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Xcode – Not append new data to an array

I want to add new data to a list in my project
but I can’t do it

I have a ContentView.swift view for showing products list
and in another view (ShopView) I want to add data to products array
My products array and my addProduct() function
in the Products.swift file

Please help me
Thanks

ContentView.swift

struct ContentView: View {
    @ObservedObject var cart = Products()
    
    var body: some View {
        NavigationView{
            List {
                ForEach(cart.products) { product in
                    Text("(product.name) (product.price)$")
                }
            }
            .navigationBarItems(
                trailing: NavigationLink(destination: Shop()) {
                    Text("Go Shop")
                })
            .navigationBarTitle("Cart")
        }
    }
}

Product.swift

struct Product: Identifiable {
    var id = UUID()
    var name: String
    var price: Int
}

Shop.swift

struct Shop: View {
    @ObservedObject var cart = Products()
    
    var body: some View {
        VStack{
            Button("Add Product To Cart") {
                cart.addProduct(product: Product(name: "Name", price: 399))
            }
        }
    }
}

Products.swift

class Products: ObservableObject {
    @Published var products = [Product]()
    
    func addProduct(product: Product) {
        products.append(product)
        print("Product Added")
    }
}
Tags:

2

Answers


  1. 0

    Right now, you’re creating two different instances of Products. If you want the data to be shared, you have to use the same instance.

    struct ContentView: View {
    @ObservedObject var cart = Products()
    
    var body: some View {
        NavigationView{
            List {
                ForEach(cart.products) { product in
                    Text("(product.name) (product.price)$")
                }
            }
            .navigationBarItems(
                trailing: NavigationLink(destination: Shop(cart: cart)) {  //<-- HERE
                    Text("Go Shop")
                })
            .navigationBarTitle("Cart")
        }
    }
}


struct Shop: View {
    @ObservedObject var cart : Products //<-- HERE
    
    var body: some View {
        VStack{
            Button("Add Product To Cart") {
                cart.addProduct(product: Product(name: "Name", price: 399))
            }
        }
    }
}

    Another way to achieve this type of functionality is by using an environment object. Additional reading on that approach: https://www.hackingwithswift.com/quick-start/swiftui/how-to-use-environmentobject-to-share-data-between-views

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  2. 0

    I think you will find the simplest implementation will be to define your model as:

    class Products: ObservableObject {
    //Implement a shared resource here
    public static let shared = Products()

    // I would also make the published var name something different then the class name.
    // Otherwise you will be calling a lot of products.products.
    // Or you could change the name of the class to "Cart"
    @Published var products: [Product] = []
    
    func addProduct(product: Product) {
        products.append(product)
        print("Product Added")
    }
}

    Use it in your structs with:
    @ObservedObject var cart = Products.shared

    This will give you one common shared Products class. You don’t have to worry about passing is around between views.

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