Swift: Calling Functions from different View Controllers - ios

Question

Im very new to swift, I have a tabbed page app with 5 different view controllers and 5 different view controller.swift files.Each view controller has similar Syntax but a few names and labels are different. Each controller has a function that will restart my data values and they all work per page. but what I am trying to do, is access the clear functions from each view controller by just pressing one button from one view controller. My formatting/logic may be completely off. Im teaching myself so any help is appreciated
import UIKit
class FirstViewController: UIViewController {
// North wing
var nTotal = 0
var total = 0
//Stepper Values
#IBOutlet weak var tStepper: UIStepper!
#IBOutlet weak var cStepper: UIStepper!
#IBOutlet weak var ssStepper: UIStepper!
#IBOutlet weak var sStepper: UIStepper!
//-Tables
#IBOutlet weak var Tables: UILabel!
#IBAction func TCounter(_ sender: UIStepper) {
Tables.text = String(Int(sender.value))
}
//-Carrels
#IBOutlet weak var Carrels: UILabel!
#IBAction func CCounter(_ sender: UIStepper) {
Carrels.text = String(Int(sender.value))
}
//-Soft Seating
#IBOutlet weak var SoftSeating: UILabel!
#IBAction func SSCounter(_ sender: UIStepper) {
SoftSeating.text = String(Int(sender.value))
}
//-Standing
#IBOutlet weak var Standing: UILabel!
#IBAction func SCounter(_ sender: UIStepper) {
Standing.text = String(Int(sender.value))
}
//-Clear Pop-up
#IBAction func Clear(_ sender: UIButton) {
let alert = UIAlertController(title: "Clear", message: "Clear all or current page?", preferredStyle: .alert)
let clearPage = UIAlertAction(title: "Clear Page", style: .default, handler: {ACTION in
self.nClear()
})
let clearAll = UIAlertAction(title: "Clear All", style: .destructive, handler: {ACTION in
self.MasterClear()
})
let Cancel = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)
alert.addAction(clearPage)
alert.addAction(clearAll)
alert.addAction(Cancel)
self.present(alert, animated: true, completion: nil)
}
This is the clear function on all of my view controllers
//Clear Function
func nClear() {
self.Tables.text = "0"
self.Carrels.text = "0"
self.SoftSeating.text = "0"
self.Standing.text = "0"
//Stepper Clear
self.tStepper.value = 0
self.cStepper.value = 0
self.ssStepper.value = 0
self.sStepper.value = 0
}
This is the function that I want to be able to access all the clear functions I have on every Controller
//Clear all Function
func MasterClear(){
self.nClear()
SecondViewController().iLClear()
}
my code breaks and app crashes when I run and access the master clear function

Answer 1

What you really want to do is make a model of the data you want to share between the different views one for each of your views. I will do a sample with one. create a swift file for your data model like this:
class TestModel {
var Tables: String = "0"
var Carrels: String = "0"
var SoftSeating: String = "0"
var Standing: String = "0"
//Stepper Clear
var tStepper: Int = 0
var cStepper: Int = 0
var ssStepper: Int = 0
func modelReset() {
Tables = "0"
Carrels = "0"
SoftSeating = "0"
Standing = "0"
tStepper = 0
cStepper = 0
ssStepper = 0
}
}
next in your first view controller add a variable that is an instance of the model
class FirstViewController: UIViewController {
var modelController: TestModel!
and in your viewDidLoad function initialize the variable
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
modelController = TestModel()
}
create your clear function. I called mine reset:
#IBAction func reset(_ sender: Any) {
//Do for each ViewConrtoller
modelController.modelReset()
}
now override the prepare function to send the data to the view controller we are going to
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let secondViewController = segue.destination as? SecondViewController {
secondViewController.modelController = modelController
}
}
now in your second view controller create a variable of the model but in this instance we will not initialize it in the viewDidLoad function.
class SecondViewController: UIViewController {
var modelController: TestModel!
we don't initialize it as we are passing it from the first view controller in our prepare function.
in the second view controllers viewWillApear function update the view with the data from the model
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
self.Tables.text = modelController.Tables
self.Carrels.text = modelController.Carrels
self.SoftSeating.text = modelController.SoftSeating
self.Standing.text = modelController.Standing
//Stepper Clear
self.tStepper.value = modelController.tStepper
self.cStepper.value = modelController.cStepper
self.ssStepper.value = modelConroller.ssStepper
}
one last step don't forget to implement the prepare function to pass the model back to the first view controller in case you have updated it
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let secondViewController = segue.destination as? SecondViewController {
secondViewController.modelController = modelController
}
}