複数の非同期処理が終わった後に、画面の更新を行い最新の値を表示する方法

Question

前提・実現したいこと

SwiftUIを利用してアプリを開発しています。

データの編集を行い、複数の非同期処理が終わった後に画面の更新をし、確実に新しい値を表示したいです。

---

対象の仕様は以下のとおりです。

• １．エンドポイント①にGETで接続し1番目の値を取得する

• ２、エンドポイント②にGETで接続し１の動作で取得した１番目の値を引数として渡す。

　もともと設定させている２番目の値との合計をクロージャーを使い設定する

• ３、エンドポイント③にPUTで接続し、1番目の値を更新する

• ４，３で新しくした値を利用し、２の動作を行い更新後の１番目の値と２番目の値の合計を取得し表示したい

発生している問題

上記の１，２、３の動作までは正しく動くのですが、４の動作の時に最新の値が表示されません。

該当のソースコード

BaseView.swift

import SwiftUI

struct BaseView: View {
    
    @EnvironmentObject var appState: AppState
    @State var totalNumber:Int = 0
    
    var body: some View {
        VStack{
            VStack{
                Text("The first number:(appState.firstNumber!.firstNumber)") // 1.2の動作後10を表示 -> ３の動作後20を表示
                Divider()
                Text("The total number:(totalNumber)") // 1.2の動作後30を表示 -> ３の動作後30を表示（40と表示したい） 
            }
            .sheet(isPresented: $appState.isSheet,onDismiss: {
                
                appState.getFirstNumber()
                appState.getTotalNumber(firstNumber: appState.firstNumber!.firstNumber,  total: {returnData in
                    self.totalNumber = returnData
                })
            })
            {
                Sheet()
            }
        } .onAppear(){
            appState.getFirstNumber() // 1の動作

            appState.getTotalNumber(firstNumber: appState.firstNumber!.firstNumber,  total: {returnData in
                self.totalNumber = returnData
            }) //2の動作
        }
    }
}

JosonModel.swift

import Foundation

struct FirstNumber:Codable {
    var firstNumber:Int
}

struct SecondNumber:Codable {
    var secondNumber:Int
}

AppState.swift

class AppState: ObservableObject {

@Published var firstNumber:FirstNumber?
@Published var secondNumber:SecondNumber?

@Published var isSheet:Bool = false


func getFirstNumber(){
    // Set up the URL request
    let endpoint: String = "https://sample.com/api/first_nuber/"
    
    guard let url = URL(string: endpoint) else {
        print("Error: cannot create URL")
        return
    }
    let urlRequest = URLRequest(url: url)
    // set up the session
    let config = URLSessionConfiguration.default
    let session = URLSession(configuration: config)
    
    // make the request
    let task = session.dataTask(with: urlRequest) {
        (data, response, error) in
        // check for any errors
        guard error == nil else {
            print("error calling GET")
            print(error!)
            return
        }
        // make sure we got data
        guard let responseData = data else {
            print("Error: did not receive data")
            return
        }
        // parse the result as JSON, since that's what the API provides
        DispatchQueue.main.async {
            do{ self.firstNumber = try JSONDecoder().decode(FirstNumber.self, from: responseData)
            }catch{
                print("Error: did not decode")
                return
            }
        }
    }
    task.resume()
}

func getTotalNumber(firstNumber:Int,total:@escaping(Int)->Void ){
//        print("makeGetCallTotalTemp")
                    
        // Set up the URL request
        let endpoint: String = "https://sample.com/api/total_number/"
        
        guard let url = URL(string: endpoint) else {
            print("Error: cannot create URL")
            return
        }
    let urlRequest = URLRequest(url: url)
        // set up the session
        let config = URLSessionConfiguration.default
        let session = URLSession(configuration: config)
        
        // make the request
        let task = session.dataTask(with: urlRequest) {
            (data, response, error) in
            // check for any errors
            guard error == nil else {
                print("error calling GET")
                return
            }
            // make sure we got data
            guard let responseData = data else {
                print("Error: did not receive data")
                return
            }
            // parse the result as JSON, since that's what the API provides
            DispatchQueue.main.async {
                do{ self.secondNumber = try JSONDecoder().decode(SecondNumber.self, from: responseData)
                   
                    let totalNumber = firstNumber + self.secondNumber!.secondNumber
                    print(self.secondNumber!.secondNumber) // 20
                    total(totalNumber)
                    
                }catch{
                    print("Error: did not decode")
                    return
                }
            }
        }
        task.resume()
    
}


func makeUpDateFirstNumber(firstNumber:Int,finish:@escaping(Bool)->Void) {
    var isFinish:Bool = false

    let endpoint: String = "https://sample.com/api/first_number/"
    
    guard let url = URL(string: endpoint) else {
        print("Error: cannot create URL")
        return
    }
    var urlRequest = URLRequest(url: url)
    urlRequest.httpMethod = "PUT"
    urlRequest.addValue("application/json; charset=utf-8", forHTTPHeaderField: "Content-Type")
    let newInfo:[String:Any]=["firstNumber": firstNumber]
    let jsonInfo: Data
    do {
        jsonInfo = try JSONSerialization.data(withJSONObject: newInfo, options: [])
        urlRequest.httpBody = jsonInfo
    } catch {
        print("Error: cannot create JSON from newInfo")
        return
    }
    let session = URLSession.shared
    let task = session.dataTask(with: urlRequest) {
        (data, response, error) in
        guard error == nil else {
            print("error calling Put")
            return
        }
        guard let responseData = data else {
            print("Error: did not receive data")
            return
        }
        guard let response = response as? HTTPURLResponse else {
            print("Error: did not response data")
            return
        }
        print("The response code is (response.statusCode)")
        // parse the result as JSON, since that's what the API provides
        do {
            guard (try JSONSerialization.jsonObject(with: responseData,
                                                    options: []) as? [String: Any]) != nil else {
                print("Could not get JSON from responseData as dictionary")
                return
            }
        } catch  {
            print("error parsing response from PUT")
            return
        }
        DispatchQueue.main.async {
            isFinish = true
            finish(isFinish)
        }
    }
    task.resume()
}
}

Sheet.swift

import SwiftUI

struct Sheet: View {
    
    @EnvironmentObject var appState: AppState
    @State var isFinish:Bool = false
    
    @Environment(.presentationMode) var presentationMode
    
    var body: some View {
        Button(action:{
            appState.makeUpDateFirstNumber(firstNumber: 20, finish: {returnData in
                isFinish = returnData
            } // 3の動作
            )
        }){
            Text("UPDATE")
        }.onChange(of: isFinish){ result in
            if result {
                self.presentationMode.wrappedValue.dismiss()
            }
        }
    }
}

補足情報（FW/ツールのバージョンなど）

Xcode:Version 12.0.1