Pass Data using a pushViewController? - ios

Question

Using this code I am able to 'segue' to the same instance of my view controller
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: "DetailVC")
self.navigationController?.pushViewController(vc, animated: true)
}
However, how do I pass data over? I only know how to pass data using the segue option. When I run the code with this, I get nil errors because the new instantiated view controller cannot read the data.

Answer 1

for example I add here, for detail description you can get the tutorial from here
class SecondViewController: UIViewController {
var myStringValue:String?
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
// We will simply print out the value here
print("The value of myStringValue is: \(myStringValue!)")
}
and send the string as
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: "DetailVC") as! SecondViewController
vc.myStringValue = "yourvalue"
self.navigationController?.pushViewController(vc, animated: true)
}

Answer 2

First off. This isn't a segue. This is just pushing another view to the stack. And (like Ashley Mills says) this is not the same instance you are currently in. This is a NEW instance of a view controller.
But all you need to do is populate the data. You already have the controller here...
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
// you need to cast this next line to the type of VC.
let vc = storyboard.instantiateViewController(withIdentifier: "DetailVC") as! DetailVC // or whatever it is
// vc is the controller. Just put the properties in it.
vc.thePropertyYouWantToSet = theValue
self.navigationController?.pushViewController(vc, animated: true)
}
Then in your second view controller catch the value like this
class DetailVC: UIViewController {
var thePropertyYouWantToSet = String()
override func viewDidLoad() {
print(thePropertyYouWantToSet)
}
}

Answer 3

What you're using isn't a segue. This is just pushing a NEW instance (not the same one) of view controller onto the nav stack.
To segue, in your storyboard, you can just drag a link from the collection view cell to the view controller, then assign data in the prepareForSegue method…
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if let viewController = segue.destinationViewController as? DetailVC {
viewController.someProperty = self.someProperty
}
}

Answer 4

In DetailVC, Create a variable and assign value while you create an object. Check example below:
class DetailVC {
var dataString: String?
}
Pass data like below:
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: "DetailVC") as! DetailVC
vc.dataString = "PASS THE DATA LIKE THIS"
self.navigationController?.pushViewController(vc, animated: true)
}

Answer 5

If you're following the no storyboard pattern you can do it like this
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let viewController = NextViewController()
viewController.dataInsideNextViewController = "Data to be passed"
navigationController?.pushViewController(viewController, animated: true)
}

Answer 6

In your ViewController1 launch your ViewController2 using these code
Class ViewController1: UIViewController {
var dataFromVC2 = ""
func loadVC2() {
let vc2 = ViewController2()
vc2.dataFromVC1 = "Hi VC2"
vc2delegate = self
navigationController?.pushViewController(vc2, animated: true)
}
}
In your ViewController2, add this code. You can use the delegate property to pass back data from ViewContoller2.
Class ViewController2: UIViewController {
var dataFromVC1: String = ""
weak var delegate: ViewController1!
func passData_toVC1() {
delegate.dataFromVC2 = "How's it going VC1?"
}
}