107  

Swift 4

alert.addTextField(configurationHandler: { (textField) in
    textField.placeholder = "Enter First Name"
})

Use this code, I am running this code in my app successfully.

使用此代码，我在我的应用程序中成功地运行这段代码。

@IBAction func addButtonClicked(sender : AnyObject){
    let alertController = UIAlertController(title: "Add New Name", message: "", preferredStyle: UIAlertControllerStyle.Alert)
    alertController.addTextFieldWithConfigurationHandler { (textField : UITextField!) -> Void in
        textField.placeholder = "Enter Second Name"
    }
    let saveAction = UIAlertAction(title: "Save", style: UIAlertActionStyle.Default, handler: { alert -> Void in
        let firstTextField = alertController.textFields![0] as UITextField
        let secondTextField = alertController.textFields![1] as UITextField
    })
    let cancelAction = UIAlertAction(title: "Cancel", style: UIAlertActionStyle.Default, handler: {
        (action : UIAlertAction!) -> Void in })
    alertController.addTextFieldWithConfigurationHandler { (textField : UITextField!) -> Void in
        textField.placeholder = "Enter First Name"
    }

    alertController.addAction(saveAction)
    alertController.addAction(cancelAction)

    self.presentViewController(alertController, animated: true, completion: nil)
}

Edited: Swift 3.0 version

编辑:斯威夫特3.0版本

@IBAction func addButtonClicked(_ sender: UIButton){
    let alertController = UIAlertController(title: "Add New Name", message: "", preferredStyle: .alert)
    alertController.addTextField { (textField : UITextField!) -> Void in
        textField.placeholder = "Enter Second Name"
    }
    let saveAction = UIAlertAction(title: "Save", style: .default, handler: { alert -> Void in
        let firstTextField = alertController.textFields![0] as UITextField
        let secondTextField = alertController.textFields![1] as UITextField
        print("firstName \(firstTextField.text), secondName \(secondTextField.text)")
    })
    let cancelAction = UIAlertAction(title: "Cancel", style: .default, handler: { (action : UIAlertAction!) -> Void in })
    alertController.addTextField { (textField : UITextField!) -> Void in
        textField.placeholder = "Enter First Name"
    }

    alertController.addAction(saveAction)
    alertController.addAction(cancelAction)

    self.present(alertController, animated: true, completion: nil)
}

17  

To add a text field in Swift 3.0:

在Swift 3.0中添加文本字段:

let alertController = UIAlertController(title: "Title", message: "", preferredStyle: .alert)
alertController.addAction(UIAlertAction(title: "Save", style: .default, handler: { alert -> Void in
    let textField = alertController.textFields![0] as UITextField
    // do something with textField
}))
alertController.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
alertController.addTextField(configurationHandler: {(textField : UITextField!) -> Void in
    textField.placeholder = "Search"
})   
self.present(alertController, animated: true, completion: nil)

10  

So I started checking to see what could possibly have been different in my code to the working code. I noticed that my ViewController extends

所以我开始检查我的代码与工作代码有什么不同。我注意到我的ViewController扩展了

UITextFieldDelegate

Which apparently means that I need to set the delegate of any child UITextView:

这显然意味着我需要设置任何子UITextView的委托:

alertController.addTextFieldWithConfigurationHandler { (textField) -> Void in
        searchTextField = textField
        searchTextField?.delegate = self //REQUIRED
        searchTextField?.placeholder = "Enter your search terms"
}

3  

How to add textField to AlertView? Let's keep it short and simple.

如何向AlertView添加textField ?让我们保持简短。

This works for Swift 3.0 and above.

这适用于Swift 3.0及以上版本。

var nameField: UITextField?
let alertController = UIAlertController(title: "Add Number", message: nil, preferredStyle: .alert)
// Add textfield to alert view
alertController.addTextField { (textField) in
    nameField = textField
}

First, you instantiate an object of UIAlertController and then you add a text field to it by accessing addTextField member of UIAlertController class.

首先，实例化UIAlertController的对象，然后通过访问UIAlertController类的addTextField成员将文本字段添加到它。

2  

add TextField to UIAlertController and TextField text Display on UILabel in Swift

将TextField添加到UIAlertController，并在UILabel上以Swift格式显示TextField文本

let alert = UIAlertController(title: "Alert", message: "", preferredStyle: .alert)

alert.addTextField { (textField) in
textField.placeholder = "First Name"
}
alert.addAction(UIAlertAction(title: "OK", style: .default, handler: { [weak alert] (_) in
let textField = alert?.textFields![0]
self.label.text = textField?.text  }))

self.present(alert, animated: true, completion: nil)

1  

Great answer a slight modification to show how the textfield can be used:

伟大的答案一个微小的修改显示如何使用textfield:

func addRow (row: Int, bodin: String, flag: Int) {
    let alertController = UIAlertController(title: bodin, message: "", preferredStyle: .alert)
    alertController.addAction(UIAlertAction(title: "Save", style: .default, handler: {
        alert -> Void in
        _ = alertController.textFields![0] as UITextField

    }))
    alertController.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))

    alertController.addTextField(configurationHandler: {(textField : UITextField!) -> Void in
        switch flag {
        case 0:
            textField.keyboardType = UIKeyboardType.phonePad
            textField.placeholder = "Enter Number"
        case 1:
            textField.keyboardType = UIKeyboardType.emailAddress
            textField.placeholder = "Enter Email"
        default:
            break
        }

    })

0  

For Swift 4.0, You can use this sample of code succesfully tested in my project:

对于Swift 4.0，您可以在我的项目中使用这个成功测试过的代码示例:

@IBAction func withdrawTapped(_ sender: UIButton) {

  let alertController = UIAlertController(title: "Token withdraw", message: "", preferredStyle: .alert)

  let withdrawAction = UIAlertAction(title: "Withdraw", style: .default) { (aciton) in

    let text = alertController.textFields!.first!.text!

    if !text.isEmpty {
      self.presentAlert(
        title: "Succesful", 
        message: "You made request for withdraw \(textField.text) tokens")
    }
  }

  let cancelAction = UIAlertAction(title: "Cancel", style: .cancel) { (action) in
  }

  alertController.addTextField { (textField) in
    textField.placeholder = "999"
    textField.keyboardType = .decimalPad
  }

  alertController.addAction(withdrawAction)
  alertController.addAction(cancelAction)

  self.present(alertController, animated: true, completion: nil)
}