Can't ForEach an array in a Dictionary

Question

Created Jun ’20

Replies 3

Boosts 0

Views 6.1k

Participants 4

I have an array of "Groups" in a dictionary defined with [String: [AnyObject]]
I am trying to do a ForEach with this array in a SwiftUI View but getting: Cannot convert value of type 'String' to expected argument type 'Range<Int>' and Referencing initializer 'init(_:content:)' on 'ForEach' requires that '[String : [AnyObject]]' conform to 'Identifiable'
My code is:

Code Block 		var body: some View {
				NavigationView {
						List {
								ForEach(user.groups["groups"]) {	group in
								}
						}
				}
		}

Boost

Answer 1

OOPer OP

Jun ’20

Please show more context. I cannot reproduce the same errors with your code.
Please do not forget to include whole definition of your user. And please clarify, are you using Xcode 12 beta?

0

Answer 2

Claude31 OP

Jun ’20

Some other points

user.groups["groups"] is an optional. Cannot be used as is, need to unwrap

Should probably add , id: \.self in ForEach

The following runs oK:

Code Block struct ContentView: View {
    var users : [String: [AnyObject]] = ["groups" : ["1", "2"] as [AnyObject]]
		var body: some View {
				NavigationView {
						List {
								ForEach(users["groups"]! as! [String], id: \.self) {		group in
										Text("Hello \(group)")
								}
						}
				}
		}
}

0

Answer 3

Developer Tools Engineer OP

Apple

Jun ’20

The values passed to ForEach need to have an ID. There are two ways to achieve this:

Make the elements of the Arrays in your Dictionary be of a type conforming to Identifiable. (AnyObject doesn’t.)
Provide a KeyPath to the id: parameter which specifies how to retrieve the ID. (You won’t be able to get a KeyPath from AnyObject.)

You’ve probably noticed a common theme: AnyObject is not going to work for this. You need to specify a more specific type and then make sure ForEach knows how to get an ID from that type.

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