uislider value and variable, label association in Swift

Question

I have declared a variable tipPercentage, a UISlider Action tipSliderAction, and a UILabel tipPercentageLabel.
I also created a clear function, so that, when I tap a button, all the above are reset to default values.
Here is the code:

var tipPercentage = 1

@IBOutlet weak var tipPercentageLabel: UILabel!

@IBOutlet weak var tipSlider: UISlider!

@IBAction func tipSliderAction(sender: UISlider) {
    let currentValue = Int(sender.value)
    tipPercentageLabel.text = ("\(currentValue)")
    let percentage = Double(currentValue) / 100
    tipPercentage = percentage
}

@IBAction private func clear(sender: UIButton) {
    tipSlider.value = 10
    tipPercentageLabel.text = String(tipSlider.value)
    tipPercentage = tipSlider.value

clear function is where I reset the values to default. I guess my question is, instead of resetting each individual variables, is there a way to just reset one, then all others will update themselves?
For example, in the clear function, when I just set the tipSlider.value to 10, the tipPercentageLabel.text and tipPercentage will be updated without me setting them in the clear function.
Thank you.

Answer 1

You can do this by adding a handler for ValueChanged event of your UISlider.

override func viewDidLoad()
{
    super.viewDidLoad()
    tipSlider.addTarget(self, action: #selector(ViewController.onValueChanged(_:)), forControlEvents: UIControlEvents.ValueChanged)
}

@IBAction func onValueChanged(sender: AnyObject)
{
  tipPercentageLabel.text = String(tipSlider.value)
  tipPercentage = tipSlider.value
}