NativeBinding

Automated native SDK binding generator for .NET MAUI. This project uses AI agents (Claude Code and GitHub Copilot) to fully automate the creation of .NET MAUI native bindings from iOS and Android SDKs — including artifact discovery, API research, code generation, build verification, and testing.

How It Works

The workflow is available as:

• Claude Code command: .claude/commands/create-binding.md
• Copilot prompt file: .github/prompts/create-binding.prompt.md

When invoked, it runs through 8 phases autonomously:

Phase 1: Setup

Creates the output directory structure with ios/, android/, unified/, and tests/ subdirectories.

Phase 2: Fetch Artifacts

• Android: Searches Maven Central API, downloads the AAR (and companion core JARs for Kotlin SDKs), verifies the archive.
• iOS: Searches GitHub releases for a pre-built XCFramework. If none exists, clones the source repo and builds from source using swift build with explicit iOS triples, packages .o files into static libraries with ar, and creates an XCFramework via xcodebuild -create-xcframework.

Phase 3: Research API

Reads ObjC headers from the XCFramework and inspects Android AAR class files with javap. Cross-references with official SDK documentation to build a complete API model.

Phase 4: Generate Bindings

• iOS: Generates ApiDefinition.cs with [BaseType], [Export], [Protocol], [Static], [NullAllowed] attributes mapped from ObjC headers. Generates StructsAndEnums.cs for enums. Creates the .csproj with IsBindingProject, ObjcBindingApiDefinition, ObjcBindingCoreSource, and NativeReference.
• Android: Generates Transforms/Metadata.xml for Java-to-C# namespace mapping and removal of internal/problematic types. Creates the .csproj with TransformFile and AndroidLibrary references.

Phase 5: Unified MAUI API

Creates a cross-platform C# interface (IAmplitudeService) with platform-specific implementations under Platforms/iOS/ and Platforms/Android/. Includes a MauiAppBuilder extension method for DI registration.

Phase 6: Generate Tests

Creates xUnit tests that validate the generated source files as text — checking file existence, namespace declarations, required attributes, API surface presence, and project structure. Tests target net10.0 (not platform-specific TFMs) so they run on any machine.

Phase 7: Build & Verify

Builds all projects in dependency order, runs tests, and iteratively fixes any errors (up to 5 attempts). Common fixes are applied automatically: namespace clashes, Metadata.xml adjustments, missing dependencies, type conversion issues.

Phase 8: Report

Prints a summary with status, files created, build results, test results, and next steps for integration.

Usage

Claude Code:

/create-binding <sdk-name> <platform: ios|android|both> [type: service|view] [output-dir]

Copilot Chat (prompt file):

/create-binding

Then provide inputs for sdk-name, platform, optional type, and optional output-dir.

Examples:

/create-binding Amplitude both ./output/amplitude
/create-binding Firebase ios ./output/firebase
/create-binding Lottie android ./output/lottie
/create-binding GoogleMaps both view ./output/googlemaps

Example Output: Amplitude SDK

The output/amplitude/ directory contains a complete binding for the Amplitude analytics SDK targeting both iOS and Android.

Generated Files

output/amplitude/
├── android/
│   ├── Additions/Additions.cs              # Manual binding additions
│   ├── Amplitude.Binding.Android.csproj    # Android binding project
│   ├── Transforms/
│   │   ├── EnumFields.xml                  # Java constant → C# enum mappings
│   │   └── Metadata.xml                    # Java package → C# namespace mappings
│   ├── analytics-android-1.21.3.aar        # Amplitude Android SDK artifact
│   └── analytics-core-1.21.3.jar           # Core types (Configuration, Events, etc.)
├── ios/
│   ├── Amplitude.Binding.iOS.csproj        # iOS binding project
│   ├── Amplitude.xcframework/              # Built from source (v8.22.2)
│   │   ├── ios-arm64/                      # Device slice (static library + headers)
│   │   └── ios-arm64-simulator/            # Simulator slice (static library + headers)
│   ├── ApiDefinition.cs                    # ObjC → C# binding definitions
│   └── StructsAndEnums.cs                  # Enums (AMPServerZone)
├── unified/
│   ├── Amplitude.Maui.csproj              # Cross-platform MAUI project
│   ├── IAmplitudeService.cs               # Platform-agnostic C# interface
│   ├── AmplitudeServiceExtensions.cs      # DI registration (.UseAmplitude())
│   └── Platforms/
│       ├── Android/AmplitudeService.cs    # Android implementation
│       └── iOS/AmplitudeService.cs        # iOS implementation
└── tests/
    ├── Amplitude.Binding.Tests.csproj     # xUnit test project
    ├── CompilationTests.cs                # Source file validity checks
    ├── ApiPresenceTests.cs                # API surface verification
    └── SmokeTests.cs                      # Structure & attribute checks

