如何将数据从数组查询传递到视图文件？

Question

Hi there!

Since my last question was poorly described and not really a question, I've decided to re-brand my question.

What is my question?

What is the best way to pass an array from my Firestore Database to my view file from my model file? Is my approach even correct?

My current approach

Essentially three files are used to create the output. The code I used was from another function that does work, though it is a different query.

1. Friends_Requests.swift (View file)

import SwiftUI
import Firebase
import FirebaseFirestore

struct Friends_Requests: View {
    @State var goBack: Bool = false
    @ObservedObject var friends_model = Friends_Model()

    
    var body: some View {
        if !goBack {
            VStack {
                
                Group{
                    Text("Your Friend Requests")
                        .font(.title)
                        .fontWeight(.bold)
                    Divider()
                }
                
                Spacer()
                List (friends_model.friend_requests) { item in
                    Text(item)
                }
                .refreshable{
                    friends_model.getFriendRequestData()
                    
                }
                .listStyle(.plain)
                
                
                Spacer()
                
                Group {
                    HStack{
                        Text("Friends requests will appear here")
                    }
                }
                
                
                Group {
                    Divider()
                    HStack {
                        Button(action: {
                            withAnimation {
                                self.goBack.toggle()
                            }
                        }) {
                            Image(systemName: "arrow.left.circle.fill")
                                .resizable()
                                .frame(width: 40, height: 40)
                        }
                        .padding(.leading, 20)
                        Spacer()
                    }
                }
            }
        } else if goBack {
            FriendsPanel()
        }
    }

struct Friends_Requests_Previews: PreviewProvider {
    static var previews: some View {
        Friends_Requests()
    }
}
}

2. Friends_Model.swift (View model)

import Foundation
import Firebase
import FirebaseFirestore
import SwiftUI


class Friends_Model: ObservableObject {
 
    @Published var friend_requests = [Friends_Requests_Data]()

    
    
    func getFriendRequestData() {
        let db = Firestore.firestore()
        
        let user = Auth.auth().currentUser
        let email = user?.email ?? "error: email"
        
        let queryRef = db.collection("users").document(email)
        
        queryRef.getDocument { snapshot, error in
            
            //check for errors
            if error == nil {
                print("no errors")
                
                if let snapshot = snapshot {
                    
                                
                    self.friend_requests = snapshot.get("friendRequests") { d in
                        
                            //Create friend item for each document
                            return Friends_Requests_Data(id: d.documentID,
                                                email: d["friendRequests"] as? String ?? "")
                    }
                                
            } else {
                // handle error
            }
            
        }
        
        
    }
}

3. Friends_Requests_Data.swift (Data model)

import Foundation

struct Friends_Requests_Data: Identifiable {
    var id: String
    var email: String
}

What error's am I getting?

• Friends_Requests.swift (View file)

• Friends_Model.swift (View model)

Answer 1

I did it!

Thanks to the help of the users above I managed to get the whole thing working.

I changed my View model function to look like this (Friends_Model.swift) :

func getFriendRequestData() {
        let db = Firestore.firestore()
        
        let user = Auth.auth().currentUser
      
        let email = user?.email ?? "error: email"
        
        let queryRef = db.collection("users").whereField("friendRequests", arrayContains: email)
        
        queryRef.getDocuments { snapshot, error in
            
            //check for errors
            if error == nil {
                print("no errors")
                
                if let snapshot = snapshot {
                    
                    //Update the list property in main thread
                    //DispatchQueue.main.async {
                        //get all docs and create friend list
                        
                            self.friend_requests = snapshot.documents.map { d in
                                    //Create friend item for each document
                                return Friends_Requests_Data(id: d.documentID,
                                                        friendRequests: d["email"] as? String ?? "")
                                
                            }
                    //}
                }
                
            } else {
                // handle error
            }
            
        }
        
        
    }

I also changed this in my view (Friends_Requests.swift) :

• Added init to call the function

init() {
        friends_model.getFriendRequestData()
}

• Changed (Old)

    List (friends_model.friend_requests) { item in
                        Text(item)
    }

(New)

    List (friends_model.friend_requests) { item in
                        Text(item.friendRequests)
    }