SwiftUI - ForEach with Stride

问题

Im trying to create a list of Hstack'd cards, That is to say, I want to create a scroll view of a series of rows. Each row would contain an HStack of two views displayed side by side, and initialized by some list data structure.

struct MyHStackView: View { 

    var myArray = [SomeStruct(1), SomeStruct(3), SomeStruct(4), SomeStruct(5), SomeStruct(6)]

    var body: some View {
        ScrollView(.vertical) { 
            VStack { 
                ForEach(0..<self.myArray.count) { index in 
                    HStack { 
                        SubView(myArray[index])
                        SubView(myArray[index+1]) 
            }
        } 
    }
}

The only issue is my current implementation touches every element of the array, is there a stride function built into the new ForEach so that I can index on every other element on the array to initialize the row? How would you approach this?

回答1:

If just every other , you may try

  VStack { 
            ForEach(0 ..< self.myArray.count/2) { index in 
                HStack { 
                    SubView(myArray[index * 2])
                    SubView(myArray[index * 2 + 1]) 
        }

Otherwise, you may need to use stride function:

    ForEach( Array(stride(from: 0, to: self.myArray.count, by: 2)), id: \.self) { index in

回答2:

For simple use-cases the solution posted by E. Coms may work. If you plan on modifying or re-ordering the list, it may give you trouble since the id specified is the same as the index and List won't be able to correctly animate removals/additions/re-ordering.

I would create a data-structure to represent the tuple in an identifiable manner:

struct SomeStructTouple: Identifiable {
  let a: SomeStruct
  let b: SomeStruct

  var id: String {
    "\(a.id)-\(b.id)"
  }
}

and then create an array of touples to generate the list.

来源：https://stackoverflow.com/questions/59548909/swiftui-foreach-with-stride

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