Errors in ForEach SwiftUI

Question

Created Apr ’21

Replies 3

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Views 3.2k

Participants 2

Hello
I get errors in ForEach that I don't know how to solve:

Generic struct 'ForEach' requires that 'Main' conform to 'RandomAccessCollection'
Unable to infer type of a closure parameter 'user' in the current context

Error at line 30 - 31

Code:

Code Block //
//  ContentView.swift
//  ARWeather
//
//  Created by Jad Taljabini on 08/04/21.
//
import SwiftUI
import Combine
struct ContentView: View {
    
    @EnvironmentObject var networkController: NetworkControllerItalia
    var body: some View {
        NavigationView {
            Form{
                TextField("Input city name", text: $networkController.cityName, onEditingChanged: { te_xt in
                    networkController.url = URL(string: "https://api.openweathermap.org/data/2.5/weather?q=\(networkController.cityName)&appid=") ?? URL(string: "https://www.apple.com")!
                    networkController.fun()
                }, onCommit: {
                    withAnimation{
                        networkController.url = URL(string: "https://api.openweathermap.org/data/2.5/weather?q=\(networkController.cityName)&appid=") ?? URL(string: "https://www.apple.com")!
                        networkController.fun()
                    }
                })
                Section {
                    ForEach(networkController.users.weather ?? [], id: \.self){ user in
                        Text(user.main ?? "")
                    }
                    ForEach(networkController.users.main ?? Main(temp: 0), id: \.self){ user in
                        Text("\(user.temp)")
                    }
                }
            }
        }
    }
}
class NetworkControllerItalia: ObservableObject {
    private var can: AnyCancellable?
    @Published var cityName: String = ""
    @Published var users = UserItalia(weather: [])
    var url = URL(string: "https://www.apple.com")!
    
    func fun(){
        self.can = URLSession.shared.dataTaskPublisher(for: url)
            .map { $0.data }
            .decode(type: UserItalia.self, decoder: JSONDecoder())
            .eraseToAnyPublisher()
            .receive(on: DispatchQueue.main)
            .sink(receiveCompletion: {completion in
                print(completion)
            }, receiveValue: { users in
                self.users  = users
            })
    }//Funzione che riempe users di dati da internet
}
struct UserItalia: Decodable, Hashable{
    var weather: [Weather]?
    var main: Main?
}
struct Weather: Decodable, Hashable {
    var main: String?
}
struct Main: Decodable, Hashable {
    var temp: Float
}

The JSON API is like this:

Code Block {    "coord": {
        "lon": -0.1257,
        "lat": 51.5085
    },
    "weather": [
        {
            "id": 801,
            "main": "Clouds",
            "description": "few clouds",
            "icon": "02d"
        }
    ],
    "base": "stations",
    "main": {
        "temp": 285.45,
        "feels_like": 283.96,
        "temp_min": 284.82,
        "temp_max": 285.93,
        "pressure": 1021,
        "humidity": 47
    },
    "visibility": 10000,
    "wind": {
        "speed": 5.66,
        "deg": 220
    },
    "clouds": {
        "all": 20
    },
    "dt": 1617888145,
    "sys": {
        "type": 1,
        "id": 1414,
        "country": "GB",
        "sunrise": 1617859180,
        "sunset": 1617907473
    },
    "timezone": 3600,
    "id": 2643743,
    "name": "London",
    "cod": 200
}

Thank you

Answered by Claude31 in 670021022

That's the problem with such complex definitions in your code…

There is probably a missing parenthesis before .temp (to be balanced by another leading one.

Code Block Text( "\(( networkController.users.main ?? Main(temp: 0)).temp)")

Boost

Answer 1

Claude31 OP

Apr ’21

I don't understand what you want to show in Section and what you do in ForEach.

In addition, your naming of var is awfully confusing

main used in different places for different things
users as plural but not an array…
weather singular but several values in array

If I understand what you want to do, you should probably:

Code Block Section {
     ForEach(networkController.users.weather ?? [], id: \.self){ userWeather in  // rename user
     Text(userWeather.main ?? "")
   }
   // ForEach is meaningless here ForEach(networkController.users.main ?? Main(temp: 0), id: \.self){ user in
    //  Text("\(user.temp)")
   Text( "\(networkController.users.main ?? Main(temp: 0)).temp)")
}

0

Answer 2

Jad-T OP

Apr ’21

Text( "\(networkController.users.main ?? Main(temp: 0).temp)")

Gives some errors:

Cannot convert value of type 'Float' to expected argument type 'Main'
Instance method 'appendInterpolation' requires that 'Main' conform to '_FormatSpecifiable'

But yes, (this: Text( "\(networkController.users.main ?? Main(temp: 0).temp)")), this is what I want to do.

0

Answer 3

Claude31 OP

Apr ’21

Accepted Answer

That's the problem with such complex definitions in your code…

There is probably a missing parenthesis before .temp (to be balanced by another leading one.

Code Block Text( "\(( networkController.users.main ?? Main(temp: 0)).temp)")

0