Is it possible to delete an item from Coredata using onTapGesture?

Question

robevans OP

Created Nov ’20

Replies 4

Boosts 0

Views 1.9k

Participants 3

I know about .onDelete modifier, but say I want to remove an item from Coredata using onTapGesture is that possible?

Code Block          .onDelete { indexSet in
          let deleteItem = self.isFavorite[indexSet.first!]
          self.managedObjectContext.delete(deleteItem)
          do {
            try self.managedObjectContext.save()
          }catch {
            print(error)
          }
        }

I tried doing

Code Block          .onTapGesture { indexSet in
          let deleteItem = self.isFavorite[indexSet.first!]
          self.managedObjectContext.delete(deleteItem)
          do {
            try self.managedObjectContext.save()
          }catch {
            print(error)
          }
        }

But that didn't go well.

Boost

Answer 1

DelawareMathGuy OP

Nov ’20

hi,

the .onDelete modifier is usually something you add to a ForEach, as in

Code Block List {
  ForEach(items) { item in
    Text(item.name)
  } 
    .onDelete(perform: yourDeleteFunction)
}

the .onTapGesture is something you would add to a view associated with an item in the list, within the scope of the ForEach:

Code Block List {
  ForEach(items) { item in
    Text(item.name)
      .onTapGesture({ doSomething(to: item) }) // doSomething could certainly delete this item
  } 
}

(i think that's right and) hope that helps,
DMG

0

Answer 2

robevans OP

Nov ’20

Thanks, this sort of helps. I sort of knew the difference between the two, but struggling to know the proper index in coredata.

0

Answer 3

robevans OP

Nov ’20

So here's where I'm getting hung up. I created a function in the view and then call removeFavorite, but the compiler fails.

Code Block @Environment(\.managedObjectContext) var managedObjectContext
 @FetchRequest(fetchRequest: FavoriteItem.getAllFavorites()) var favorites:FetchedResults<FavoriteItem>
  func removeFavorite(at offsets: IndexSet) {
    for item in offsets {
      let favorite = favorites[item]
      managedObjectContext.delete(favorite)
    }
  }

Code Block                    Text("Foo")
                    .onTapGesture(perform: removeFavorite)

0

Answer 4

BabyJ OP

Nov ’20

I think you want your onTapGesture more like this where it’s directly deleting the item from the ForEach.

Code Block SwiftList {
	ForEach(0 ..< items.count) { index in
		Text(items[index].name)
			.onTapGesture {
				let favorite = favorites[index]
				managedObjectContext.delete(favorite)
			}
	}
}

0