SwiftUI: the ForEach view

Sep 23, 2021

Learn how to use the ForEach view in SwiftUI to loop over a range or an array and generate views, including how the id parameter identifies each item.

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The ForEach view in SwiftUI is very useful to iterate over an array, or a range, and generate views that we can use.

For example, here we create 3 Text views that print the numbers from 0 to 2:

ForEach(0..<3) {
    Text("\($0)")
}

$0 means the first argument passed to the closure, which in this case it’s (in order) the number 0, 1, and 2.

In this example I embed them in a VStack otherwise they would overlap:

VStack {
    ForEach(0..<3) {
        Text("\($0)")
    }.padding()
}

VStack with ForEach displaying numbers 0, 1, 2 vertically with padding

Notice how I used the padding() modifier to add some spacing

A common way to use ForEach is inside a List view:

List {
    ForEach(0..<3) {
        Text("\($0)")
    }
}

List view with ForEach displaying numbers 0, 1, 2 as separate rows

This is such a common thing to do that we can actually omit ForEach and iterate directly from List:

List(0..<3) {
    Text("\($0)")
}

List directly iterating over range displaying numbers 0, 1, 2 as rows without explicit ForEach

Those 2 examples used a range 0..<3. We can iterate over an array too:

let fruits = ["Apple", "Pear", "Orange"]

//...

List {
    ForEach(fruits, id: \.self) {
        Text("\($0)")
    }
}

List with ForEach iterating over fruits array displaying Apple, Pear, Orange as separate rows

Notice how in this case we have another parameter: id.

This is to uniquely identify the item in the array.

Using \.self for id works for built-in types, in case you are iterating a custom struct you’ll need that to conform to the Identifiable protocol or provide a unique parameter.

Tagged: Swift · All topics

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