[Swift5] UISlider tap to change value: Tap on UISlider to Set the Value

you want to know how to change Uislider value on tapping at particular point on the Uislider.

 

 

To change the UISlider value when tapping on a particular point, you can add a tap gesture recognizer to the UISlider and then calculate the value based on the tapped position. Here's how you can achieve this:

 

 

Add a Tap Gesture Recognizer:

First, add a tap gesture recognizer to your UISlider.

let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(sliderTapped(gestureRecognizer:)))
slider.addGestureRecognizer(tapGestureRecognizer)

 

Handle the Tap:

Next, implement the method to handle the tap gesture. In this method, you'll calculate the value based on the tapped position and set it to the slider.

@objc func sliderTapped(gestureRecognizer: UIGestureRecognizer) {
    let pointTapped: CGPoint = gestureRecognizer.location(in: self.view)

    let positionOfSlider: CGPoint = slider.frame.origin
    let widthOfSlider: CGFloat = slider.frame.size.width
    let newValue = ((pointTapped.x - positionOfSlider.x) * CGFloat(slider.maximumValue) / widthOfSlider)

    slider.setValue(Float(newValue), animated: true)
}

 

Complete Example:

Here's a complete example combining the above steps:

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var slider: UISlider!

    override func viewDidLoad() {
        super.viewDidLoad()

        let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(sliderTapped(gestureRecognizer:)))
        slider.addGestureRecognizer(tapGestureRecognizer)
    }

    @objc func sliderTapped(gestureRecognizer: UIGestureRecognizer) {
        let pointTapped: CGPoint = gestureRecognizer.location(in: self.view)

        let positionOfSlider: CGPoint = slider.frame.origin
        let widthOfSlider: CGFloat = slider.frame.size.width
        let newValue = ((pointTapped.x - positionOfSlider.x) * CGFloat(slider.maximumValue) / widthOfSlider)

        slider.setValue(Float(newValue), animated: true)
    }
}

 

It is Swift 5 code

Yes, the code provided is compatible with Swift 5. In Swift 5, the syntax, the way gesture recognizers are added, and the way frames and points are accessed remain the same as in the example provided.

 

With this setup, whenever you tap on the UISlider, it will adjust its value to the tapped position.

 

However, always ensure that you have set up the necessary connections (e.g., the @IBOutlet for the slider) in your Interface Builder if you're using a storyboard or XIB. If you're setting up your UI programmatically, make sure to initialize the UISlider and add it to the view hierarchy before adding the gesture recognizer.

 

Happy Coding!