Parse with Swift - Unresolved Identifiier - ios

Question

I'm new to Swift and Xcode in general. I'm trying to make an app similar in essence to Twitter. My issue is that after my Table View Controller for my timeline I have two pages/View Controllers: one with a picker to choose a specific house and the next to make a text post.
On the Second View Controller's code with the text, I try to save an object with the post's content and the selected house to Parse. The content is saved just fine. But I get errors when I try to do the same to the house (because it's from a different page)
I'm positive this is a very simple, obvious thing I am missing....
Thanks!
Edit: I'm doing anonymous users btw if that's relevant
code for the picker from the first view controller
#IBOutlet weak var label: UILabel!
#IBOutlet weak var picker: UIPickerView!
let pickerData = ["Adams","Cabot","Currier","Dunster","Eliot","Kirkland","Leverett","Lowell","Mather","Pforzheimer","Quincy","Winthrop"]
func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(pickerView: UIPickerView,
numberOfRowsInComponent component: Int) -> Int {
return pickerData.count
}
func pickerView(pickerView: UIPickerView,
titleForRow row: Int,
forComponent component: Int) -> String!{
return pickerData[row]
}
func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int){
self.label.text = pickerData[row]
}
override func viewDidLoad() {
super.viewDidLoad()
// label is "Adams" when first loaded
label.text = pickerData[0]
picker = UIPickerView()
}
code to from the second view control to Save it to Parse
#IBAction func PostText(sender: AnyObject) {
// establish object to save in Parse CHANGE USER TO HOUSE
var post:PFObject = PFObject(className: "Posts")
post["content"] = PostTextView.text
post["user"] = PFUser.currentUser()
post["house"] = pickerData[row].text
post.saveInBackgroundWithTarget(nil , selector: nil)
// return to navigation screen
self.navigationController?.popToRootViewControllerAnimated(true)
}
error is unresolved identifier (because they're defined in another view controller?)

Answer 1

Neither pickerData nor row belong to Second View Controller (i.e. they're unresolved identifiers) so you have to get an instance of First View Controller to access the pickerData variable and to find picker's currently selected "row."
As long as you're using a UINavigationController you can find any previous view controller in the stack. If FirstViewController is immediately preceding the current SecondViewController, you can find it one index behind on the navigation stack, ex:
let navigationController: UINavigationController = self.navigationController!
let numberOfViewControllers = navigationController.viewControllers.count
var firstViewController: FirstViewController = navigationController.viewControllers[numberOfViewControllers - 2] as FirstViewController
let row = firstViewController.picker.selectedRowInComponent(0)
post["house"] = firstViewController.pickerData[row]
But generally speaking, it's probably cleaner to send your view controller object forward instead of pulling it from the nav stack.
If you're using a Storyboard, for example, you can update the prepareToSegue method in your first view controller to share your current FirstViewController instance with your second view controller:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
// (Uncomment the if block and specify a segue if this isn't the
// segue leading from your view controller.)
//if segue.identifier == "yourSegueName" {
let secondViewController = segue.destinationViewController as SecondViewController
secondViewController.firstViewController = self;
//}
}
Then in your second view controller, add a corresponding class variable to hold the first view controller object:
class SecondViewController: UIViewController {
var firstViewController: FirstViewController!
That way you can access its values within FirstViewController like so:
let row = firstViewController.picker.selectedRowInComponent(0)
post["house"] = firstViewController.pickerData[row]
If you're using a UINavigationController without a storyboard, you can similarly set the SecondViewController's FirstViewController variable upon the SecondViewController's creation, ex:
SecondViewController *secondViewController = [[SecondViewController alloc] init];
secondViewController.firstViewController = self;
[self.navigationController pushViewController:secondViewController animated:YES];