Image view (system and asset) in iOS Swift

Introduction

Images make apps look nice and help users understand content quickly. Using image views lets you show pictures from your app or the system easily.

Showing a logo or icon from your app's files.

Displaying a photo or picture stored inside your app.

Using built-in system icons like a trash bin or heart.

Adding decorative images to buttons or backgrounds.

Syntax

iOS Swift

let imageView = UIImageView(image: UIImage(named: "imageName"))

// For system image
let systemImageView = UIImageView(image: UIImage(systemName: "star.fill"))

Use UIImage(named:) to load images you added to your app's assets.

Use UIImage(systemName:) to load Apple's built-in icons.

Examples

This creates an image view showing your app's "logo" image from assets.

iOS Swift

let logoImageView = UIImageView(image: UIImage(named: "logo"))

This creates an image view showing a filled heart icon from the system.

iOS Swift

let heartImageView = UIImageView(image: UIImage(systemName: "heart.fill"))

Sample App

This app screen shows two images side by side: one from your app's assets named "exampleImage" and one system star icon colored yellow.

iOS Swift

import UIKit

class ViewController: UIViewController {
  override func viewDidLoad() {
    super.viewDidLoad()
    
    view.backgroundColor = .white
    
    // Image from app assets
    let assetImageView = UIImageView(image: UIImage(named: "exampleImage"))
    assetImageView.frame = CGRect(x: 50, y: 100, width: 100, height: 100)
    assetImageView.contentMode = .scaleAspectFit
    view.addSubview(assetImageView)
    
    // System image
    let systemImageView = UIImageView(image: UIImage(systemName: "star.fill"))
    systemImageView.frame = CGRect(x: 200, y: 100, width: 100, height: 100)
    systemImageView.tintColor = .systemYellow
    systemImageView.contentMode = .scaleAspectFit
    view.addSubview(systemImageView)
  }
}

Important Notes

Make sure your asset image name matches exactly, including capitalization.

System images can be tinted by changing the tintColor property.

Set contentMode to control how the image fits inside the image view.

Summary

Use UIImageView to display images in your app.

Load images from your assets with UIImage(named:).

Use Apple's system icons with UIImage(systemName:) and customize their color.

Practice

1. What is the correct way to create an image view that displays an image named "logo" from your app's assets?

easy

A. UIImageView(image: UIImage(named: "logo"))

B. UIImageView(image: UIImage(systemName: "logo"))

C. UIImageView(named: "logo")

D. UIImageView(systemName: "logo")

Solution

1. Step 1: Understand UIImageView initialization

   UIImageView is initialized with a UIImage object, not a string name directly.

2. Step 2: Load image from assets correctly

   Use UIImage(named:) to load an image from app assets by name.

3. Final Answer:

   UIImageView(image: UIImage(named: "logo")) -> Option A

4. Quick Check:

   Load asset image with UIImage(named:) = D [OK]

Hint: Use UIImage(named:) for asset images, not systemName [OK]

Common Mistakes:

• Using UIImage(systemName:) for asset images
• Passing string directly to UIImageView initializer
• Confusing UIImageView(named:) which doesn't exist

2. Which of the following is the correct syntax to create a system image view with the icon named "star.fill"?

easy

A. UIImageView(image: UIImage(named: "star.fill"))

B. UIImageView(systemName: "star.fill")

C. UIImageView(image: UIImage(systemName: "star.fill"))

D. UIImageView(image: "star.fill")

Solution

1. Step 1: Identify system image loading method

   System icons are loaded using UIImage(systemName:).

2. Step 2: Initialize UIImageView with system image

   Pass UIImage(systemName: "star.fill") to UIImageView's image parameter.

3. Final Answer:

   UIImageView(image: UIImage(systemName: "star.fill")) -> Option C

4. Quick Check:

   System image uses UIImage(systemName:) = B [OK]

Hint: Use UIImage(systemName:) for system icons only [OK]

Common Mistakes:

• Using UIImage(named:) for system icons
• Trying to initialize UIImageView with systemName directly
• Passing string instead of UIImage object

3. What will be the result of this Swift code snippet?

let imageView = UIImageView(image: UIImage(systemName: "heart.fill"))
imageView.tintColor = .red

medium

A. An image view showing a red filled heart system icon

B. An image view showing a heart icon with default color (black)

C. A runtime error because tintColor cannot be set

D. An empty image view with no image displayed

Solution

1. Step 1: Load system image "heart.fill"

   UIImage(systemName: "heart.fill") loads a filled heart icon.

2. Step 2: Set tintColor to red

   Setting imageView.tintColor to .red colors the system icon red.

3. Final Answer:

   An image view showing a red filled heart system icon -> Option A

4. Quick Check:

   System icon + tintColor = colored icon [OK]

Hint: System icons respect tintColor for color changes [OK]

Common Mistakes:

• Assuming system icons ignore tintColor
• Confusing asset images with system icons for tinting
• Expecting default black color after setting tintColor

4. Identify the error in this Swift code that tries to display a system image "bell" in an image view:

let imageView = UIImageView(image: UIImage(named: "bell"))
imageView.tintColor = .blue

medium

A. The code is correct and will display a blue bell icon

B. UIImageView does not have a tintColor property

C. The image name "bell" is invalid for assets

D. UIImage(named:) cannot load system images like "bell"

Solution

1. Step 1: Check image loading method

   UIImage(named:) loads images from app assets, not system icons.

2. Step 2: Recognize system image loading requirement

   System images like "bell" must be loaded with UIImage(systemName:).

3. Final Answer:

   UIImage(named:) cannot load system images like "bell" -> Option D

4. Quick Check:

   System images need UIImage(systemName:) = A [OK]

Hint: Use UIImage(systemName:) for system icons, not UIImage(named:) [OK]

Common Mistakes:

• Using UIImage(named:) for system icons
• Assuming tintColor works without correct image loading
• Thinking UIImageView lacks tintColor property

5. You want to display a system image "trash" in red color and an asset image "icon" in your app. Which code snippet correctly creates both UIImageViews with the right images and colors?

hard

A. let trashView = UIImageView(image: UIImage(systemName: "trash"))
trashView.tintColor = .red
let iconView = UIImageView(image: UIImage(systemName: "icon"))

B. let trashView = UIImageView(image: UIImage(systemName: "trash"))
trashView.tintColor = .red
let iconView = UIImageView(image: UIImage(named: "icon"))

C. let trashView = UIImageView(image: UIImage(named: "trash"))
trashView.tintColor = .red
let iconView = UIImageView(image: UIImage(systemName: "icon"))

D. let trashView = UIImageView(image: UIImage(named: "trash"))
trashView.tintColor = .red
let iconView = UIImageView(image: UIImage(named: "icon"))

Solution

1. Step 1: Load system image "trash" correctly

   Use UIImage(systemName: "trash") for system icon and set tintColor to red.

2. Step 2: Load asset image "icon" correctly

   Use UIImage(named: "icon") for asset image without tintColor.

3. Final Answer:

   let trashView = UIImageView(image: UIImage(systemName: "trash"))\ntrashView.tintColor = .red\nlet iconView = UIImageView(image: UIImage(named: "icon")) -> Option B

4. Quick Check:

   System image + tintColor, asset image with UIImage(named:) = C [OK]

Hint: System images use systemName + tintColor; assets use named without tint [OK]

Common Mistakes:

• Mixing UIImage(named:) and UIImage(systemName:) incorrectly
• Setting tintColor on asset images expecting color change
• Using systemName for asset images