Creating a form

Paul Hudson    @twostraws    November 8th 2021

Many apps require users to enter some sort of input – it might be asking them to set some preferences, it might be asking them to confirm where they want a car to pick them up, it might be to order food from a menu, or anything similar.

SwiftUI gives us a dedicated view type for this purpose, called Form. Forms are scrolling lists of static controls like text and images, but can also include user interactive controls like text fields, toggle switches, buttons, and more.

You can create a basic form just by wrapping the default text view inside Form, like this:

var body: some View {
    Form {
        Text("Hello, world!")
            .padding()
    }
}

If you’re using Xcode’s canvas, you’ll see it change quite dramatically: before Hello World was centered on a white screen, but now the screen is a light gray, and Hello World appears in the top left in white.

You can remove the padding too – we’ll come back to that later:

Form {
    Text("Hello, world!")
}

What you’re seeing here is the beginnings of a list of data, just like you’d see in the Settings app. We have one row in our data, which is the Hello World text, but we can add more freely and have them appear in our form immediately:

Form {
    Text("Hello, world!")
    Text("Hello, world!")
    Text("Hello, world!")
}

In fact, you can have as many things inside a form as you want, although if you intend to add more than 10 SwiftUI requires that you place things in groups to avoid problems.

For example, this code shows ten rows of text just fine:

Form {
    Text("Hello, world!")
    Text("Hello, world!")
    Text("Hello, world!")
    Text("Hello, world!")
    Text("Hello, world!")
    Text("Hello, world!")
    Text("Hello, world!")
    Text("Hello, world!")
    Text("Hello, world!")
    Text("Hello, world!")
}

But this attempts to show 11, which is not allowed:

Form {
    Text("Hello, world!")
    Text("Hello, world!")
    Text("Hello, world!")
    Text("Hello, world!")
    Text("Hello, world!")
    Text("Hello, world!")
    Text("Hello, world!")
    Text("Hello, world!")
    Text("Hello, world!")
    Text("Hello, world!")
    Text("Hello, world!")
}

Tip: In case you were curious why 10 rows are allowed but 11 is not, this is a limitation in SwiftUI: it was coded to understand how to add one thing to a form, how to add two things to a form, how to add three things, four things, five things, and more, all the way up to 10, but not beyond – they needed to draw a line somewhere. This limit of 10 children inside a parent actually applies everywhere in SwiftUI.

If you wanted to have 11 things inside the form you should put some rows inside a Group:

Form {
    Group {
        Text("Hello, world!")
        Text("Hello, world!")
        Text("Hello, world!")
        Text("Hello, world!")
        Text("Hello, world!")
        Text("Hello, world!")
    }

    Group {
        Text("Hello, world!")
        Text("Hello, world!")
        Text("Hello, world!")
        Text("Hello, world!")
        Text("Hello, world!")
    }
}

Groups don’t actually change the way your user interface looks, they just let us work around SwiftUI’s limitation of ten child views inside a parent – that’s text views inside a form, in this instance.

If you want your form to look different when splitting items into chunks, you should use the Section view instead. This splits your form into discrete visual groups, just like the Settings app does:

Form {
    Section {
        Text("Hello, world!")
    }

    Section {
        Text("Hello, world!")
        Text("Hello, world!")
    }
}

There’s no hard and fast rule when you should split a form into sections – it’s just there to group related items visually.

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