Stepper in iOS Swift - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ ui_behavior

intermediate

Stepper Value Change Behavior

What will be the value displayed after tapping the stepper increment button twice starting from 0?

iOS Swift

import SwiftUI

struct ContentView: View {
  @State private var value = 0

  var body: some View {
    VStack {
      Stepper("Value: \(value)", value: $value)
    }
  }
}

A Value: 3

B Value: 1

C Value: 0

D Value: 2

💡 Hint

Each tap on the increment button increases the value by 1.

The stepper starts at 0. Each tap increments the value by 1. After two taps, the value is 2.

📝 Syntax

intermediate

Correct Stepper Initialization

Which option correctly initializes a Stepper with a value bound to a state variable and a range from 1 to 5?

A Stepper(value: value, in: 1...5) { Text("Value: \(value)") }

B Stepper($value, range: 1...5) { Text("Value: \(value)") }

C Stepper(value: $value, in: 1...5) { Text("Value: \(value)") }

D Stepper(value: $value, range: 1..5) { Text("Value: \(value)") }

💡 Hint

The value parameter requires a binding and the range uses three dots for closed range.

Option C uses the correct syntax: value bound with $, and range 1...5 (closed range).

❓ lifecycle

advanced

Stepper Value Binding Effect

What happens if you remove @State from the variable bound to the Stepper's value?

iOS Swift

import SwiftUI

struct ContentView: View {
  private var value = 0

  var body: some View {
    Stepper("Value: \(value)", value: $value)
  }
}

A Compilation error because $value requires a binding to a @State variable.

B Stepper works normally and updates the value on tap.

C Runtime crash due to uninitialized binding.

D Stepper displays but value never changes.

💡 Hint

Bindings require a property wrapper like @State to work.

Without @State, value is a simple variable, so $value binding is invalid and causes a compile error.

❓ navigation

advanced

Stepper in NavigationView Behavior

Inside a NavigationView, what happens if you place a Stepper inside a Form and update its value?

iOS Swift

import SwiftUI

struct ContentView: View {
  @State private var count = 0

  var body: some View {
    NavigationView {
      Form {
        Stepper("Count: \(count)", value: $count)
      }
      .navigationTitle("Stepper Demo")
    }
  }
}

A NavigationView hides the Stepper and shows only the title.

B Stepper updates count and UI refreshes inside the form with navigation title visible.

C Stepper does not update count because Form disables state changes.

D App crashes due to Stepper inside NavigationView.

💡 Hint

Form supports interactive controls and NavigationView shows navigation bar.

Stepper works normally inside Form and NavigationView. The count updates and UI refreshes with the navigation title shown.

🔧 Debug

expert

Unexpected Stepper Behavior Debugging

Why does this Stepper not update the displayed value when tapped?

iOS Swift

import SwiftUI

struct ContentView: View {
  @State private var value = 0

  var body: some View {
    VStack {
      Stepper("Value: \(value)", value: $value)
      Text("Current value is \(value)")
    }
  }
}

A The code is correct; the value updates and UI refreshes as expected.

B The Text view does not update because value is not marked @State.

C The Stepper updates value but the UI does not refresh because the view is not reactive.

D The Stepper is missing a range, so it does not update value.

💡 Hint

Check if the @State property and bindings are used correctly.

The code correctly uses @State and binding. Stepper updates value and Text shows updated value. UI refreshes automatically.