Delete item from a section list on SwiftUI

Question

Overview

im doing a simple app with core data I have two entity users and territory the app shows a list of the users in sections by territory the problem is In the delete action the list delete the user from the first section if I try to delete the second user from the second section it delete the second user from the first section.

I think index set is getting wrong sending the index of the section but when I try to change the onDelete to my nested forEach don't work

Here is the code

import SwiftUI

struct ContentView: View {
    @Environment(\.managedObjectContext) var moc
    @FetchRequest(entity: User.entity(), sortDescriptors: [NSSortDescriptor(keyPath: \User.name, ascending: true)]) var users: FetchedResults<User>
    @FetchRequest(entity: Territory.entity(), sortDescriptors: [NSSortDescriptor(keyPath: \Territory.name, ascending: true)]) var territories: FetchedResults<Territory>
    @State private var showAddUser = false


       var body: some View {
           GeometryReader{ geometry in
               NavigationView {
                   ZStack {

                       List {
                           ForEach(self.territories, id: \.self) { territorie in
                            Section(header: Text(territorie.wrappedName)) {
                                ForEach(territorie.usersArray, id: \.self) { user in
                                    NavigationLink(destination: UserView(user: user)) {
                                        VStack{
                                            HStack{
                                               Text("user")
                                                Spacer()
                                                Text(user.dayLastVisit)
                                                    .padding(.horizontal)
                                            }
                                            HStack {
                                                Text(user.wrappedEmoji)
                                                    .font(.largeTitle)
                                                VStack(alignment: .leading) {
                                                    Text("\(user.wrappedName + " " + user.wrappedLastName)")
                                                        .font(.headline)
                                                    Text(user.wrappedType)

                                                }
                                                Spacer()
                                            }
                                        }

                                    }
                                }.onDelete(perform: self.deleteItem)
                            }
                           }



                       }
                       .listStyle(GroupedListStyle())
                       .environment(\.horizontalSizeClass, .regular)

                       VStack {
                           Button(action:{ self.showAddRUser.toggle()}){
                               ButtonPlus(icon:"plus")}
                           .offset(x: (geometry.size.width * 0.40), y: (geometry.size.height  * 0.38))
                           .sheet(isPresented: self.$showAddUser){
                               NewUserView().environment(\.managedObjectContext, self.moc)
                                  }
                       }
                   }
               .navigationBarTitle("Users")
                   .navigationBarItems( trailing: HStack {
                    EditButton()
                    Button(action:{self.showAddUser.toggle()}){
                    ButtonNew(text:"Nueva")}
                    }

                    .sheet(isPresented: self.$showAddUser){
                        NewUserView().environment(\.managedObjectContext, self.moc)
                   }
                   )

               }
           }
       }
    func deleteItem(at offsets: IndexSet) {
        for offset in offsets { 
            let user = users[offset]

            //borarlo del context
            moc.delete(user)

        }
        try? moc.save()
    }

}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

im learning swift and swiftui so im would appreciate any help

Kevin Renskers · Accepted Answer · 2020-03-06 00:23:56Z

6

You’ll need to pass in a section index as well as the row index, so that you know which nested item to delete. Something like this.

.onDelete { self.deleteItem(at: $0, in: sectionIndex) }

And change your function to accept that section index:

func deleteItem(at offsets: IndexSet, in: Int)

In your case you can probably pass in something like territorie.id as the section index, and use that to delete the correct item. Or pass in the territorie object - whatever you need to get to the correct user. Only the index won’t get you there. Hope it all makes sense!

edited Mar 6, 2020 at 0:23

answered Mar 5, 2020 at 23:50

Kevin Renskers

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2 Comments

Misael Landeros Over a year ago

hi thanks! I have User.id and and Territory.id both UUID and territory have a relationship one to many with User, to pass the territorie.id as the section index I just have to change the .self for the .id?

Misael Landeros Over a year ago

it worked! I just passed the territorie object then instead of the users[offset] I use the territorie.usersArray of the object to delete the correct user

Ivar van Wooning · Accepted Answer · 2020-11-06 13:06:26Z

For me, the solution was the following:

ForEach(self.territories, id: \.self) { territorie in

    Section(header: Text(territorie.wrappedName)) {

        ForEach(territorie.usersArray, id: \.self) { user in
            // your code here
        }
        .onDelete { indexSet in
            for index in indexSet {
                moc.delete(territorie[user])
            }
                
            // update the view context
            moc.save()
        }
    }
}

The index in indexSet returns the item that should be deleted in that specific section. So if I delete the first item of a section, it returns 0.

The territorie returns a list of all the items that are contained in that section. So using territorie[index] will return the specific user object you want to delete.

Now that we have the object we want to delete, we can pass it to moc.delete(territorie[index]). Finally, we save it with moc.save().

Sidenote: although Misael used the variable 'territorie', I prefer to use the variable name section.

David · Accepted Answer · 2021-06-03 16:58:49Z

2

So thanks to the help of Kevin Renskers who found a solution. I just add a .onDelete { self.deleteItem(at: $0, in: territorie)} to my function then I use the same arrayUsers from the territory.

 func deleteItem(at offsets: IndexSet, in ter: Territory) {
        
        for offset in offsets {
             let user =  ter.usersArray[offset] 
            moc.delete(user)
            
        }
        try? moc.save()
    }

edited Jun 3, 2021 at 16:58

David

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answered Mar 7, 2020 at 20:02

Misael Landeros

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