A subclass of UISlider which has a tool tip indicating the current value of the slider.

CustomSlider.swift

import UIKit

class CustomSlider: UISlider {

    private var toolTip: ToolTipPopupView?
    
    override func awakeFromNib() {
        super.awakeFromNib()
        
        self.initToolTip()
    }
    
    private func initToolTip() {
        toolTip = ToolTipPopupView.init(frame: CGRect.zero)
        toolTip?.backgroundColor = UIColor.clear
        toolTip?.draw(CGRect.zero)
        self.addSubview(toolTip!)
    }
    
    override func thumbRect(forBounds bounds: CGRect, trackRect rect: CGRect, value: Float) -> CGRect {
        
        let knobRect = super.thumbRect(forBounds: bounds, trackRect: rect, value: value)
        
        let popupRect = knobRect.offsetBy(dx: 0, dy: -(knobRect.size.height))
        toolTip?.frame = popupRect.offsetBy(dx: 0, dy: 0)
        toolTip?.setValue(value: self.value)
        
        return knobRect
    }
}

class ToolTipPopupView: UIView {
    
    private var toolTipValue: NSString?
    
    override func draw(_ rect: CGRect) {
        
        if toolTipValue != nil {
            
            let paraStyle = NSMutableParagraphStyle.init()
            paraStyle.lineBreakMode = .byWordWrapping
            paraStyle.alignment = .center
            
            let textAttributes = [NSAttributedStringKey.font: UIFont.textFont(), NSAttributedStringKey.paragraphStyle: paraStyle, NSAttributedStringKey.foregroundColor: UIColor.white]
            
            if let s: CGSize = toolTipValue?.size(withAttributes: textAttributes) {
                let yOffset = s.height
                let textRect = CGRect.init(x: self.bounds.origin.x, y: yOffset, width: self.bounds.size.width, height: s.height)
                

                toolTipValue?.draw(in: textRect, withAttributes: textAttributes)
            }
        }
    }
    
    func setValue(value: Float) {
        toolTipValue = NSString.init(format: "%d", Int(value))
        self.setNeedsDisplay()
    }
}

Thank you. This helped me immensely

You are welcome. I’m glad it did.

I had to change the code to this for it to work. Maybe I have a newer version of swift... although I am coding my first app so idk.

import UIKit

class CustomSlider: UISlider {

    private var tool_tip: ToolTipPopupView?
    
    override func awakeFromNib() {
        super.awakeFromNib()
        
        self.initToolTip()
    }
    
    private func initToolTip() {
        tool_tip = ToolTipPopupView.init(frame: CGRect.zero)
        tool_tip?.backgroundColor = UIColor.clear
        tool_tip?.draw(CGRect.zero)
        self.addSubview(tool_tip!)
    }
    
    override func thumbRect(forBounds bounds: CGRect, trackRect rect: CGRect, value: Float) -> CGRect {
        
        let knobRect = super.thumbRect(forBounds: bounds, trackRect: rect, value: value)
        
        let popupRect = knobRect.offsetBy(dx: 0, dy: -(knobRect.size.height))
        tool_tip?.frame = popupRect.offsetBy(dx: 0, dy: 0)
        tool_tip?.setValue(value: self.value)
        
        return knobRect
    }
}

class ToolTipPopupView: UIView {
    
    private var toolTipValue: NSString?
    
    override func draw(_ rect: CGRect) {
        
        if toolTipValue != nil {
            
            let paraStyle = NSMutableParagraphStyle.init()
            paraStyle.lineBreakMode = .byWordWrapping
            paraStyle.alignment = .center
            
            let textAttributes = [NSAttributedString.Key.font: UIFont(name: "Helvetica", size: 10), NSAttributedString.Key.paragraphStyle: paraStyle, NSAttributedString.Key.foregroundColor: UIColor.white]
            
            if let s: CGSize = toolTipValue?.size(withAttributes: textAttributes as [NSAttributedString.Key : Any]) {
                let yOffset = s.height
                let textRect = CGRect.init(x: self.bounds.origin.x, y: yOffset, width: self.bounds.size.width, height: s.height)
                

                toolTipValue?.draw(in: textRect, withAttributes: textAttributes as [NSAttributedString.Key : Any])
            }
        }
    }
    
    func setValue(value: Float) {
        toolTipValue = NSString.init(format: "%d", Int(value))
        self.setNeedsDisplay()
    }
}

Also what I did not know that you had to:

1. Go to identity inspector while having the slider selected on Main
2. The field with the label class, you need to enter "CustomSlider" (the name of the swift file and class)
3. Tick inherent module from target

Hope this helped any newbies like me. Take what I have done with a grain of salt as I am a newbie.