Creating a new iOS project in iOS Swift - Practice Exercises

Challenge - 5 Problems

❓ ui_behavior

intermediate

What is the initial UI shown when you create a new SwiftUI iOS project?

After creating a new SwiftUI iOS project in Xcode, what does the default ContentView display on the screen?

iOS Swift

import SwiftUI

struct ContentView: View {
    var body: some View {
        Text("Hello, world!")
            .padding()
    }
}

A A screen showing the text "Hello, world!" centered with padding

B A blank white screen with no text

C A screen showing a button labeled "Click me"

D A screen showing an image placeholder

💡 Hint

Think about the default text SwiftUI uses to greet you.

The default ContentView in a new SwiftUI project shows a Text view with "Hello, world!" and some padding around it.

❓ lifecycle

intermediate

What is the role of the @main struct in a new SwiftUI iOS project?

In a new SwiftUI iOS project, what does the struct marked with @main do?

iOS Swift

import SwiftUI

@main
struct MyApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

A It manages the app’s network connections

B It is a placeholder and has no effect

C It defines the app’s background tasks only

D It defines the app’s entry point and main scene for the UI

💡 Hint

This struct tells the system where the app starts running.

The @main attribute marks the app’s entry point. The struct conforming to App defines the main scene and UI window.

📝 Syntax

advanced

What error occurs if you forget to add a body property in the ContentView struct?

Consider this code snippet for ContentView: struct ContentView: View { // body property is missing } What error will Xcode show?

iOS Swift

struct ContentView: View {
    // Missing body property
}

A No errors, compiles fine

B Type 'ContentView' does not conform to protocol 'View'

C Missing return in function

D Unexpected token 'struct'

💡 Hint

The View protocol requires a body property.

The View protocol requires a computed property named body returning some View. Missing it causes a conformance error.

❓ navigation

advanced

How do you add a navigation bar title in a new SwiftUI project?

Given this ContentView, how do you add a navigation bar title "Home"? struct ContentView: View { var body: some View { Text("Welcome") } }

iOS Swift

struct ContentView: View {
    var body: some View {
        NavigationView {
            Text("Welcome")
                .navigationTitle("Home")
        }
    }
}

A Wrap Text in NavigationView and add .navigationTitle("Home") modifier

B Add .title("Home") modifier directly to Text

C Use .navigationBarTitle("Home") on Text without NavigationView

D Set title in App struct instead of ContentView

💡 Hint

Navigation titles require a NavigationView container.

You must wrap your content in NavigationView and then apply .navigationTitle modifier to set the title.

🧠 Conceptual

expert

Why does a new SwiftUI project use WindowGroup in the App struct?

What is the purpose of using WindowGroup in the @main App struct of a new SwiftUI iOS project?

iOS Swift

import SwiftUI

@main
struct MyApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

A It is a legacy container replaced by NavigationView

B It is used to create modal dialogs

C It manages multiple windows and scenes for the app, supporting multitasking

D It only works on macOS and has no effect on iOS

💡 Hint

Think about how iPad apps can have multiple windows.

WindowGroup manages the app’s windows and scenes, enabling multiple windows on iPad and future multitasking features.