How to create a function in which as the +/- buttons increase, the total cost of the product will increase? I wrote this kind of code but it doesn't count right
@IBOutlet weak var counterlbl: UILabel! // Counter label
@IBOutlet var costLbl: UILabel! // Price label
var counter = 1 //Counter which contains the value to increment or decrement(+/-)
let minusTap = UITapGestureRecognizer(target: self, action: #selector(minusImageTapped))
minusBtn.addGestureRecognizer(minusTap)
minusBtn.isUserInteractionEnabled = true
//custom UIstepper I used images
let plusTap = UITapGestureRecognizer(target: self, action: #selector(plusImageTapped))
plusBtn.addGestureRecognizer(plusTap)
plusBtn.isUserInteractionEnabled = true
//decrement
@objc func minusImageTapped () {
let price = costLbl.text
var priceInt = Int(price!)
if counter > 1{
counter -= 1
let totalPrice = priceInt! / counter
counterlbl.text = String(counter)
costLbl.text = String(totalPrice)
print("minus")
}
}
//increment
@objc func plusImageTapped() {
let price = costLbl.text
var priceInt = Int(price!)
counter += 1
let totalPrice = priceInt! * counter
counterlbl.text = String(counter)
costLbl.text = String(totalPrice)
print("Plus")
}
You are changing the cost per item each time...
Let's say you start with counter = 1 and your costLbl has a "5" as its text.
You tap the plus image, and your code does this:
price = costLbl.text // costLbl text is "5"
priceInt = Int(price) // priceInt now equals 5
counter += 1 // counter now equals 2
totalPrice = priceInt * counter // totalPrice now equals 10
you then set costLbl.text = "10"
so, the next time you tap "plus"...
price = costLbl.text // costLbl text is "10" !!!!
priceInt = Int(price) // priceInt now equals 10 !!!!
counter += 1 // counter now equals 3
totalPrice = priceInt * counter // totalPrice now equals 30 !!!!
and you set costLbl.text = "30"
so, the next time you tap "plus"...
price = costLbl.text // costLbl text is "30" !!!!
priceInt = Int(price) // priceInt now equals 30 !!!!
counter += 1 // counter now equals 4
totalPrice = priceInt * counter // totalPrice now equals 120 !!!!
and you set costLbl.text = "120"
and on and on.
You need a CostPerItem label, and a TotalPrice label.
Then, each time through you get the same "Cost per Item" from the CostPerItem label, and display the result of priceInt * counter in the TotalPrice label.
One thing that may have helped you figure this out sooner would be to put your calculations in a single function... then call that function (with an indicator of "incrementing" or "decrementing"), so you aren't confused about the whole multiply or divide issue.
Take a look at this:
class PlusMinusVC: UIViewController {
@IBOutlet var costPerItemLbl: UILabel! // "Cost per Item" label
@IBOutlet var counterLbl: UILabel! // "Number of Items" label
@IBOutlet var totalPriceLbl: UILabel! // Total Price display label
var counter = 1 // Counter (Number of Items) which contains the value to increment or decrement(+/-)
//decrement
@objc func minusImageTapped () {
updateLabels(increment: false)
}
//increment
@objc func plusImageTapped() {
updateLabels(increment: true)
}
func updateLabels(increment: Bool) {
// don't do anything until we make sure we have valid price
// make sure Cost Per Item label has a string
if let priceStr = costPerItemLbl.text {
// make sure we get a valid Int
if let priceInt = Int(priceStr) {
// if we tapped the minus image,
// don't go lower than 1 item
if increment == false {
if counter > 1 {
counter -= 1
} else {
return
}
} else {
counter += 1
}
counterLbl.text = "\(counter)"
let totalPrice = priceInt * counter
totalPriceLbl.text = "Total: \(totalPrice)"
}
}
}
}