能否用MAUI封装.NET类库编译为AAR/XCFramework用于Flutter原生项目？

一、前置准备 #

• 安装.NET 7+ SDK及MAUI工作负载：执行 dotnet workload install maui
• 确认你的三个.NET类库为.NET Standard 2.0+或.NET 7+版本，且无Windows专属API依赖

二、创建MAUI封装类库 #

1. 终端执行创建命令：dotnet new mauilib -n DotNetNativeWrapper
2. 将你的三个.dll添加为项目引用：编辑项目的.csproj文件，加入以下节点（替换为实际类库路径）：

<ItemGroup>
  <ProjectReference Include="..\YourLibrary1\YourLibrary1.csproj" />
  <ProjectReference Include="..\YourLibrary2\YourLibrary2.csproj" />
  <ProjectReference Include="..\YourLibrary3\YourLibrary3.csproj" />
</ItemGroup>

三、编写原生友好的封装层 #

在MAUI类库中创建公开类，将原.dll的功能封装成原生平台可调用的简单接口，避免复杂自定义类型传递（如需复杂数据可转成JSON字符串）：

namespace DotNetNativeWrapper
{
    public class BusinessService
    {
        private readonly OriginalLib1.CoreService _coreService;

        public BusinessService()
        {
            _coreService = new OriginalLib1.CoreService();
        }

        public string ProcessData(string input)
        {
            return _coreService.Process(input);
        }

        public int CalculateTotal(int[] numbers)
        {
            return OriginalLib2.Calculator.Sum(numbers);
        }
    }
}

四、编译生成Android AAR #

• 切换到MAUI类库目录，执行：dotnet build -f net7.0-android
• 编译产物路径：bin/Debug/net7.0-android/DotNetNativeWrapper.aar（Release版本替换Debug为Release）

五、编译生成iOS Framework #

• 需在Mac环境下操作，切换到MAUI类库目录，执行：dotnet build -f net7.0-ios
• 编译产物路径：bin/Debug/net7.0-ios/DotNetNativeWrapper.framework

六、Flutter项目集成 #

Android端 #

1. 将AAR文件复制到Flutter项目的android/app/libs目录
2. 编辑android/app/build.gradle，添加依赖：

dependencies {
    implementation files('libs/DotNetNativeWrapper.aar')
}

3. 通过MethodChannel调用封装方法（示例Kotlin代码）：

import io.flutter.embedding.android.FlutterActivity
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.plugin.common.MethodChannel
import com.dotnetnativewrapper.BusinessService

class MainActivity : FlutterActivity() {
    private val CHANNEL = "com.example/dotnet_service"

    override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
        super.configureFlutterEngine(flutterEngine)
        MethodChannel(flutterEngine.dartExecutor.binaryMessenger, CHANNEL).setMethodCallHandler { call, result ->
            when (call.method) {
                "processData" -> {
                    val input = call.argument<String>("input") ?: ""
                    val service = BusinessService()
                    result.success(service.processData(input))
                }
                else -> result.notImplemented()
            }
        }
    }
}

iOS端 #

1. 将Framework复制到Flutter项目的ios/Frameworks目录（无此目录则新建）
2. 打开ios/Runner.xcworkspace，将Framework拖入项目，勾选"Copy items if needed"，并在Target的「Frameworks, Libraries, and Embedded Content」中设置为「Embed & Sign」
3. 通过MethodChannel调用封装方法（示例Swift代码）：

import UIKit
import Flutter
import DotNetNativeWrapper

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
    private let CHANNEL = "com.example/dotnet_service"

    override func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        let controller = window?.rootViewController as! FlutterViewController
        let channel = FlutterMethodChannel(name: CHANNEL, binaryMessenger: controller.binaryMessenger)
        channel.setMethodCallHandler { call, result in
            switch call.method {
            case "processData":
                let input = call.arguments?["input"] as? String ?? ""
                let service = BusinessService()
                result.success(service.processData(input))
            default:
                result.notImplemented()
            }
        }
        GeneratedPluginRegistrant.register(with: self)
        return super.application(application, didFinishLaunchingWithOptions: launchOptions)
    }
}

Flutter Dart端调用 #

import 'package:flutter/services.dart';

class DotNetService {
  static const MethodChannel _channel = MethodChannel('com.example/dotnet_service');

  static Future<String?> processData(String input) async {
    final String? result = await _channel.invokeMethod('processData', {'input': input});
    return result;
  }
}

内容的提问来源于stack exchange，提问作者ASP