使用 UITextField Popup Alertview 获取文本 Swift 3 fatal error

Question

我有弹出式警报并使用 UITextField 代码获取文本，但是当我想要获取文本字符串时却出现 nil 错误。我的代码在这里。我正在使用 Xcode latest 和 Swift 3.

   var tField: UITextField!


   @IBAction func addcommentButtonTapped(sender: AnyObject) {


    let alert = UIAlertController(title: "Write Comment", message: "", preferredStyle: UIAlertControllerStyle.alert)

    alert.addTextField { (configurationTextField) in

    alert.addAction(UIAlertAction(title: "Cancel", style: UIAlertActionStyle.cancel, handler:self.handleCancel))
    alert.addAction(UIAlertAction(title: "Send", style: UIAlertActionStyle.default, handler:{ (UIAlertAction)in
    print("Done !!")


       let textField = self.tField.text // HERE GIVES ERROR nil = tField


        if  textField != nil {
              print("Item : \(textField))")
        }



    }))
    self.present(alert, animated: true, completion: {
    print("completion block")
    })

    }

    }

错误

fatal error: unexpectedly found nil while unwrapping an Optional value

错误行

let textField = self.tField.text // HERE GIVES ERROR nil = tField

谢谢！

Answer 1

您已将 alert action 添加到 addTextField 闭包中，您还需要使用 alertController 的文本字段数组中的第一个文本字段，因此您需要更改你的代码是这样的

@IBAction func addcommentButtonTapped(sender: AnyObject) {

   let alert = UIAlertController(title: "Write Comment", message: "", preferredStyle: UIAlertControllerStyle.alert)
   alert.addAction(UIAlertAction(title: "Cancel", style: UIAlertActionStyle.cancel, handler:self.handleCancel))
   alert.addTextField { (configurationTextField) in
       //configure here your textfield
       configurationTextField.textColor = UIColor.greenColor()
   }
   alert.addAction(UIAlertAction(title: "Send", style: UIAlertActionStyle.default, handler:{ (UIAlertAction)in
       print("Done !!")
       if let textField = alert.textFields?.first {
           print("Item : \(textField.text))")
       }
   }))
   self.present(alert, animated: true, completion: {
       print("completion block")
   })    
}

使用 UITextField Popup Alertview 获取文本 Swift 3 fatal error

Getting text with UITextField Popup Alertview with Swift 3 fatal error

uitextfield

ios

swift3