[Flutter] ios 메쏘드 채널

const methodChannel = MethodChannel('com.example.myapp/channel');

String response = await methodChannel.invokeMethod('getData');

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 methodChannel = FlutterMethodChannel(name: "com.example.myapp/channel",
                                             binaryMessenger: controller.binaryMessenger)
    methodChannel.setMethodCallHandler({
      [weak self] (call: FlutterMethodCall, result: @escaping FlutterResult) -> Void in
      // Handle method calls
    })

    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }
}

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

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  static const platform = MethodChannel('com.example.myapp/photo');

  String _imagePath = '아직 이미지가 선택되지 않았습니다.';

  Future<void> _getPhoto() async {
    String imagePath;
    try {
      final String result = await platform.invokeMethod('getPhoto');
      imagePath = result;
    } on PlatformException catch (e) {
      imagePath = "사진을 가져오는 데 실패했습니다: '${e.message}'.";
    }

    setState(() {
      _imagePath = imagePath;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Flutter와 iOS 사진 예제'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(_imagePath),
            RaisedButton(
              onPressed: _getPhoto,
              child: Text('사진 선택하기'),
            ),
          ],
        ),
      ),
    );
  }
}

import UIKit
import Flutter
import PhotosUI

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
  private var imageResult: FlutterResult?

  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
    GeneratedPluginRegistrant.register(with: self)

    let controller : FlutterViewController = window?.rootViewController as! FlutterViewController
    let photoChannel = FlutterMethodChannel(name: "com.example.myapp/photo",
                                              binaryMessenger: controller.binaryMessenger)
    photoChannel.setMethodCallHandler({
      [weak self] (call: FlutterMethodCall, result: @escaping FlutterResult) -> Void in
      // Flutter로부터 'getPhoto' 메소드 콜을 받을 때
      if call.method == "getPhoto" {
        self?.imageResult = result
        self?.showPhotoPicker(from: controller)
      } else {
        result(FlutterMethodNotImplemented)
      }
    })

    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }

  private func showPhotoPicker(from controller: UIViewController) {
    var configuration = PHPickerConfiguration()
    configuration.selectionLimit = 1
    configuration.filter = .images

    let picker = PHPickerViewController(configuration: configuration)
    picker.delegate = self
    controller.present(picker, animated: true, completion: nil)
  }
}

extension AppDelegate: PHPickerViewControllerDelegate {
  func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
    picker.dismiss(animated: true, completion: nil)

    guard let result = results.first, result.itemProvider.canLoadObject(ofClass: UIImage.self) else {
      self.imageResult?("사진을 선택하지 않았습니다.")
      return
    }

    result.itemProvider.loadObject(ofClass: UIImage.self) { (object, error) in
      DispatchQueue.main.async {
        if let image = object as? UIImage, let data = image.jpegData(compressionQuality: 1.0), let path = self.saveImageToDocumentDirectory(imageData: data) {
          self.imageResult?(path)
        } else {
          self.imageResult?("이미지를 불러오는 데 실패했습니다.")
        }
      }
    }
  }

  private func saveImageToDocumentDirectory(imageData: Data) -> String? {
    let fileManager = FileManager.default
    let paths = (NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as NSString).appendingPathComponent("temp_image.jpg")
    fileManager.createFile(atPath: paths as String, contents: imageData, attributes: nil)
    return paths
  }
}