Error handling for network calls in iOS Swift - UI Render Trace

Component - Error handling for network calls

This UI component shows how an iOS app handles errors during network calls. It displays a loading state, shows data when the call succeeds, and shows an error message with a retry button if the call fails.

Widget Tree

View
├── VStack
│   ├── Text (statusMessage)
│   └── Button (Retry)

The main view contains a vertical stack (VStack). Inside it, there is a Text widget that shows the current status or error message. Below the text, there is a Retry button that appears only when there is an error.

Render Trace - 4 Steps

Step 1: View

Step 2: VStack

Step 3: Text

Step 4: Button

State Change - Re-render

Trigger:Network call fails and sets error state

Before

statusMessage = 'Loading...', error = nil

→

After

statusMessage = 'Failed to load data. Please try again.', error = some error

Re-renders:Entire VStack re-renders to update Text and show Retry button

UI Quiz - 3 Questions

What does the Text widget show when the network call is loading?

A "Loading..."

B "Failed to load data. Please try again."

C "Retry"

D Empty text

Key Insight

Handling network errors in mobile apps requires showing clear messages and giving users a way to retry. Using a simple vertical layout with conditional button visibility helps keep the UI clean and responsive to state changes.