Passing the UISlider value to the previous page [closed] - ios

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I'm making a Pomodoro app and adjusting the focus time using UISlider.I can access the UISlider value on the screen where I define the UISlider. But I want to switch to the previous screen. I failed. My first page is ViewController(), my second page is SettingsVC().
It's my 5th month in software.
Very happy if you help.
Firs Page
import UIKit
class ViewController: UIViewController {
let actionButton = SFActionButton()
var minutesLabel = SFTimeLabel(text: "25")
let secondsLabel = SFTimeLabel(text: "00")
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .systemBackground
}
#objc func controll(){
print("Slider Value : \(SettingsVC().focusTimeSlider.value)")
print("Working")
}
#objc func settingsAction(){
let rootVC = SettingsVC()
let navVC = UINavigationController(rootViewController: rootVC)
navVC.modalPresentationStyle = .fullScreen
self.present(navVC, animated: true, completion: nil)
}
}
This code page is my first page.
Second Page
import UIKit
class SettingsVC: UIViewController {
//MARK: - Sliders
var focusTimeSlider = UISlider()
let shortBreakTimeSlider = UISlider()
let longBreakTimeSlider = UISlider()
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .systemBackground
title = "Settings"
}
//MARK: - Done Button
func addCloseButton(){
let button = UIBarButtonItem(title: "Done", style: .done, target: self, action: #selector(onClose))
navigationItem.rightBarButtonItem = button
}
#objc func onClose(){
self.dismiss(animated: true, completion: nil)
print("Focus Time : \(Int(focusTimeSlider.value))")
print("Short Break Time : \(Int(shortBreakTimeSlider.value))")
print("Long Break Time : \(Int(longBreakTimeSlider.value))")
}
//MARK: - Slider Actions
func layoutFocusTimeSlider(){
focusTimeSlider.addTarget(self, action: #selector(focusSliderValueChanged(sender:)), for: .valueChanged)
}
#objc func focusSliderValueChanged(sender: UISlider){
focusTimeSliderValueLabel.text = String(Int(focusTimeSlider.value))
}
func layoutShortBreakTimeSlider(){
shortBreakTimeSlider.addTarget(self, action: #selector(shortSliderValueChanged), for: .valueChanged)
}
#objc func shortSliderValueChanged(){
shortBreakTimeSliderValueLabel.text = String(Int(shortBreakTimeSlider.value))
}
func layoutLongBreakTimeSlider(){
longBreakTimeSlider.addTarget(self, action: #selector(longSliderValueChanged), for: .valueChanged)
}
#objc func longSliderValueChanged(){
longBreakTimeSliderValueLabel.text = String(Int(longBreakTimeSlider.value))
}
}
This code page is my second page.

Answer 1

I have two solutions
First solution:
You can add a new function in the first ViewController
func sliderValue(value: CGFloat) {
// add what you want to do here with the value
}
then you add variable in the settings view will hold the parentView instance
like this
weak var parentView: UIViewController?
and when you presenting the settings view controller you assign the parent view controller to the parentView instance before presenting
#objc func settingsAction(){
let rootVC = SettingsVC()
rootVC.parentView = self
let navVC = UINavigationController(rootViewController: rootVC)
navVC.modalPresentationStyle = .fullScreen
self.present(navVC, animated: true, completion: nil)
}
then before dismissing the settings view you call the function sliderValue
#objc func onClose(){
if let parentView = parentView as? ViewController {
parentView.sliderValue(value: focusTimeSlider.value)
}
self.dismiss(animated: true, completion: nil)
print("Focus Time : \(Int(focusTimeSlider.value))")
print("Short Break Time : \(Int(shortBreakTimeSlider.value))")
print("Long Break Time : \(Int(longBreakTimeSlider.value))")
}
Second Solution:
You will add the sliderValue(value:) function but you will not create the parentView variable instead you will do as follow
#objc func onClose(){
if let viewController = presentingViewController as? ViewController {
viewController.sliderValue(value: focusTimeSlider.value)
}
self.dismiss(animated: true, completion: nil)
print("Focus Time : \(Int(focusTimeSlider.value))")
print("Short Break Time : \(Int(shortBreakTimeSlider.value))")
print("Long Break Time : \(Int(longBreakTimeSlider.value))")
}
self.presentingViewController this variable holds the presenting view controller which in this case will hold the value for the ViewController then you will need to downcast it to be able to access the sliderValue function . you can find more about this property in the apple documentation presentingViewController