Does code at 04:41 compile?

Question

dan101 OP

Created Jun ’23

Replies 1

Boosts 2

Participants 2

The code for @State doesn't seem to work.

 struct DonutListView: View {
    var donutList: DonutList
    @State private var donutToAdd: Donut?
 
    var body: some View {
        List(donutList.donuts) { DonutView(donut: $0) }
        Button("Add Donut") { donutToAdd = Donut() }
            .sheet(item: $donutToAdd) { // <-- would need a "donut in"
                TextField("Name", text: $donutToAdd.name) // <-- donutToAdd is optional and I'm not sure how it would be unwrapped
                Button("Save") {
                    donutList.donuts.append(donutToAdd)
                    donutToAdd = nil
                }
                Button("Cancel") { donutToAdd = nil }
            }
    }
}

Does anyone have a fix for this?

Thanks, Dan!

Boost

Answer 1

William NYC OP

May ’24

I wish Apple would test their code before presenting at a conference.
I added a name state variable for the TextField.

  
@State private var name: String = ""
...
            .sheet(item: $donutToAdd) { _ in
                TextField("Name", text: $name)
                .padding(10)
                .overlay(
                    RoundedRectangle(cornerRadius: 20)
                        .stroke(Color.black)
                )
                Button("Save") {
                    if let donutToAdd {
                        donutToAdd.name = name
                        donutList.donuts.append(donutToAdd )
                        self.donutToAdd = nil
                        self.name = ""
                    }
                }
                Button("Cancel") { self.donutToAdd = nil }
            }
 
code-block

And DonutList needs to be a class (else you get a mutating member on immutable value).

 @Observable
    class DonutList {
        var donuts: [Donut]
        
        init(donuts: [Donut]) {
            self.donuts = donuts
        }
    }
code-block

0

	struct DonutListView: View {
	var donutList: DonutList
	@State private var donutToAdd: Donut?

	var body: some View {
	List(donutList.donuts) { DonutView(donut: $0) }
	Button("Add Donut") { donutToAdd = Donut() }
	.sheet(item: $donutToAdd) { // <-- would need a "donut in"
	TextField("Name", text: $donutToAdd.name) // <-- donutToAdd is optional and I'm not sure how it would be unwrapped
	Button("Save") {
	donutList.donuts.append(donutToAdd)
	donutToAdd = nil
	}
	Button("Cancel") { donutToAdd = nil }
	}
	}
	}


	@State private var name: String = ""
	...
	.sheet(item: $donutToAdd) { _ in
	TextField("Name", text: $name)
	.padding(10)
	.overlay(
	RoundedRectangle(cornerRadius: 20)
	.stroke(Color.black)
	)
	Button("Save") {
	if let donutToAdd {
	donutToAdd.name = name
	donutList.donuts.append(donutToAdd )
	self.donutToAdd = nil
	self.name = ""
	}
	}
	Button("Cancel") { self.donutToAdd = nil }
	}

	code-block

	@Observable
	class DonutList {
	var donuts: [Donut]

	init(donuts: [Donut]) {
	self.donuts = donuts
	}
	}
	code-block