Passing List between Views in SwiftUi

Question

I'm making a ToDo list app on my own to try to get familiar with iOS development and there's this one problem I'm having:

I have a separate View linked to enter in a new task with a TextField. Here's the code for this file:

import SwiftUI

struct AddTask: View {
     @State public var task : String = ""
     @State var isUrgent: Bool = false // this is irrelevant to this problem you can ignore it

    
    var body: some View {
        VStack {
            VStack(alignment: .leading) {
                Text("Add New Task")
                    .bold()
                    .font(/*@START_MENU_TOKEN@*/.title/*@END_MENU_TOKEN@*/)
                TextField("New Task...", text: $task)
                Toggle("Urgent", isOn: $isUrgent)
                    .padding(.vertical)
                Button("Add task", action: {"call some function here to get what is 
in the text field and pass back the taskList array in the Content View"})
               
                 
                
            }.padding()
            Spacer()
        }
    }
    
}


struct AddTask_Previews: PreviewProvider {
    static var previews: some View {
        AddTask()
    }
}

So what I need to take the task variable entered and insert it into the array to be displayed in the list in my main ContentView file.

Here's the ContentView file for reference:

import SwiftUI

struct ContentView: View {
    @State var taskList = ["go to the bakery"]
    
    struct AddButton<Destination : View>: View {

        var destination:  Destination

        var body: some View {
            NavigationLink(destination: self.destination) { Image(systemName: "plus") }
        }
    }
    
    var body: some View {
        VStack {
            NavigationView {
                List {
                    ForEach(self.taskList, id: \.self) {
                    item in Text(item)
                    }
                }.navigationTitle("Tasks")
                .navigationBarItems(trailing: HStack { AddButton(destination: AddTask())})
            }
            
        }
        
}
struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
  }
}

I need a function to take the task entered in the TextField, and pass it back in the array in the ContentView to be displayed in the List for the user

-thanks for the help

Answer 1

You can add a closure property in your AddTask as a callback when the user taps Add Task. Just like this:

struct AddTask: View {
  var onAddTask: (String) -> Void // <-- HERE
  @State public var task: String = ""
  @State var isUrgent: Bool = false

  var body: some View {
    VStack {
      VStack(alignment: .leading) {
        Text("Add New Task")
          .bold()
          .font(.title)
        TextField("New Task...", text: $task)
        Toggle("Urgent", isOn: $isUrgent)
          .padding(.vertical)
        Button("Add task", action: {
          onAddTask(task)
        })
      }.padding()
      Spacer()
    }
  }

}

Then, in ContentView:

.navigationBarItems(
    trailing: HStack {
      AddButton(
        destination: AddTask { task in
            taskList.append(task)
        }
      )
  }
)

@jnpdx provides a good solution by passing Binding of taskList to AddTask. But I think AddTask is used to add a new task so it should only focus on The New Task instead of full taskList.