How can I pass Content into a function that will return a swiftUI Container view?

Question

mikeTheDad OP

Created Jun ’20

Replies 4

Boosts 0

Views 3k

Participants 3

I'm attempting to create a function that will return a swiftUI container. Something like this:

Code Block     func myStack(content: Text) -> some View {
        ZStack{
            if self.shouldBeHorizontal() {
                HStack(alignment: .center, spacing: 10, content: {content})
            } else {
                VStack(alignment: .center, spacing: 10, content: {content})
            }
        }
    }

However, I really want toe content input to be more generic.
When I change the function declaration to

Code Block     func myStack(content: ZStack) -> some View {

The compiler seems to require me to specify the details of the content of the ZStack.
Alternatively, when I try this:

Code Block     func myStack(content: () -> Content) -> some View {

It complains that Content is an undeclared type.

any/all help greatly appreciated.
thanks,
Mike

Answered by OOPer in 612236022

You can make your method explicitly generic.

Please try something like this:

Code Block     func myStack<Content: View>(content: Content) -> some View {
        ZStack{
            if self.shouldBeHorizontal() {
                HStack(alignment: .center, spacing: 10, content: {content})
            } else {
                VStack(alignment: .center, spacing: 10, content: {content})
            }
        }
    }

or this:

Code Block     func myStack<Content: View>(@ViewBuilder content: ()->Content) -> some View {
        ZStack{
            if self.shouldBeHorizontal() {
                HStack(alignment: .center, spacing: 10, content: content)
            } else {
                VStack(alignment: .center, spacing: 10, content: content)
            }
        }
    }

Boost

Answer 1

Qwily OP

Jun ’20

Try to use AnyView() this way:

Code Block swiftstruct ContentView: View {
  var body: some View {
    self.myStack(content: AnyView(Text("hello")))
  }
  func myStack(content: AnyView) -> some View {
    ZStack{
      if false {
        HStack(alignment: .center, spacing: 0) {
          content
        }
      } else {
        VStack(alignment: .center, spacing: 0) {
          content
        }
      }
    }
  }
}

0

Answer 2

OOPer OP

Jun ’20

Accepted Answer

You can make your method explicitly generic.

Please try something like this:

Code Block     func myStack<Content: View>(content: Content) -> some View {
        ZStack{
            if self.shouldBeHorizontal() {
                HStack(alignment: .center, spacing: 10, content: {content})
            } else {
                VStack(alignment: .center, spacing: 10, content: {content})
            }
        }
    }

or this:

Code Block     func myStack<Content: View>(@ViewBuilder content: ()->Content) -> some View {
        ZStack{
            if self.shouldBeHorizontal() {
                HStack(alignment: .center, spacing: 10, content: content)
            } else {
                VStack(alignment: .center, spacing: 10, content: content)
            }
        }
    }

2

Answer 3

mikeTheDad OP

Jun ’20

Thanks OOPer, your reply was exactly what I was looking for.
Any chance you can refer me to Swift Syntax documentation explaining in general what <Content: View> is?

0

Answer 4

OOPer OP

Jun ’20

(Seems new dev forums has lost the functionality to make replies put on another reply...)

Any chance you can refer me to Swift Syntax documentation explaining in general what <Content: View> is?

It is described in the section Type Constraints of Generics in the Swift book.

0