Build & Test Results

Status: SUCCESS

Build Results:
  ✓ Amplitude.Binding.iOS.csproj      — Built successfully
  ✓ Amplitude.Binding.Android.csproj  — Built successfully
  ✓ Amplitude.Maui.csproj             — Built successfully (both TFMs)
  ✓ Amplitude.Binding.Tests.csproj    — Built successfully

Test Results: 61 passed, 0 failed, 0 skipped

  CompilationTests:
    ✓ iOSApiDefinition_Parses_As_Valid_CSharp
    ✓ iOSStructsAndEnums_Parses_As_Valid_CSharp
    ✓ AndroidMetadata_Is_Valid_Xml
    ✓ UnifiedInterface_Parses_As_Valid_CSharp
    ✓ UnifiediOSImpl_Parses_As_Valid_CSharp
    ✓ UnifiedAndroidImpl_Parses_As_Valid_CSharp
    ... (18 tests)

  ApiPresenceTests:
    ✓ iOS_Has_Amplitude_Class
    ✓ iOS_Has_AMPIdentify_Class
    ✓ iOS_Has_AMPRevenue_Class
    ✓ iOS_Has_LogEvent_Method
    ✓ Android_Has_Amplitude_Namespace
    ✓ Android_Has_Revenue_Mapping
    ✓ Unified_Interface_Has_Initialize
    ✓ Unified_Interface_Has_LogEvent
    ✓ Unified_Interface_Has_LogRevenue
    ... (32 tests)

  SmokeTests:
    ✓ iOSApiDefinition_Has_Correct_Namespace
    ✓ iOSApiDefinition_Uses_Required_Attributes
    ✓ iOSApiDefinition_Uses_Required_Usings
    ✓ iOSCsproj_IsBindingProject
    ✓ AndroidCsproj_HasCorrectStructure
    ✓ AndroidMetadata_HasPackageMappings
    ✓ UnifiedCsproj_HasCorrectStructure
    ✓ UnifiedDIExtensions_Exists_And_Registers_Service
    ✓ XcFramework_Exists_InOutputDirectory
    ✓ AndroidAar_Exists_InOutputDirectory
    ... (11 tests)

How to Use in a MAUI App

1. Add a project reference to the unified project:

   <ProjectReference Include="path/to/output/amplitude/unified/Amplitude.Maui.csproj" />

2. Register the service in MauiProgram.cs:

   var builder = MauiApp.CreateBuilder();
   builder.UseAmplitude();

3. Inject and use IAmplitudeService:

   public class MyViewModel
   {
       private readonly IAmplitudeService _amplitude;
   
       public MyViewModel(IAmplitudeService amplitude)
       {
           _amplitude = amplitude;
           _amplitude.Initialize("YOUR_API_KEY");
       }
   
       public void TrackButtonPress()
       {
           _amplitude.LogEvent("button_pressed", new Dictionary<string, object>
           {
               ["button_name"] = "signup"
           });
       }
   }

Prerequisites

• .NET 10 SDK
• Xcode or Xcode-beta (for iOS bindings)
• MAUI workloads: dotnet workload install maui-ios maui-android
• gh CLI (for fetching iOS artifacts from GitHub releases)