How to display alert when the value of textfield is 0 in swift4?

Question

I want to display an alert when the value of textfield is 0. However, putting a value of 0 in the textfield does not show the alert.

How can I solve the problem?

@IBOutlet var priceTextfield: UITextField!

if Int(priceTextfield.text!) == 0 {

   let aert = UIAlertController(title: "OK", message: "Price must be greater than 0.", preferredStyle: .alert)
   let ok = UIAlertAction(title: "OK", style: .default)
   alert.addAction(OK)

   self.present(alert, animated: false)
}

Answered here: https://stackoverflow.com/questions/28394933/how-do-i-check-when-a-uitextfield-changes — Mike Koene, Nov 28 '18 at 14:14

Rakesha Shastri · Accepted Answer · 2018-11-28T16:28:54.547

1

You should handle this is textFieldShouldEndEditing delegate.

func textFieldShouldEndEditing(_ textField: UITextField) -> Bool {
    if Double(textField.text!) == 0 {
        // Show alert
        return false
    }
    return true
}

Note: Your view controller needs to conform to the UITextFieldDelegate and the text field delegate has to be set.

class YourViewController: UIViewController, UITextFieldDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()

        priceTextfield.delegate = self
    }

}

edited Nov 28 '18 at 16:28

answered Nov 28 '18 at 13:47

Rakesha Shastri

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Thank you every time :) – dinggu Nov 28 '18 at 15:47

Kathiresan Murugan · Answer 2 · 2018-11-28T14:07:57.667

1

   func textFieldShouldEndEditing(_ textField: UITextField) -> Bool {

    if textField.text.count > 1 {
     if let value = Int(textField.text), value == 0 { // Convert string to Int
                    // Show alert
         }
       }

     return true
  }

edited Nov 28 '18 at 14:07

answered Nov 28 '18 at 13:55

Kathiresan Murugan

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3
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44

what the difference between your answer and shasthri answer – Anbu.Karthik Nov 28 '18 at 13:56
converted string to Int, Because Question was asked check with zero. – Kathiresan Murugan Nov 28 '18 at 13:57
UItextField text property it is an optional String. You need to unwrap its value. `Int(textField.text!)` – Leo Dabus Nov 28 '18 at 14:00
Btw text has a default value of an empty string. Even if you assign nil before trying to access its value it will return `""`. So it is ok to force unwrap its value. – Leo Dabus Nov 28 '18 at 14:04

How to display alert when the value of textfield is 0 in swift4?

2 Answers2