Pull-to-refresh (refreshable) in iOS Swift - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ ui_behavior

intermediate

What happens when you pull down on a SwiftUI List with .refreshable modifier?

Consider a SwiftUI List with the .refreshable modifier added. What is the expected behavior when the user pulls down on the list?

iOS Swift

List(items, id: \.self) { item in
  Text(item)
}
.refreshable {
  await fetchData()
}

A The list crashes because .refreshable is not supported on List.

B The list immediately reloads without calling fetchData(), no indicator is shown.

C Nothing happens because .refreshable requires a button press to activate.

D The list triggers the fetchData() async function and shows a spinning indicator until it completes.

💡 Hint

Think about what .refreshable is designed to do in SwiftUI.

The .refreshable modifier adds pull-to-refresh support to scrollable views like List. When the user pulls down, the async closure runs and a spinner shows until it finishes.

❓ lifecycle

intermediate

When does the refresh closure run in a SwiftUI .refreshable modifier?

In SwiftUI, the .refreshable modifier takes an async closure. When exactly is this closure executed?

iOS Swift

List { ... }
.refreshable {
  await loadData()
}

A Only when the user pulls down far enough to trigger the refresh control.

B Immediately when the view appears on screen.

C Every time the list scrolls up or down.

D When the user taps on any list item.

💡 Hint

Think about user interaction with pull-to-refresh.

The refresh closure runs only when the user pulls down the list far enough to activate the refresh control.

🔧 Debug

advanced

Why does the spinner never stop after pull-to-refresh in this SwiftUI code?

Given this SwiftUI code snippet, the spinner shows but never disappears after pulling to refresh. What is the cause?

iOS Swift

List(items, id: \.self) { item in
  Text(item)
}
.refreshable {
  fetchData()
}

A The List must be inside a ScrollView for refreshable to work.

B The .refreshable modifier requires a synchronous closure.

C fetchData() is not awaited, so the refresh never completes.

D The items array is empty, so the spinner stays indefinitely.

💡 Hint

Check if the async function is awaited properly.

The .refreshable closure expects an async function to be awaited. If fetchData() is not awaited, SwiftUI never knows when refresh ends, so spinner stays.

🧠 Conceptual

advanced

What is the minimum iOS version that supports SwiftUI's .refreshable modifier?

You want to use the .refreshable modifier in your SwiftUI app. Which iOS version must your app target at minimum?

A iOS 15.0

B iOS 14.0

C iOS 13.0

D iOS 16.0

💡 Hint

Check Apple documentation for .refreshable availability.

The .refreshable modifier was introduced in iOS 15.0, so apps must target at least iOS 15 to use it.

❓ navigation

expert

How to programmatically trigger pull-to-refresh in SwiftUI List with .refreshable?

You want to start the refresh spinner and call the refresh closure programmatically without user pulling down. Which approach works best?

A Call the .refreshable closure directly from code using a function reference.

B Use UIKit's UIRefreshControl and integrate it with SwiftUI List via UIViewRepresentable.

C Use a @State boolean to conditionally show a ProgressView above the List and call fetchData() manually.

D Set the List's scroll position to top programmatically to simulate pull-to-refresh.

💡 Hint

SwiftUI does not provide a direct API to trigger .refreshable programmatically.

SwiftUI's .refreshable modifier does not expose a way to start refresh programmatically. Using UIKit's UIRefreshControl bridged via UIViewRepresentable is the common workaround.