Structs vs classes in iOS Swift - UI Rendering Compared

Component - Structs vs classes

This UI component shows a simple Swift app screen comparing structs and classes. It displays two sections side by side: one for a struct example and one for a class example. Each section has a title and a short description. A button below each section lets you create a new instance and see how it behaves differently.

Widget Tree

VStack
├── HStack
│   ├── VStack (Struct Section)
│   │   ├── Text ("Struct")
│   │   ├── Text ("Value type, copied on assignment")
│   │   └── Button ("Create Struct")
│   └── VStack (Class Section)
│       ├── Text ("Class")
│       ├── Text ("Reference type, shared instance")
│       └── Button ("Create Class")
└── Text ("Tap buttons to see behavior")

The main vertical stack holds two horizontal sections side by side. Each horizontal section is a vertical stack with a title, description, and a button. Below the horizontal stack is a text instruction. This layout visually compares structs and classes with interactive buttons.

Render Trace - 11 Steps

Step 1: VStack

Step 2: HStack

Step 3: VStack (Struct Section)

Step 4: Text (Struct Title)

Step 5: Text (Struct Description)

Step 6: Button (Struct)

Step 7: VStack (Class Section)

Step 8: Text (Class Title)

Step 9: Text (Class Description)

Step 10: Button (Class)

Step 11: Text (Instruction)

State Change - Re-render

Trigger:User taps 'Create Struct' or 'Create Class' button

Before

No instance created, no message shown

→

After

Shows a message below buttons describing instance behavior (copy for struct, shared reference for class)

Re-renders:The message text area below the buttons re-renders to show the new message

UI Quiz - 3 Questions

What happens visually when you tap the 'Create Struct' button?

A The whole screen reloads

B A message appears showing the struct instance is copied

C The button color changes to red

D Nothing changes on screen

Key Insight

Using clear side-by-side sections with titles, descriptions, and interactive buttons helps beginners visually compare structs and classes. Showing state changes only in a small message area keeps the UI simple and focused.