flutter_mercadopago/ios/Classes/SwiftFlutterMercadopagoPlugin.swift

import Flutter
import UIKit
import MercadoPagoSDK

public class SwiftFlutterMercadopagoPlugin: NSObject, FlutterPlugin, PXLifeCycleProtocol {

  var pendingResult: FlutterResult?

  public static func register(with registrar: FlutterPluginRegistrar) {
    let channel = FlutterMethodChannel(name: "flutter_mercadopago", binaryMessenger: registrar.messenger())
    
    let instance = SwiftFlutterMercadopagoPlugin()
    registrar.addMethodCallDelegate(instance, channel: channel)
  }

  public func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
    if (call.method == "getPlatformVersion") {
      result("iOS " + UIDevice.current.systemVersion)
    } else if (call.method == "MercadoPagoStartForPayment") {
      let args = call.arguments as! Dictionary<String, String>
      let publicKey = args["publicKey"] ?? ""
      let preferenceId = args["preferenceId"] ?? ""
      
      pendingResult = result
      
      startCheckout(publicKey: publicKey, preferenceId: preferenceId)
    } else {
      handleNavigationBar(isMercadoPagoActive: false)
      result(FlutterMethodNotImplemented)
    }
  }

  private func startCheckout(publicKey: String, preferenceId: String) {
    let checkout = MercadoPagoCheckout.init(builder: MercadoPagoCheckoutBuilder.init(publicKey: publicKey, preferenceId: preferenceId))
    
    handleNavigationBar(isMercadoPagoActive: true)
    checkout.start(navigationController: controller(), lifeCycleProtocol: self)
  }
  
  public func cancelCheckout() -> (() -> Void)? {
    return {
      self.pendingResult!("-1")
      
      self.handleNavigationBar(isMercadoPagoActive: false)
    }
  }
  
  public func finishCheckout() -> ((PXResult?) -> Void)? {
    return ({(_ result: PXResult?) in
      self.pendingResult!(result?.getPaymentId() ?? "")
      self.handleNavigationBar(isMercadoPagoActive: false)
    })
  }
  
  private func handleNavigationBar(isMercadoPagoActive: Bool) {
    if (isMercadoPagoActive) {
      controller().navigationBar.isHidden = false
    } else {
      controller().popToRootViewController(animated: true)
      controller().navigationBar.isHidden = true
    }
  }
  
  private func controller() -> UINavigationController {
    let rootViewController = UIApplication.shared.keyWindow?.rootViewController
    return rootViewController as! UINavigationController
  }

}