【SwiftUI + SwiftData】ScrollView + LazyVStack vs Large amounts of data 👉 https://android.benigumo.com/20240627/scrollview-lazyvstack-vs-large-amounts-of-data/

ScrollView + LazyVStack vs Large amounts of data.swift

import SwiftUI
import SwiftData

@Model
final class Item {
  var i: Int
  var s: String

  init(i: Int, s: String) {
    self.i = i
    self.s = s
  }
}

struct TestLazyStack: View {
  @Environment(\.modelContext) private var modelContext
  @Query(sort: \Item.s) private var items: [Item]

  private let size = 1_000

  var body: some View {
    ScrollView {
      LazyVStack {
        ForEach(items) { item in
          Text("\(item.i) | \(item.s)")
            .monospaced()
        }
      }
    }
    .onAppear {
      clear()
      generate()
    }
  }

  private func clear() {
    try? modelContext.delete(model: Item.self)
  }

  private func generate() {
    (0 ..< size).forEach { i in
      modelContext.insert(
        Item(i: i, s: String(format: "%04d", i))
      )
    }
  }
}

#Preview {
  let container = try! ModelContainer(for: Schema([Item.self]))
  return TestLazyStack()
    .modelContainer(container)
}