Project structure in iOS Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare the main app struct in SwiftUI.

iOS Swift

import SwiftUI

@main
struct MyApp: [1] {
  var body: some Scene {
    WindowGroup {
      ContentView()
    }
  }
}

Drag options to blanks, or click blank then click option'

AScene

BWindowGroup

CView

DApp

Attempts:

3 left

💡 Hint

Common Mistakes

Using View instead of App

Using Scene instead of App

The main app struct must conform to the App protocol to launch the SwiftUI app.

2fill in blank

medium

Complete the code to create a SwiftUI view named ContentView.

iOS Swift

import SwiftUI

struct ContentView: [1] {
  var body: some View {
    Text("Hello, world!")
  }
}

Drag options to blanks, or click blank then click option'

AView

BWindowGroup

CScene

DApp

Attempts:

3 left

💡 Hint

Common Mistakes

Using App instead of View

Using Scene instead of View

A SwiftUI view must conform to the View protocol to display UI elements.

3fill in blank

hard

Fix the error in the code by completing the missing property wrapper for state management.

iOS Swift

struct CounterView: View {
  [1] var count = 0

  var body: some View {
    VStack {
      Text("Count: \(count)")
      Button("Increment") {
        count += 1
      }
    }
  }
}

Drag options to blanks, or click blank then click option'

A@Binding

B@ObservedObject

C@State

D@EnvironmentObject

Attempts:

3 left

💡 Hint

Common Mistakes

Using @ObservedObject without an observable class

Using @Binding without a source

The @State property wrapper allows the view to update when the variable changes.

4fill in blank

hard

Fill both blanks to create a filter-map chain that filters words longer than 3 characters.

iOS Swift

let words = ["apple", "cat", "dog", "banana"]
let filtered = words.filter { $0.[1] > 3 }.map { $0.[2] }

Drag options to blanks, or click blank then click option'

Acount

Buppercased()

Clowercased()

DisEmpty

Attempts:

3 left

💡 Hint

Common Mistakes

Using isEmpty for length

Using lowercased() when uppercase is needed

Use count to get the length of the word for filtering, and uppercased() to convert the word to uppercase.

5fill in blank

hard

Fill all three blanks to create a SwiftUI view with a button that toggles a boolean state.

iOS Swift

struct ToggleView: View {
  [1] var isOn = false

  var body: some View {
    Button(action: {
      isOn = !isOn
    }) {
      Text(isOn ? [2] : [3])
    }
  }
}

Drag options to blanks, or click blank then click option'

A@State

B"On"

C"Off"

D@Binding

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Binding without a source

Swapping "On" and "Off" texts

@State manages the boolean state. The button text shows "On" when true and "Off" when false.