CODEWITHSUNDEEP
iosswift
Mo Code
Mo Code

Reputation: 117

Swift how to update label in previous view controller

I want to update the label in my DashboardViewController from my AccountViewController when the back button is pressed in AccountViewController.

I have tried passing back a variable from 2nd view to 1st view and updating the label in viewDidLoad and in viewWillAppear but it never updates the label when the 1st view is back on screen.

I tried creating a function in 1st view to update the label with a string passed into the function and calling that function from 2nd view but it says that the label is nil so it couldn't be updated.

My latest attempt was to create a delegate but that didn't work either.

Here is my delegate attempt.

 class DashboardViewController: UIViewController, AccountViewControllerDelegate {
 @IBOutlet weak var welcome_lbl: UILabel!

    func nameChanged(name: String){
    var full_name = "Welcome \(name)"
    welcome_lbl.text = "\(full_name)"
}
    override func viewDidLoad() {
    super.viewDidLoad()

    AccountViewController.delegate = self
}
}

And then in my AccountViewController I have this 

protocol AccountViewControllerDelegate{
func name_changed(name: String)
}

class AccountViewController: UIViewController, UITextFieldDelegate {
   var info_changed = false
static var delegate: AccountViewControllerDelegate!
    @IBAction func back_btn(sender: AnyObject) {
    if(info_changed){
        AccountViewController.delegate.name_changed(name_tf.text!)
    }
    self.dismissViewControllerAnimated(true, completion: nil)
}

Did I mess up the delegate process somehow ? Or is there an easier way to do this?

Upvotes: 0

Views: 2924

Answers (1)

Dan Jiang
Dan Jiang

Reputation: 99

First. Your delegate should be a normal property of AccountViewController. There is no need to update your name when user press back. You can change DashboardViewController`s name when user change name in AccountViewController. When user go back to DashboardViewController. It`s already show the changed name.

protocol AccountViewControllerDelegate{
    func name_changed(name: String)
}

class AccountViewController: UIViewController, UITextFieldDelegate {

  var delegate: AccountViewControllerDelegate?

    // when user change name through textfield or other control
    func changeName(name: String) {
        delegate?.name_changed(name)
    }

}

Second. When DashboardViewController show AccountViewController. I think it should be push. Set DashboardViewController instance be AccountViewController instance`s delegate.

class DashboardViewController: UIViewController, AccountViewControllerDelegate {
    @IBOutlet weak var welcome_lbl: UILabel!

    func nameChanged(name: String){
    var full_name = "Welcome \(name)"
    welcome_lbl.text = "\(full_name)"
    }

    // present or push to AccountViewController
    func showAccountViewController {
        let accountViewController = AccountViewController()
        accountViewController.delegate = self
        // do push view controller
    }
}

Upvotes: 2

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