SOLVED: Day 25 - ForEach not working when creating buttons for an array of items – 100 Days of SwiftUI

SOLVED: Day 25 - ForEach not working when creating buttons for an array of items

@lolrie

Jun '23

I'm trying to generate a row buttons for rock, paper, and scissors (3 buttons) using a ForEach loop, but it's not working.

let choices = ["rock", "paper", "scissors"]

HStack {
    ForEach(choices, id: \.self) {
        Button {
            MoveButton(name: $0.capitalized, image: $0)
        }
    }
}

At the ForEach line, I'm getting error:

Contextual type for closure argument list expects 1 argument, which cannot be implicitly ignored. Insert '_ in'

accompanied by this error at the Button line:

Contextual closure type '() -> MoveButton' expects 0 arguments, but 1 was used in closure body

This, however, works

HStack(spacing: 15) {
    ForEach(choices, id: \.self) {
        MoveButton(name: $0.capitalized, image: $0)
    }
}

Writing ForEach using indexes also works

HStack(spacing: 15) {
    ForEach(0..<3) { index in
        Button {
            print("Buttons were generated!")
        } label: {
            MoveButton(name: choices[index].capitalized, image: choices[index])
        }
    }
}

Could someone help me understand why reading directly into the array is causing problems with Button? Thanks!

For context, MoveButton is just a separate view generating button appearance. It's not a button itself (hence why I'm trying to wrap it in a Button).

struct MoveButton: View {
    var name: String
    var image: String

    var body: some View {
        VStack {
            Image(image)
                .resizable()
                .frame(width: 50, height: 50)
                .frame(width: 100, height: 100)
                .background(Color("color-background-alt"))
                .cornerRadius(10)
                .padding(.bottom, 10)
                .shadow(color: .black.opacity(0.15), radius: 5, x: 0, y: 5)

            Text(name)
                .font(.custom("Inter-Medium", size: 14))
        }
    }
}

@roosterboy HWS+

Jun '23

HStack {
    ForEach(choices, id: \.self) {
        Button {
            MoveButton(name: $0.capitalized, image: $0)
        }
    }
}

$0 here refers to the argument to the Button's closure, not the ForEach's. But you aren't passing in anything for $0 to be a reference to. And you use neither an explicit parameter nor a shorthand parameter in your ForEach. Hence the first error message.
Button takes 2 closures, one for the action and one for the label. The action closure takes no arguments, but you are using $0, which indicates there should be an argument. Hence the second error message.

You need to do something like this:

HStack {
    ForEach(choices, id: \.self) { choice in
        Button {
            //whatever the action is supposed to be
        } label: {
            MoveButton(name: choice.capitalized, image: choice)
        }
    }
}

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