Toggle switch in iOS Swift - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ ui_behavior

intermediate

Toggle switch state change effect

What will be the text displayed in the label after toggling the switch from OFF to ON?

iOS Swift

import SwiftUI

struct ContentView: View {
  @State private var isOn = false

  var body: some View {
    VStack {
      Toggle("Enable Feature", isOn: $isOn)
      Text(isOn ? "Feature is ON" : "Feature is OFF")
    }
    .padding()
  }
}

A Toggle is enabled

B Feature is OFF

C Feature is ON

D No text is displayed

💡 Hint

The label text changes based on the toggle's boolean state.

The toggle changes the isOn state from false to true. The Text view shows "Feature is ON" when isOn is true.

❓ lifecycle

intermediate

Toggle switch initial state in UIKit

In UIKit, if you create a UISwitch programmatically and do not set its state, what is the default state of the switch when it appears?

A Random state each time

B OFF (false)

C Undefined, causes a crash

D ON (true)

💡 Hint

Think about the default boolean value for UISwitch's isOn property.

UISwitch defaults to OFF (isOn = false) if not explicitly set.

📝 Syntax

advanced

Correct SwiftUI Toggle binding syntax

Which option correctly binds a Toggle to a @State variable named isEnabled?

iOS Swift

import SwiftUI

struct MyView: View {
  @State private var isEnabled = false

  var body: some View {
    // Toggle code here
  }
}

A Toggle("Enable", isOn: $isEnabled)

B Toggle("Enable", isOn: Binding(isEnabled))

C Toggle("Enable", isOn: isEnabled)

D Toggle("Enable", isOn: Binding($isEnabled))

💡 Hint

Use the $ prefix to pass a binding to the Toggle.

The $ prefix creates a binding to the @State variable, which Toggle requires.

🔧 Debug

advanced

Why does the UISwitch not update the label?

Given this UIKit code, why does the label not update when the switch is toggled? let toggle = UISwitch() let label = UILabel() func setup() { toggle.addTarget(self, action: #selector(switchChanged), for: .valueChanged) } @objc func switchChanged() { label.text = toggle.isOn ? "ON" : "OFF" } // toggle and label are added to the view What is the most likely reason?

A The addTarget method is called after the switch is toggled

B The switchChanged method is not marked @objc

C The toggle's isOn property does not change automatically

D The label is not added to the view hierarchy

💡 Hint

If the label is not visible, text changes won't show.

If the label is not added to the view, updating its text has no visible effect.

🧠 Conceptual

expert

Accessibility for Toggle switches

Which practice best improves accessibility for a toggle switch in SwiftUI?

A Add .accessibilityLabel("Enable feature") to the Toggle

B Use a Text view instead of Toggle for better screen reader support

C Disable the toggle to prevent accidental changes

D Set the toggle color to red for visibility

💡 Hint

Accessibility labels help screen readers describe controls.

Adding .accessibilityLabel provides a clear description for users relying on assistive technologies.