTemplate.

ControlTemplate styles a control's appearance; DataTemplate defines how data is displayed within a control.

48. Triggers in XAML.

Triggers define actions that occur when a specific condition is met. Types include PropertyTrigger, DataTrigger, EventTrigger, and MultiTrigger.

49. HockeyApp and TestFlight.

HockeyApp (now part of Microsoft Visual Studio App Center) and TestFlight (Apple) are used for beta testing mobile applications.

50. Ways to Create Xamarin Applications.

  • Xamarin.Forms
  • Xamarin.Android
  • Xamarin.iOS