Multi platform mobile device development in C#

This recherche decribes possibilities of the multi platform mobile device development in C#. It investigates the advantages, disadvantages and challenges associated with multiplatform development, considering factors such as code sharing, performance, user experience and support.

Frameworks & tools to write cross-platform applications in C#

Xamarin

• Open source cross-platform development framework allowing to build native mobile applications for iOS and Android using the C#
• Abstraction layer manages communication of shared code with underlying platform code
• Shared code is bound into underlying platform SDKs - by iOS (Xamarin.iOS) and Android (Xamarin.Android)
• Xamarin application can use .NET BCL which is known by C# developers
• Existing C# code can be recompiled and used in Xamarin application
• Apps are compiled in native code - .apk file on Android, or an .ipa file on iOS
• Native platform Interop - possiblity of invoking native platform libraries
• Provides Xamarin.Essentials API to access resources across all platforms

Pros:

• Code reusability
• Performance - compilation into native code
• Single language knowledge needed - C# - for application code
• Open source
• Community suppport

Cons:

• UI has to be written using native libraries
• Delay in support of platform specific features
• Xamarin app is larger than native app (Mono runtime and BCL assemblies)

Xamarin.Forms

• Open source UI framework - part of Xamarin platform - for building user interfaces across multiple platforms
• User interfaces are created in XAML or C#, MVVM supported
• UI is rendered as native platform controls by target platform renderers
• Application typically consist of shared .NET (bussiness logic, UI) and platform specifics projects
• Xamarin.Forms platform-specifics allows utilization of specific feature available only on specific platform
• Development can be even simplified by usage Xamaring.Forms Shell providing common navigation, search, app structure and layout basis

Pros:

• Single code base application development - C# and XAML
• Saves development time and effort
• Native app performance and look - due compilation in native code
• Prebuild controls and layouts
• Access to target platform specific features
• Support to build custom reusable UI components

Cons:

• Customization limitations - provided pre-build controls may not cover app requrements
• Performance overhead compared to native apps - shared controls mapping can add additional processing and redering steps
• Not all platform specifics are available
• Larger Xamarin.Forms app size than native app
• Platform specific availability delay
• Shared Xamarin.Forms UI controls may restrict certain design choices or require additional customization

.NET MAUI

• Multi-platform App UI is the evolution of Xamarin.Forms, a open source, cross-platform UI framework for building native apps
• Can build native mobile, desktop and web applications using a shared codebase and UI
• Can run on multiple platforms including iOS, Android, macOS and Windows
• Uses a series of platform-specific frameworks for creating apps: .NET Android, .NET iOS, .NET macOS, and Windows UI 3 (WinUI 3) library provided by .NET6 or greater
• These frameworks have access to the same .NET BCL and this libraries abstracts the details of the underlying platform
• MAUI provides also a single framework for building the UIs, but platform specifics UI's can be also defined separately using .NET Android, .NET iOS, .NET macOS or WinUI 3
• As evolution of Xamarin.Forms are also provided cross platform API's for accessing device features, collection of prebuild controls, layouts and databinding support
• Is compatibile with existing Xamarin.Forms projects, allowing developers to migrate their existing apps

Pros (over Xamarin.Forms):

• Single project structure with multitargeting - combining the shared code and resources for multiple platforms into a single project file
• Performance enhancements - new rendering architecture, optimized layouts and improved startup time
• Extended target platforms support - macOS, Linux planned but not released yet
• Improved controls, layouts and styling options
• Hot Reload introduced - code and UI changes while the app is running. Also available in latter Xamarin.Forms

Cons (over Xamarin.Forms):

• Early development stage - there may have be different level of stability and ecosystem support as its predecessor Xamarin.Forms
• Compatibility with existing Xamarin.Forms code - there may still be challenges in migrating existing codebases
• Limitted third party libraries support
• Limitted tooling and community support

Tooling

• Visual Studio/Visual Studio for Mac - most commonly used IDE for C# mobile app development, supports Xamarin and .NET MAUI development
• Visual Studio Code - lightweight and extensible code editor supporting Xamarin and .NET MAUI projects
• Xamarin.Forms Previewer - tool integrated into Visual Studio that allows developers to preview the user interface
• App Center - mobile app development and management platform by Microsoft. Provides build automation, testing, distribution, crash reporting, and analytics.

Roadmap of hard skills to develop mobile device apps in C# using .NET MAUI

• Basics

  • Learn concepts of .NET MAUI, changes in comparison to Xamarin.Forms
  • Understand the single-project structure and how it differs from Xamarin.Forms
  • Learn about the new features and improvements introduced in .NET MAUI compared to Xamarin.Forms

• UI development

  • Explore controls and view layouts available
  • Understand navigation and routing
  • Get familar with resources usage

• Data access

  • Learn about storage options
  • Get familar with SQLite database usage

• Work with REST API

  • Consume REST API
  • Perform CRUD operations

• Advaced topics

  • Understand how to develop platform specific features
  • Learn authentication and security concepts

• Deployment

  • App packaging, code signing, deployment to target platform store
  • Specifics of target platform app stores

List skills/knowledge outside .NET platform to develop feature-rich mobile apps

Native Development with Platform-specific Tools

Native development offers the most direct access to platform-specific features and performance but requires specific knowledge for each platform. Generally saying each platform has it's own specific of: application infrastructure, data persistence, networking, background processing, testing and debugging, CI/CD.

iOS

• Swift or Objective-C knowledge - as they are the primary languages used for iOS app development
• iOS Software Development Kit (SDK) knowledge
• Xcode is official IDE for iOS app development
• Understanding the principles of UI design for iOS apps
• App Store app deployment
• Testing tools: XCTest
• CI/CD: Bitrise or Jenkins

Android

• Java or Kotlin knowledge - as they are the primary languages used for Android app development
• Android Software Development Kit (SDK) knowledge
• Android Studio official IDE
• Understanding the principles of UI design for Android apps, Android UI layouts using XML files.
• Google Play Store app deployment
• Testing tools: JUnit, Espresso or Mockito
• CI/CD: Jenkins

There is also several possibilities to use C# with other frameworks.

Flutter with C#

Flutter is a popular open-source framework developed by Google that allows you to build cross-platform mobile apps using the Dart programming language. Flutter primarily uses Dart, there are community-driven projects like Flutter for Xamarin that enable you to write Flutter code in C#. https://docs.flutter.dev/get-started/flutter-for/xamarin-forms-devs https://www.flutnet.com/

Unity with C#

Unity is primarily used for game development, it can also be used to create interactive mobile applications. https://unity.com/how-to/learning-c-sharp-unity-beginners#what-languages-can-you-use-unity--2

React Native with C#

React Native is a framework developed by Facebook for building cross-platform mobile applications using JavaScript. React Native can be used with C# through projects like React Native for Xamarin https://microsoft.github.io/react-native-windows/docs/native-code-language-choice

Conclusion

Before decision to use multi platform mobile device app development is always needed to evaluate following considerations:

• Evaluate the complexity (especially UI complexity) of your app, mostly platform specifics will have to implemented separately
• If high performance or utilize platform-specific optimizations is needed then native development may be a better choice
• Collect platforms you need to target and evaluate their support
• Evaluate development timeline and budget for your project. Here single code base can be benefitial.