UIStepper

UIStepper is a UIControl subclass in UIKit that provides a user interface for incrementing or decrementing a numeric value. It features two buttons (plus and minus) for adjusting the value and is commonly used in iOS apps for tasks like selecting quantities, adjusting settings, or setting numerical preferences.

Properties

Property	Type	Description	Default Value
value	Double	The current numeric value of the stepper.	0.0
minimumValue	Double	The lowest possible value.	0.0
maximumValue	Double	The highest possible value.	100.0
stepValue	Double	The increment/decrement amount per tap.	1.0
isContinuous	Bool	If true, sends continuous updates while a button is held.	true
autorepeat	true	If true, holding a button continuously increments/decrements the value.	Always true
wraps	Bool	If true, the value wraps around when it exceeds the minimum/maximum.	false
tintColor	UIColor?	The color of the stepper’s buttons and icons.	System-defined

Methods

Method	Return Type	Description
setIncrementImage(_:for:)	Void	Sets a custom image for the increment button for a given control state (e.g., .normal, .disabled).
setDecrementImage(_:for:)	Void	Sets a custom image for the decrement button for a given control state.
setBackgroundImage(_:for:)	Void	Sets a background image for the stepper for a given control state.
setDividerImage(_:forLeftSegmentState:rightSegmentState:)	Void	Sets the divider image between the buttons for specified states.
addTarget(_:action:for:)	Void	Associates a target and action for control events (e.g., .valueChanged).
incrementImage(for:)	UIImage?	Returns the image used for the increment button for a given state.
decrementImage(for:)	UIImage?	Returns the image used for the decrement button for a given state.
backgroundImage(forLeftSegmentState:rightSegmentState:)	UIImage?	Returns the divider image for specified segment states.

Example Usage

Example 1: Basic Stepper with Label

This example creates a stepper to adjust a quantity and updates a label with the current value.

import UIKit

class ViewController: UIViewController {
    let stepper = UIStepper()
    let label = UILabel()

    override func viewDidLoad() {
        super.viewDidLoad()
        
        // Configure stepper
        stepper.frame = CGRect(x: 100, y: 200, width: 0, height: 0)
        stepper.minimumValue = 1
        stepper.maximumValue = 10
        stepper.stepValue = 1
        stepper.value = 1
        stepper.addTarget(self, action: #selector(stepperValueChanged(_:)), for: .valueChanged)
        
        // Configure label
        label.frame = CGRect(x: 100, y: 150, width: 200, height: 30)
        label.textAlignment = .center
        label.text = "Quantity: \(Int(stepper.value))"
        
        // Add to view
        view.addSubview(stepper)
        view.addSubview(label)
    }

    @objc func stepperValueChanged(_ sender: UIStepper) {
        label.text = "Quantity: \(Int(sender.value))"
    }
}

Example 2: Custom Stepper with Images and Wrapping

This example customizes the stepper’s appearance with images and enables value wrapping.

import UIKit

class CustomViewController: UIViewController {
    let stepper = UIStepper()
    let valueLabel = UILabel()

    override func viewDidLoad() {
        super.viewDidLoad()
        
        // Configure stepper
        stepper.frame = CGRect(x: 100, y: 300, width: 0, height: 0)
        stepper.minimumValue = 0
        stepper.maximumValue = 5
        stepper.stepValue = 0.5
        stepper.wraps = true
        stepper.tintColor = .systemBlue
        stepper.setIncrementImage(UIImage(systemName: "plus.circle"), for: .normal)
        stepper.setDecrementImage(UIImage(systemName: "minus.circle"), for: .normal)
        stepper.addTarget(self, action: #selector(updateLabel(_:)), for: .valueChanged)
        
        // Configure label
        valueLabel.frame = CGRect(x: 100, y: 250, width: 200, height: 30)
        valueLabel.textAlignment = .center
        valueLabel.text = "Value: \(stepper.value)"
        
        // Add to view
        view.addSubview(stepper)
        view.addSubview(valueLabel)
    }

    @objc func updateLabel(_ sender: UIStepper) {
        valueLabel.text = "Value: \(sender.value)"
    }
}

Example 3: Stepper with Continuous Updates

This example demonstrates a stepper with continuous updates and a non-integer step value.

import UIKit

class ContinuousViewController: UIViewController {
    let stepper = UIStepper()
    let progressLabel = UILabel()

    override func viewDidLoad() {
        super.viewDidLoad()
        
        // Configure stepper
        stepper.frame = CGRect(x: 100, y: 400, width: 0, height: 0)
        stepper.minimumValue = 0
        stepper.maximumValue = 1
        stepper.stepValue = 0.1
        stepper.isContinuous = true
        stepper.addTarget(self, action: #selector(progressChanged(_:)), for: .valueChanged)
        
        // Configure label
        progressLabel.frame = CGRect(x: 100, y: 350, width: 200, height: 30)
        progressLabel.textAlignment = .center
        progressLabel.text = "Progress: \(Int(stepper.value * 100))%"
        
        // Add to view
        view.addSubview(stepper)
        view.addSubview(progressLabel)
    }

    @objc func progressChanged(_ sender: UIStepper) {
        progressLabel.text = "Progress: \(Int(sender.value * 100))%"
    }
}

Customization

• Tint Color: Modify tintColor to change the stepper’s button color (e.g., stepper.tintColor = .systemRed).
• Custom Images: Use setIncrementImage(_:for:) and setDecrementImage(_:for:) for custom button icons.
• Background: Set a background image with setBackgroundImage(_:for:).
• Divider: Customize the divider with setDividerImage(_:forLeftSegmentState:rightSegmentState:).

Accessibility

• Set accessibilityLabel (e.g., "Adjust Quantity").
• Update accessibilityValue dynamically (e.g., "(Int(stepper.value)) items").
• Ensure isAccessibilityElement is true for VoiceOver support.

Notes

• Available since iOS 5.0.
• Use .valueChanged event to handle value updates.
• The stepper’s size is fixed; position it using Auto Layout or frames.
• For SwiftUI, use the Stepper view for a declarative alternative.

Resources

• Apple Documentation: UIStepper
• UIKit Framework Reference