swift - Sheet `Implicitly Unwrapped Optional` - Stack Overflow

How come the sheet throws an Implicitly Unwrapped Optional error when the button is pressed? To me it looks like I'm assigning selectedNumber to i and then using it in the sheet, is there a step I'm missing where selectedNumber is reset to nil?

import SwiftUI

struct ContentView: View {
@State private var selectedNumber: Int?
@State private var isShowingSheet = false
    var body: some View {
        ForEach(0..<10) { i in
            Button("\(i)") {
                selectedNumber = i
                isShowingSheet = true
            }
        }
        .sheet(isPresented: $isShowingSheet) {
            Text("\(selectedNumber!)")
        }
    }
}

And when I move the sheet inside the loop to make the i variable accessible it only shows 0

struct ContentView: View {
@State private var isShowingSheet = false
    var body: some View {
        ForEach(0..<10) { i in
            Button("\(i)") {
                isShowingSheet = true
            }
            .sheet(isPresented: $isShowingSheet) {
                Text("\(i)")
            }
        }
    }
}

How come the sheet throws an Implicitly Unwrapped Optional error when the button is pressed? To me it looks like I'm assigning selectedNumber to i and then using it in the sheet, is there a step I'm missing where selectedNumber is reset to nil?

import SwiftUI

struct ContentView: View {
@State private var selectedNumber: Int?
@State private var isShowingSheet = false
    var body: some View {
        ForEach(0..<10) { i in
            Button("\(i)") {
                selectedNumber = i
                isShowingSheet = true
            }
        }
        .sheet(isPresented: $isShowingSheet) {
            Text("\(selectedNumber!)")
        }
    }
}

And when I move the sheet inside the loop to make the i variable accessible it only shows 0

struct ContentView: View {
@State private var isShowingSheet = false
    var body: some View {
        ForEach(0..<10) { i in
            Button("\(i)") {
                isShowingSheet = true
            }
            .sheet(isPresented: $isShowingSheet) {
                Text("\(i)")
            }
        }
    }
}

• swift
• swiftui

Share Improve this question Follow edited Jan 2 at 23:58 malhal 31k77 gold badges123123 silver badges150150 bronze badges asked Jan 2 at 21:36 The-WolfThe-Wolf 8577 bronze badges 2

• 1 You could consider using sheet(item:onDismiss:content:) instead, with selectedNumber as the item. – Benzy Neez Commented Jan 2 at 21:42
• @BenzyNeez thank you, I wasn't aware this existed – The-Wolf Commented Jan 2 at 21:51

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1 Answer 1

Sorted by: Reset to default 0

The solution, as proposed by @BenzyNeez, was to use sheet(item:onDismiss:content:) instead, with selectedNumber as the item.