Image view (system and asset) in iOS Swift - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ ui_behavior

intermediate

Displaying a system image in SwiftUI

What will be displayed by this SwiftUI code snippet?

iOS Swift

import SwiftUI

struct ContentView: View {
  var body: some View {
    Image(systemName: "star.fill")
      .foregroundColor(.yellow)
      .font(.largeTitle)
  }
}

A A large yellow filled star icon

B A large gray filled star icon

C A large yellow outlined star icon

D A large gray outlined star icon

💡 Hint

The systemName parameter uses SF Symbols, and foregroundColor changes the icon color.

The code uses Image(systemName:) to show the SF Symbol "star.fill" which is a filled star. The foregroundColor(.yellow) changes the star's color to yellow, and font(.largeTitle) makes it large.

❓ ui_behavior

intermediate

Displaying an asset image in UIKit

What will this UIKit code display on the screen?

iOS Swift

import UIKit

class ViewController: UIViewController {
  override func viewDidLoad() {
    super.viewDidLoad()
    let imageView = UIImageView(image: UIImage(named: "logo"))
    imageView.frame = CGRect(x: 50, y: 50, width: 100, height: 100)
    view.addSubview(imageView)
  }
}

A A system image named "logo" shown at position (50,50)

B A blank view because "logo" image is not loaded

C An image named "logo" from the app assets shown at position (50,50) with size 100x100

D An error because UIImage(named:) cannot be used in viewDidLoad

💡 Hint

UIImage(named:) loads images from the app's asset catalog by name.

UIImage(named: "logo") loads the image named "logo" from the app's assets. UIImageView displays it at the specified frame. This code shows the image at (50,50) with width and height 100.

📝 Syntax

advanced

Correct syntax for system image with rendering mode

Which option correctly creates a SwiftUI Image with system name "heart" and applies original rendering mode?

A Image(systemName: "heart").renderingMode(.original)

B Image(systemName: "heart").renderingMode(.template)

C Image(systemName: "heart", renderingMode: .original)

D Image(systemName: "heart").renderMode(.original)

💡 Hint

Rendering mode is a modifier method in SwiftUI, not a parameter in initializer.

In SwiftUI, renderingMode is a modifier method called on the Image view. Option A uses the correct syntax. Option A tries to pass renderingMode as a parameter which is invalid. Option A uses .template which is different mode. Option A uses wrong method name.

🔧 Debug

advanced

Why does UIImage(named:) return nil?

Given this UIKit code, why might imageView.image be nil? let imageView = UIImageView() imageView.image = UIImage(named: "icon")

A UIImageView cannot display images loaded with UIImage(named:)

B The image named "icon" is missing from the asset catalog or bundle

C UIImage(named:) requires a full file path, not just the name

D imageView.image must be set inside viewDidLoad to work

💡 Hint

UIImage(named:) returns nil if the image name is not found in assets or bundle.

UIImage(named:) looks for the image in the app's asset catalog or bundle by name. If the image is missing or the name is misspelled, it returns nil. UIImageView can display images loaded this way. The method does not require full path. Setting image outside viewDidLoad is allowed.

🧠 Conceptual

expert

Difference between system and asset images in iOS

Which statement correctly describes the difference between system images and asset images in iOS development?

A System images are always raster images, asset images are always vector images

B System images must be added manually to assets, asset images are built-in icons from Apple

C System images can only be used in UIKit, asset images only in SwiftUI

D System images are vector icons provided by Apple (SF Symbols), asset images are custom images added to the app bundle

💡 Hint

Think about where system images come from and how asset images are added.

System images are vector icons called SF Symbols provided by Apple and can be used by name. Asset images are custom images developers add to the app's asset catalog or bundle. System images are vector and scalable, asset images can be raster or vector. Both UIKit and SwiftUI can use both types.