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Passing Data between View Controllers in Swift

Posted by: admin November 30, 2017 Leave a comment

Questions:

I am trying to convert an app from Objective-C to Swift but I can’t find how to pass data between views using Swift. My Objective-C code is

UIStoryboard *storyBoard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
AnsViewController *ansViewController;
ansViewController = [storyBoard instantiateViewControllerWithIdentifier:@"ansView"];
ansViewController.num = theNum;
[self presentViewController:ansViewController animated:YES completion:nil];

What that is doing is it basically takes the variable, theNum, and passes it to the variable, num, on a different view controller. I know this may be an easy question but I am getting pretty confused with Swift so if someone could explain how they changed it to Swift that would be greatly appreciated!

Thanks

Answers:

Let’s assumed we stand at the firstView go to the DetailView and want passing data from firstView to Detailview. To do that with storyboard, at the firstView we will have a method:

override func prepareForSegue(segue: UIStoryboardSegue!, sender: AnyObject!) {
    if (segue.identifier == "segueTest") {
      //Checking identifier is crucial as there might be multiple
      // segues attached to same view
      var detailVC = segue!.destinationViewController as DetailViewController;
      detailVC.toPass = textField.text
    }
}

and then into the class of DetailView we declared a variable:

var toPass: String!

then you can use the variable toPass (of course you can change the type of the variable as you want, in this EX I just demo for string type).

Questions:
Answers:
class AnsViewController: UIViewController {
   var theNum: Int

    override func viewDidLoad() {
        super.viewDidLoad()

        println(theNum)
    }

}

override func tableView(tableView: UITableView!, didSelectRowAtIndexPath indexPath: NSIndexPath!) {
    let viewController = self.storyboard.instantiateViewControllerWithIdentifier("ansView") as AnsViewController
    viewController.num = theNum
    self.presentViewController(viewController, animated: true, completion: nil)
}

Questions:
Answers:

To pass string or any data from one controller to another in swift.

Follows below steps:

1) Create property in child controller as var abc:string!

2) Create object of childcontroller

let storyboard:UIStoryboard()
let viewController: childcontroller = storyboard.instantiateViewControllerWithIdentifier("childcontroller") as! childcontroller
viewController.abc = "hello";
self.navigationController.pushviewController(Controller:viewController animated:true CompletionHandler:nil)

Questions:
Answers:
Using tableview,

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath)
        {
            let ClubProfileView = self.storyboard?.instantiateViewController(withIdentifier: "CBClubProfileViewController") as! CBClubProfileViewController

            let TempCulubDic:NSDictionary =
                ((ClubsListbyDateDic.object(forKey:((ClubsListbyDateDic.allKeys as! [String]).sorted(by: <)as NSArray).object(at: indexPath.section) as! String) as! NSArray).object(at: indexPath.row))as! NSDictionary

            let ClubId:String=(TempCulubDic.value(forKey: "club_id") as? String)!

            let CheckIndate:String=(TempCulubDic.value(forKey: "chekin_date") as? String)!

            ClubProfileView.ClubID=ClubId

            ClubProfileView.CheckInDate = CheckIndate

            // self.tabBarController?.tabBar.isHidden=true

            ClubProfileView.hidesBottomBarWhenPushed = true
            self.navigationController?.pushViewController(ClubProfileView, animated: true)
            }

Questions:
Answers:
     @IBAction func nextbtnpreesd(_ sender: Any) {

            let mystring = "2"
            performSegue(withIdentifier: "MusicVC", sender: mystring)
        }



override func prepare(for segue: UIStoryboardSegue, sender: Any?) {


        if let destination = segue.destination as? MusicVC{

            if let song = sender as? String{
                destination.strlablevalie = song
            }
        }
    }

//in MusicVC create string like:

 var strlablevalie:String!

Questions:
Answers:

Note: if we are using storyboard

Step 1: Master controller :

    // table row which row was selected
    func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath!) {
        tableView.deselectRowAtIndexPath(indexPath, animated: true)

        println("You selected cell #\(indexPath.row)!")

        nextScreenRow = indexPath.row

        // get to the next screen
        self.performSegueWithIdentifier("dashboard_static_screen_segue", sender: self)

    }

and then;

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {

        if (segue.identifier == "dashboard_static_screen_segue") {
            var detailController = segue.destinationViewController as StaticScreens;
            detailController.screenNumber = nextScreenRow
        }

    }// end prepareForSegue

step 2: Detail controller (StaticScreen)

// set variable into your detail controller

var screenNumber: NSInteger?

println("selected row \(screenNumber!)")