DataStorage.swift 

class DataStorage: ObservableObject {
    @Published var cartArray = [Order]()
}

ViewModel.swift
 
class ViewModel : ObservableObject{
     var dataStorage = DataStorage()
     @Published var bookOptionsArray = [BookOption]()

  func addBook (bookId:String ,bookName : String){
       dataStorage.cartArray.append(Order(bookId:bookId, bookName: bookName, bookoptions:self.bookOptionsArray))
}



View1:

struct View1: View {
    @ObservedObject var vwModel = ViewModel()
    @EnvironmentObject var datastrg: DataStorage
    ListView(vwModel:vwModel)
}

 struct ListView: View{
     @ObservedObject var vwModel = ViewModel()
     @EnvironmentObject var dt: DataStorage 
        List(vwModel.bookoptions.bookList) {opn in

         //Display List
         //If a book a selected it will add to bookOptionsArray of viewModel. Call addBook() in ViewModel class
}

}


View3 

struct View3: View {
    @EnvironmentObject var dt : DataStorage
     List(dt.cartArray){item in
    //Display the selected books to place order
}

View3 displays empty List ,because cartArray is not stored properly How to display List in View3 ? Any ideas/ suggestions will be helpful

CodePudding user response：

You are not calling your function addBook anywhere, add an onappear to your view3 calling the function and your list will populate with data.

CodePudding user response：

You are creating a local DataStorage in your view model instead of using the one in the @EnvironmentObject so instead inject it into the view model.

First change the view model so you must inject DataStorage

class ViewModel: ObservableObject {
    var dataStorage: DataStorage
    //...

    init(dataStorage: DataStorage) {
        self.dataStorage = dataStorage
    }
    //...
}

Then change View1 so you create the view model in an init

struct View1: View {
    @ObservedObject var vwModel: ViewModel
    @EnvironmentObject var datastrg: DataStorage

    init() {
        vwModel = ViewModel(dataStorage: datastrg)
    }
    //...
}