passing data between view controllers without changing views - ios

Question

I want to pass data between two view controllers, but don't want the view to change when the users presses my save data button.
The users needs to fill in multiple data fields, and when finish can press another button to go to the second view controller.
I found many tutorials how to pass data using segue, but they all change view as soon as the 'save button is pressed'.
Any one can explain to me how to alter the code?
#Phillip Mills: here is how I used your code. (what am I doing wrong?)
code:
//////// declaring classes on FirstViewController (trying it first on only one ViewController)
class FakeVC1 {
func userInput() {
DataModel.shared.username = outbj14u.text
}
class FakeVC2 {
func viewAppears() {
if let name = DataModel.shared.username {
outbj14p.text = name
print("I have nothing to say")
}
}
}
class DataModel {
static let shared = DataModel()
var username: String?
}
////till here
//// here is where i call the functions
override func viewDidAppear(_ animated: Bool) {
FakeVC1().userInput()
FakeVC2().viewAppears()
if let xbj14p = UserDefaults.standard.object(forKey: "outbj14p") as? String
{
outbj14p.text = xbj14p
}
if let xbj14u = UserDefaults.standard.object(forKey: "outbj14u") as? String
{
outbj14u.text = xbj14u
}
////
#Phillip Mills: Below is what I have know. I think I got the code on the FirstViewController right, but the code on the Second View controller must be wrong. I don't get any errors, but the text field on the SecondViewController remains unchanged after putting input on in the FirstViewController
//// Code on the FirstViewController
class DataModel {
static let shared = DataModel()
var username: String?
}
#IBAction func savebj14p(_ sender: Any) {
outbj14p.text = inbj14p.text
DataModel.shared.username = outbj14p.text
UserDefaults.standard.set(inbj14p.text, forKey: "namebj14p")
}
//and on the SecondViewController
#IBOutlet weak var bj14u: UILabel! // connected to a label
//and
class DataModel {
static let shared = DataModel()
var username: String?
}
override func viewDidAppear(_ animated: Bool) {
if let name = DataModel.shared.username {
bj14u.text = name
}
}

Answer 1

In your case, don't pass data.
Create a shared object to act as your data model. When users fill in the fields, update the data model.
When the user moves to the second controller/view, that controller uses the data model object to show what it needs to.
class FakeVC1 {
func userInput() {
DataModel.shared.username = "Me"
}
}
class FakeVC2 {
func viewAppears() {
if let name = DataModel.shared.username {
print(name)
} else {
print("I have nothing to say")
}
}
}
class DataModel {
static let shared = DataModel()
var username: String?
}
FakeVC1().userInput()
FakeVC2().viewAppears()

Answer 2

If you need to pass value to another viewcontroller without changing the view , you can user NSNotificationCenter class
Refer this link for more details
NSNotificationCenter addObserver in Swift

Answer 3

what i will recommend is to use a global variable or array, you will have the info in all view controllers and you will be able to call it in your new view controller.