const final sampleChannel = MethodChannel('com.example.toybox')

sampleChannel.invokeMethod('getBattery')

let controller: FlutterViewController = window?.rootViewController as! FlutterViewController

final arguments = {'name': 'John'}

guard let args = call.arguments as? [String: String] else {return}
let name = args["name"]

・code → String
　　・An error code.
・details → dynamic
　　・Error details, possibly null.
・message → String?
　　・A human-readable error message, possibly null.
・stacktrace → String?
　　・Native stacktrace for the error, possibly null.

  static const squareChannel = MethodChannel('kiosk.flutter/square');

    final arguments = <String, dynamic>{
      'price': 140,
      'memo': 'test',
      'disablesKeyedInCardEntry': true,
    };

    final transactionID =
        await squareChannel.invokeMethod<String?>('openSquare', arguments);

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

import '../../widgets/app_scaffold.dart';

final transactionProvider =
    StateProvider.autoDispose<String>((ref) => 'No Transaction Yet');

class SampleScreen extends ConsumerWidget {
  const SampleScreen({super.key});

  static const squareChannel = MethodChannel('kiosk.flutter/square');
  @override
  Widget build(BuildContext context, WidgetRef ref) {
    return AppScaffold(
      color: Colors.grey,
      body: Stack(
        children: [
          Center(
            child: Text(
              ref.watch(transactionProvider),
              style: const TextStyle(
                fontSize: 18,
                fontWeight: FontWeight.bold,
              ),
            ),
          ),
          Align(
            alignment: const Alignment(0, 0.7),
            child: ElevatedButton(
              style: ElevatedButton.styleFrom(
                shape: const StadiumBorder(),
              ),
              onPressed: () => _openSquareReaderPayment(ref),
              child: const Text('OPEN SQUARE'),
            ),
          ),
        ],
      ),
    );
  }

  Future<void> _openSquareReaderPayment(
    WidgetRef ref,
  ) async {
    final arguments = <String, dynamic>{
      'price': 140,
      'memo': 'test',
      'disablesKeyedInCardEntry': true,
    };
    final transactionID =
        await squareChannel.invokeMethod<String?>('openSquare', arguments);

    ref
        .read(transactionProvider.notifier)
        .update((state) => 'Success with $transactionID');
  }
}

import UIKit
import Flutter
import SquarePointOfSaleSDK

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {

    private var final_result: FlutterResult?

  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
      let controller : FlutterViewController = window?.rootViewController as! FlutterViewController

      let squareChannel = FlutterMethodChannel(name:"kiosk.flutter/square", binaryMessenger: controller.binaryMessenger)

      squareChannel.setMethodCallHandler({
        (call: FlutterMethodCall, result: @escaping FlutterResult)-> Void in
        guard call.method == "openSquare" else {
          result(FlutterMethodNotImplemented)
          return
        }
          
          let parameters = call.arguments as! Dictionary<String, Any>
          if let price = parameters["price"] as? Int,
             let memo=parameters["memo"] as? String,
             let disablesKeyedInCardEntry = parameters["disablesKeyedInCardEntry"] as? Bool{
              self.openSquare(result: result, price:price, memo:memo, disablesKeyedInCardEntry: disablesKeyedInCardEntry)
          }else{
              print("パラメータの型が不正です")
              result(FlutterMethodNotImplemented)
              return
          }
      })

    GeneratedPluginRegistrant.register(with: self)
    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }

let callbackURL = URL(string: "xxxxx://")!

        var amount: SCCMoney?
        do{
            // 支払い金額の設定
            amount = try SCCMoney(amountCents: price, currencyCode: "JPY")
        }catch {
            // エラーハンドリング
        }

    SCCAPIRequest.setApplicationID("xxxxxxxxxxxxxxx")

        var request: SCCAPIRequest?
        do{
            request = try SCCAPIRequest(callbackURL: callbackURL,
                                        amount:amount!,
                                        userInfoString: memo, // 注文番号
                                        locationID: nil,
                                        notes:memo,
                                        customerID: nil,
                                        supportedTenderTypes: .all, // 支払い方法の設定
                                        clearsDefaultFees: true, // ???
                                        returnsAutomaticallyAfterPayment: true,
                                        disablesKeyedInCardEntry: disablesKeyedInCardEntry,
                                        skipsReceipt: true
            )
        }catch{
            // エラーハンドリング
        }

        var success = false
        do{
            try SCCAPIConnection.perform(request!)
            success = true
        }catch let error as NSError{
            print(error.localizedDescription)
        }

            if let error = response.error as NSError? {
                // Handle a failed request.
                print("Error: \(error.localizedDescription)")
            }

    private func openSquare(result:@escaping FlutterResult, price: Int, memo: String, disablesKeyedInCardEntry: Bool){
        final_result = result
        
        let callbackURL = URL(string: "square-sample://")!
        
        var amount: SCCMoney?
        do{
            // 支払い金額の設定
            amount = try SCCMoney(amountCents: price, currencyCode: "JPY")
        }catch {
            // エラーハンドリング
        }
        
        SCCAPIRequest.setApplicationID("xxxxxxxxxxxxxxxxxxx")

        var request: SCCAPIRequest?
        do{
            request = try SCCAPIRequest(callbackURL: callbackURL,
                                        amount:amount!,
                                        userInfoString: memo, // 注文番号
                                        locationID: nil,
                                        notes:memo,
                                        customerID: nil,
                                        supportedTenderTypes: .all, // 支払い方法の設定
                                        clearsDefaultFees: true, // ???
                                        returnsAutomaticallyAfterPayment: true,
                                        disablesKeyedInCardEntry: disablesKeyedInCardEntry,
                                        skipsReceipt: true
            )
        }catch{
            // エラーハンドリング
        }
        
        // var success = false
        do{
            try SCCAPIConnection.perform(request!)
            // success = true
        }catch let error as NSError{
            print(error.localizedDescription)
        }
        
        
    }
    
    override func application(_ app:UIApplication, open url: URL, options:[UIApplication.OpenURLOptionsKey: Any]=[:])-> Bool{
        
        // guard SCCAPIResponse.isSquareResponse(url)else{return false}
        
        // var decodeError: Error?
        
        do{
            let response = try SCCAPIResponse(responseURL: url)
            
            if let error = response.error{
                // Handle a failed request.
                print("Error: \(error.localizedDescription)")
            }
            // Print checkout object
            print("Transaction successful: \(response)")
            final_result?(response.transactionID)
            return true
        }catch let error as NSError{
            // Handle unexpected errors.
            print(error.localizedDescription)
        }

        return false
    }
}