如何连接 Swift 文件和 dart 文件？

Question

我正在连接 Flutter 和 Swift，以便我可以通过连接仅在 Swift 中工作的公共证书 API 在 Flutter 中使用它。但是，我有一个问题，我想问一个问题。

我想要做的是通过一个通道将一个 Swift 函数导入到 main.dart 中，以便在 main.dart 中按下按钮时 Swift 代码可以工作

如何将 Tilko.swift 中的 func 转换为 main.dart

这是结构 enter image description here

main.dart 位于 ios/lib 文件夹，Tilko.swift 位于 ios/Runner

Answer 1

应该有一个FlutterMethodChannel.swift 它看起来像

class MethodChannelFlutter {
    var controller: FlutterViewController
    var printerChannel: FlutterMethodChannel
    init(controller: FlutterViewController) {
        self.controller = controller
        printerChannel = FlutterMethodChannel(name: "hem_cert_copy_plugin", binaryMessenger: controller.binaryMessenger)

        printerChannel.setMethodCallHandler {
            (call: FlutterMethodCall, _: @escaping FlutterResult) -> Void in
             //Your handler
             //...

你的 AppDelegate.swift 应该是这样的

import UIKit
import Flutter

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
    override func application(
        _ application: UIApplication,
        didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
    ) -> Bool {
        
        let controller : FlutterViewController = window?.rootViewController as! FlutterViewController
         MethodChannelFlutter(controller: controller)
        
        GeneratedPluginRegistrant.register(with: self)
        return super.application(application, didFinishLaunchingWithOptions: launchOptions)
    }
}

Answer 2

我在这里创建了一个工作示例 https://github.com/theamorn/flutter-template

在这个文件中，我有 3 种连接到 Native SDK 的方式

1. 立即调用 Native 并返回值
2. 调用 Native 并传递给函数并从该函数返回
3. 调用 Native 并等待委托回调，以便我们可以回调到 Flutter

首先你在 iOS 中添加 Flutter Channel https://github.com/theamorn/flutter-template/blob/main/ios/Runner/AppDelegate.swift

private func initFlutterChannel() {
  // com.theamorn.flutter can change to whatever you want, just have to be the same between Flutter and iOS and unique ‘domain prefix. just com.theamorn is not enough
  if let controller = window?.rootViewController as? FlutterViewController {
    let channel = FlutterMethodChannel(
        name: methodChannel,
        binaryMessenger: controller.binaryMessenger)
    
    channel.setMethodCallHandler({ [weak self] (
        call: FlutterMethodCall,
        result: @escaping FlutterResult) -> Void in
        switch call.method {
        case "methodNameOne":
            if let data = call.arguments as? String {
                self?.callNativeSDK(data)
            } else {
                result(FlutterMethodNotImplemented)
            }
        case "deviceHasPasscode":
            result(self?.isDeviceHasPasscode)
            
        case "returnValue":
            if let data = call.arguments as? String {
                self?.returnValueSDK(result: result, id: data)
            } else {
                result(FlutterMethodNotImplemented)
            }
        default:
            result(FlutterMethodNotImplemented)
        }
    })
  }
}

methodNameOne 用于调用 Native 函数，其名称应在 Flutter 中保持一致

private func callNativeSDK(_ id: String) {
    // You can put any Native SDK in here, if the result return from Delegate
    let sdk = ThirdPartySDK(delegate: self, id: id)
    sdk.start()
}

private func returnValueSDK(result: FlutterResult, id: String) {
    // You can call any SDK in here if the result return immediately
    let sdk = ThirdPartySDK(delegate: self, id: id)
    return result(sdk.process())
}

使用这个从 Flutter 调用 https://github.com/theamorn/flutter-template/blob/main/lib/main.dart

final channel = MethodChannel('com.theamorn.flutter');
try {
    await channel.invokeMethod('methodNameOne', "12345");
} on PlatformException catch (e) {
    debugPrint("==== Failed to get data '${e.message}' ====");
}

从 Native 回调到 Flutter，我在 mocking SDK 的 Delegate 中调用这个函数

extension AppDelegate: ThirdPartySDKDelegate {
    
    func onFinish(value: String) {
        // You can send anything into arguments, String, Boolean, or even Dictionary
        // Send data back to Flutter
        if let controller = self.window?.rootViewController as? FlutterViewController {
            let channel = FlutterMethodChannel(
                name: methodChannel,
                binaryMessenger: controller.binaryMessenger)
            channel.invokeMethod("methodNameTwoFromSDK", arguments: value)
        }
    }
    
}

等待来自 Native 的值

_waitingDataFromNative() async {
    channel.setMethodCallHandler((call) async {
      // Receive data from Native
      switch (call.method) {
        case "methodNameTwoFromSDK":
          _nativeValue = call.arguments;
          setState(() {});
          break;
        default:
          break;
      }
    });
  }

您在 iOS 中看到该方法名称，Flutter 需要完全相同，否则它们无法看到彼此。