SwiftUI Random Element

Question

I followed the instructions at https://developer.apple.com/documentation/swift/array/2994747-randomelement that give this example

let names = ["Zoey", "Chloe", "Amani", "Amaia"]
let randomName = names.randomElement()!
// randomName == "Amani"

This won't work as randomName is not initialised so I tried a workaround:

   let words = [
    "anbieten","anbietend","angeboten"]

 var  random : String { words.randomElement()!}

to give some context I am using this random variable for a game that should display the same word 3 times so I need to be able to be sure that the value of "random" contains yes a random word from the array but always the same random one.

Unfortunately when I use the variable in SwiftUI

  NavigationLink(destination: ResultView(choice: "Arial")) {
                    Text("\(random)").font(.custom("Arial", size: 60))
                }
                
                NavigationLink(destination: ResultView(choice: "San Francisco")) {
                    Text("\(random)").font(.system(size: 60))
                }

it obviously show two different elements of the array.

I did try to change my random as per example in the apple developer site to a let

let  random : String { words.randomElement()!}

but this returns

 let' declarations cannot be computed properties

Dharman · Accepted Answer · 2020-07-18 23:13:41Z

You can't have it be a computed property because, as you saw, it wouldn't be consistent. What you want is a constant (i.e., let), but as you saw, you can't have a constant computed property (if you think about it, it doesn't really make sense for something to both "be the same every time" [constant] and "be recomputed every time" [computed property]). Instead, you want to be doing basically what you did in your first code listing:

let names = ["Zoey", "Chloe", "Amani", "Amaia"]
let randomName = names.randomElement()!

You said that this didn't work because randomName wasn't initialized. I assume you were trying it in this context:

struct MyView: View {
    let names = ["Zoey", "Chloe", "Amani", "Amaia"]
    let randomName = names.randomElement()!

    var body: some View {
        MyOtherView()
    }
}

and it wasn't working. To fix that problem, simply define an initializer like so: (you can add any other parameters that you need to the initializer as well)

struct MyView: View {
    let names = ["Zoey", "Chloe", "Amani", "Amaia"]
    let randomName: String

    init() {
        self.randomName = names.randomElement()!
    }

    var body: some View {
        MyOtherView()
    }
}

note: if you have any @Binding variables that you were passing to this view, you may be a little confused on how to include them in your initializer, so here's a brief example:

struct SuperView: View {
    @State var text: String = ""

    var body: some View {
        SubView(text: self.$text)
    }
}

struct SubView: View {
    @Binding var text: String
    let names = ["Zoey", "Chloe", "Amani", "Amaia"]
    let randomName: String

    init(text: Binding<String>) {
        self._text = text // this accesses the raw Binding<String> variable, allowing you to use the passed value
        self.randomName = names.randomElement()!
    }

    var body: some View {
        SomeOtherView()
    }
}

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