How to have a dynamic List of Views using SwiftUI

Question

I can do a static List like

List {    View1()    View2() } 

But how do i make a dynamic list of elements from an array? I tried the following but got error: Closure containing control flow statement cannot be used with function builder 'ViewBuilder'

    let elements: [Any] = [View1.self, View2.self]      List {        ForEach(0..<elements.count) { index in           if let _ = elements[index] as? View1 {              View1()           } else {              View2()           }     } } 

Is there any work around for this? What I am trying to accomplish is a List contaning dynamic set of elements that are not statically entered.

Answer 1

Looks like the answer was related to wrapping my view inside of AnyView

struct ContentView : View {     var myTypes: [Any] = [View1.self, View2.self]     var body: some View {         List {             ForEach(0..<myTypes.count) { index in                 self.buildView(types: self.myTypes, index: index)             }         }     }          func buildView(types: [Any], index: Int) -> AnyView {         switch types[index].self {            case is View1.Type: return AnyView( View1() )            case is View2.Type: return AnyView( View2() )            default: return AnyView(EmptyView())         }     } } 

With this, i can now get view-data from a server and compose them. Also, they are only instanced when needed.

Answer 2

if/let flow control statement cannot be used in a @ViewBuilder block.

Flow control statements inside those special blocks are translated to structs.

e.g.

if (someBool) {     View1() } else {     View2() } 

is translated to a ConditionalValue<View1, View2>.

Not all flow control statements are available inside those blocks, i.e. switch, but this may change in the future.

More about this in the function builder evolution proposal.

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In your specific example you can rewrite the code as follows:

struct ContentView : View {      let elements: [Any] = [View1.self, View2.self]      var body: some View {         List {             ForEach(0..<elements.count) { index in                 if self.elements[index] is View1 {                     View1()                 } else {                     View2()                 }             }         }     } }