UISwitch saving values to use in a function - swift

Question

When the user turns switch on, I would like a random value to display on a UILabel, then take that same random value, and use it to multiply and find another value. I think my problem is that I am trying to use a let statement to hold the value, then trying to call back to that let value from another function, but I don't know another way to to this.
I already can get the random value to appear on a UILabel after the switch is active. Then when the switch is not active, a value of 0 is left on the UILabel.
The IBOutlet for the switch:
#IBOutlet weak var tipSwitch: UISwitch!
This is the action for the switch:
#IBAction func switchChanged(_ sender: UISwitch) {
if sender.isOn{
sender.setOn(false, animated: true)
percentPlaceholder.text! = String(0) + "%"
}
else{
sender.setOn(true, animated: true)
let randomTip = Int.random(in: 1...100)
percentPlaceholder.text! = String(randomTip)
calculateTipSwitch()
}
}
This is the calculateTipSwitch function:
func calculateTipSwitch() {
var tipAmountSwitch = Float()
var totalCostSwitch = Float()
if let billAmountSwitch = Float(billCost.text!) {
tipAmountSwitch = billAmountSwitch * randomTip / 100
totalCostSwitch = tipAmountSwitch + billAmountSwitch
}
else {
tipAmountSwitch = 0
totalCostSwitch = 0
}
tipDollarAmt.text! = String(format: "%.2f", tipAmountSwitch)
totalBill.text! = String(format: "%.2f", totalCostSwitch)
}
Here is all of my code if you want a better understanding of what I'm trying to accomplish:
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var billCost: UITextField!
#IBOutlet weak var percentPlaceholder: UILabel!
#IBOutlet weak var tipDollarAmt: UILabel!
#IBOutlet weak var totalBill: UILabel!
#IBOutlet weak var tipSlider: UISlider!
#IBOutlet weak var tipSegment: UISegmentedControl!
#IBOutlet weak var tipStepper: UIStepper!
#IBOutlet weak var tipSwitch: UISwitch!
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let allowed = CharacterSet(charactersIn: ".1234567890")
return string.rangeOfCharacter(from: allowed) != nil
}
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
billCost.resignFirstResponder()
return true
}
override func viewDidLoad() {
super.viewDidLoad()
percentPlaceholder.text = ""
tipDollarAmt.text = ""
totalBill.text = ""
}
#IBAction func sliderChanged(_ sender: UISlider) {
percentPlaceholder.text! = String(Int(sender.value)) + "%"
tipStepper.value = Double(Int(tipSlider.value))
calculateTip()
}
#IBAction func selectorChanged(_ sender: UISegmentedControl) {
}
#IBAction func stepperChanged(_ sender: UIStepper) {
percentPlaceholder.text! = String(sender.value) + "%"
tipSlider.value = Float(tipStepper.value)
calculateTipStep()
}
#IBAction func switchChanged(_ sender: UISwitch) {
if sender.isOn{
sender.setOn(false, animated: true)
percentPlaceholder.text! = String(0) + "%"
}
else{
sender.setOn(true, animated: true)
let randomTip = Int.random(in: 1...100)
percentPlaceholder.text! = String(randomTip)
}
}
func calculateTip()
{
var tipAmount = Float()
var totalCost = Float()
if let billAmount = Float(billCost.text!) {
tipAmount = billAmount * tipSlider.value / 100
totalCost = tipAmount + billAmount
}
else {
tipAmount = 0
totalCost = 0
}
tipDollarAmt.text! = String(format: "%.2f", tipAmount)
totalBill.text! = String(format: "%.2f", totalCost)
}
func calculateTipStep() {
var tipAmountStep = Float()
var totalCostStep = Float()
if let billAmountStep = Float(billCost.text!) {
tipAmountStep = billAmountStep * Float(tipStepper.value) / 100
totalCostStep = tipAmountStep + billAmountStep
}
else {
tipAmountStep = 0
totalCostStep = 0
}
tipDollarAmt.text! = String(format: "%.2f", tipAmountStep)
totalBill.text! = String(format: "%.2f", totalCostStep)
}
func calculateTipSwitch() {
var tipAmountSwitch = Float()
var totalCostSwitch = Float()
if let billAmountSwitch = Float(billCost.text!) {
tipAmountSwitch = billAmountSwitch * randomTip / 100
totalCostSwitch = tipAmountSwitch + billAmountSwitch
}
else {
tipAmountSwitch = 0
totalCostSwitch = 0
}
tipDollarAmt.text! = String(format: "%.2f", tipAmountSwitch)
totalBill.text! = String(format: "%.2f", totalCostSwitch)
}
}
Basically my problem is that I can't use that random number in another function, so I just need help on how to call back to that randomTip.

Answer 1

You can add a parameter to calculateTipSwitch, and pass the random number as an argument to the calculateTipSwitch method. Change calculateTipSwitch to:
func calculateTipSwitch(tipPercentage: Int) {
var tipAmountSwitch = Float()
var totalCostSwitch = Float()
if let billAmountSwitch = Float(billCost.text!) {
tipAmountSwitch = billAmountSwitch * tipPercentage / 100.0
totalCostSwitch = tipAmountSwitch + billAmountSwitch
}
else {
tipAmountSwitch = 0
totalCostSwitch = 0
}
tipDollarAmt.text! = String(format: "%.2f", tipAmountSwitch)
totalBill.text! = String(format: "%.2f", totalCostSwitch)
}
Then, in switchChanged:
let randomTip = Int.random(in: 1...100)
percentPlaceholder.text! = String(randomTip)
calculateTipSwitch(tipPercentage: randomTip)

Answer 2

In the switchChanged() function , you set the randomTip to percentPlaceholder.text , so in the other functions , you could just call for it.
let randomTip = percentPlaceholder.text
Or another way to do this, is to declare the randomTip variable outside the function, as a property of the class.
class ViewController : UIViewController {
//IBOutlets here
var randomTip : String?
//functions here
}
Then when you set a value to it in switchChanged(), it can be called in the other functions.