Flutter加密算法插件iso9797的使用

在Flutter中使用加密算法插件 iso9797 可以帮助开发者实现特定的加密需求。虽然Flutter的官方库中并没有直接提供 iso9797 插件，但你可以通过一些原生代码（如Dart、Kotlin、Swift）与原生平台（Android和iOS）的库进行交互来实现这一功能。

以下是一个简化的示例，展示如何在Flutter项目中通过 MethodChannel 与原生平台交互，调用 iso9797 加密算法。为了简化，这里假设你已经有一个实现了 iso9797 加密算法的Android和iOS库。

1. 设置Flutter项目

首先，创建一个新的Flutter项目或在现有项目中添加以下代码。

2. 创建MethodChannel

在 lib 文件夹下的 main.dart 文件中，创建一个 MethodChannel 来与原生平台通信。

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  static const platform = MethodChannel('com.example.iso9797');

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('ISO9797 Encryption Example'),
        ),
        body: Center(
          child: ElevatedButton(
            onPressed: _encryptData,
            child: Text('Encrypt Data'),
          ),
        ),
      ),
    );
  }

  Future<void> _encryptData() async {
    try {
      String plainText = "Hello, Flutter!";
      String result = await platform.invokeMethod('encrypt', plainText);
      print("Encrypted Text: $result");
    } on PlatformException catch (e) {
      print("Failed to encrypt data: '${e.message}'.");
    }
  }
}

3. 在Android中实现ISO9797加密

在 android/app/src/main/java/com/example/your_project_name/ 目录下，创建一个新的Java类，例如 Iso9797Encryptor.java，并在其中实现ISO9797加密算法。

package com.example.your_project_name;

import android.content.Context;
import androidx.annotation.NonNull;

import io.flutter.embedding.engine.plugins.FlutterPlugin;
import io.flutter.embedding.engine.plugins.activity.ActivityAware;
import io.flutter.embedding.engine.plugins.activity.ActivityPluginBinding;
import io.flutter.plugin.common.MethodCall;
import io.flutter.plugin.common.MethodChannel;
import io.flutter.plugin.common.MethodChannel.MethodCallHandler;
import io.flutter.plugin.common.MethodChannel.Result;

// 假设你有一个ISO9797的Java库
// import com.example.iso9797library.Iso9797EncryptorLibrary;

public class Iso9797Encryptor implements FlutterPlugin, MethodCallHandler, ActivityAware {
    private MethodChannel channel;
    private Context applicationContext;

    @Override
    public void onAttachedToEngine(@NonNull FlutterPluginBinding flutterPluginBinding) {
        channel = new MethodChannel(flutterPluginBinding.getBinaryMessenger(), "com.example.iso9797");
        channel.setMethodCallHandler(this);
        applicationContext = flutterPluginBinding.getApplicationContext();
    }

    @Override
    public void onMethodCall(@NonNull MethodCall call, @NonNull Result result) {
        if (call.method.equals("encrypt")) {
            String plainText = call.argument("text");
            try {
                // 使用你的ISO9797库进行加密
                // String encryptedText = Iso9797EncryptorLibrary.encrypt(plainText);
                String encryptedText = "Encrypted:" + plainText; // 这是一个示例，请替换为实际的加密逻辑
                result.success(encryptedText);
            } catch (Exception e) {
                result.error("UNAVAILABLE", e.getMessage(), null);
            }
        } else {
            result.notImplemented();
        }
    }

    @Override
    public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {
        channel.setMethodCallHandler(null);
    }

    @Override
    public void onAttachedToActivity(ActivityPluginBinding binding) {
        // No-op
    }

    @Override
    public void onDetachedFromActivityForConfigChanges() {
        // No-op
    }

    @Override
    public void onReattachedToActivityForConfigChanges(ActivityPluginBinding binding) {
        // No-op
    }

    @Override
    public void onDetachedFromActivity() {
        // No-op
    }
}

别忘了在 android/app/src/main/kotlin/com/example/your_project_name/MainActivity.kt 或 MainActivity.java 中注册这个插件：

import io.flutter.embedding.android.FlutterActivity;
import io.flutter.embedding.engine.FlutterEngine;
import io.flutter.plugins.GeneratedPluginRegistrant;
import com.example.your_project_name.Iso9797Encryptor;

public class MainActivity extends FlutterActivity {
    @Override
    public void configureFlutterEngine(FlutterEngine flutterEngine) {
        super.configureFlutterEngine(flutterEngine);
        new Iso9797Encryptor().onAttachedToEngine(flutterEngine.getDartExecutor().getBinaryMessenger());
        GeneratedPluginRegistrant.registerWith(flutterEngine);
    }
}

4. 在iOS中实现ISO9797加密

在 ios/Runner/ 目录下，打开 AppDelegate.swift 并添加与原生ISO9797库交互的代码（假设你已经有一个实现了ISO9797的Objective-C或Swift库）。

import UIKit
import Flutter

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
    GeneratedPluginRegistrant.register(with: self)
    
    let controller : FlutterViewController = window?.rootViewController as! FlutterViewController
    let channel = FlutterMethodChannel(name: "com.example.iso9797", binaryMessenger: controller)
    
    channel.setMethodCallHandler({
      (call: FlutterMethodCall, result: @escaping FlutterResult) in
      
      guard call.method == "encrypt" else {
        result(FlutterMethodNotImplemented)
        return
      }
      
      guard let text = call.arguments as? String else {
        result(FlutterError(code: "INVALID_ARGUMENT", message: "Text argument not provided", details: nil))
        return
      }
      
      // 使用你的ISO9797库进行加密
      // let encryptedText = YourISO9797Library.encrypt(text)
      let encryptedText = "Encrypted:\(text)" // 这是一个示例，请替换为实际的加密逻辑
      
      result(encryptedText)
    })
    
    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }
}

总结

上述代码展示了如何在Flutter项目中通过 MethodChannel 与原生平台交互，实现ISO9797加密算法。你需要根据实际的ISO9797库替换示例中的加密逻辑。同时，确保在 Info.plist 和 AndroidManifest.xml 中添加必要的权限和配置（如果有）。