Xcode - Not append new data to an array

Milad
May 22, 2021
164 views
0 votes
2 Answers

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")
    }
}

Answers

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

- Yrb
- May 22, 2021 at 2:48 am
- 0 votes
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.
Login or Signup to reply.

Please signup or login to give your own answer.

Click here to cancel reply.

Xcode – Not append new data to an array

Answers