antigravity-skills-reference/skills/swiftui-ui-patterns/references/loading-placeholders.md

Loading & Placeholders

Use this when a view needs a consistent loading state (skeletons, redaction, empty state) without blocking interaction.

Patterns to prefer

• Redacted placeholders for list/detail content to preserve layout while loading.
• ContentUnavailableView for empty or error states after loading completes.
• ProgressView only for short, global operations (use sparingly in content-heavy screens).

Recommended approach

1. Keep the real layout, render placeholder data, then apply .redacted(reason: .placeholder).
2. For lists, show a fixed number of placeholder rows (avoid infinite spinners).
3. Switch to ContentUnavailableView when load finishes but data is empty.

Pitfalls

• Don’t animate layout shifts during redaction; keep frames stable.
• Avoid nesting multiple spinners; use one loading indicator per section.
• Keep placeholder count small (3–6) to reduce jank on low-end devices.

Minimal usage

VStack {
  if isLoading {
    ForEach(0..<3, id: \.self) { _ in
      RowView(model: .placeholder())
    }
    .redacted(reason: .placeholder)
  } else if items.isEmpty {
    ContentUnavailableView("No items", systemImage: "tray")
  } else {
    ForEach(items) { item in RowView(model: item) }
  }
}