如何在Swift

时间：2015-08-10 14:33:22

标签： ios swift uitextfield uialertcontroller

我正在尝试使用UIAlertController显示UITextView。当我添加这一行时：

    //Add text field
    alertController.addTextFieldWithConfigurationHandler { (textField) -> Void in
    }

我收到Runtime错误：

  

致命错误：在解包可选值时意外发现nil 

    let alertController: UIAlertController = UIAlertController(title: "Find image", message: "Search for image", preferredStyle: .Alert)

    //cancel button
    let cancelAction: UIAlertAction = UIAlertAction(title: "Cancel", style: .Cancel) { action -> Void in
        //cancel code
    }
    alertController.addAction(cancelAction)

    //Create an optional action
    let nextAction: UIAlertAction = UIAlertAction(title: "Search", style: .Default) { action -> Void in
        let text = (alertController.textFields?.first as! UITextField).text
        println("You entered \(text)")
    }
    alertController.addAction(nextAction)

    //Add text field
    alertController.addTextFieldWithConfigurationHandler { (textField) -> Void in
        textField.textColor = UIColor.greenColor()
    }
    //Present the AlertController
    presentViewController(alertController, animated: true, completion: nil)

这是通过ViewController在IBAction内显示的。

我已经从here下载了代码并且工作正常。我将该方法复制并粘贴到我的代码中，然后中断了。 自我在最后一行的存在没有影响。

14 个答案:

答案 0 :(得分：150)

Swift 4 

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

使用此代码，我在我的应用中成功运行此代码。

@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)
}

编辑：Swift 3.0版

@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)
}

答案 1 :(得分：21)

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)

答案 2 :(得分：11)

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

UITextFieldDelegate

这显然意味着我需要设置任何子UITextView的代理：

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

答案 3 :(得分：4)

如何将textField添加到AlertView？让我们保持简短。

适用于Swift 3.0及更高版本。

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

首先，您实例化UIAlertController的对象，然后通过访问addTextField类的UIAlertController成员向其添加文本字段。

答案 4 :(得分：3)

解决方案：

Swift 4.2

尝试以下几行，看看是否有效：

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
    })
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)

希望有帮助。

答案 5 :(得分：2)

对于Swift 4.0，您可以在我的项目中使用这个成功测试的代码示例：

@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)
}

答案 6 :(得分：1)

很好的回答稍作修改，以显示如何使用文本字段：

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
        }

    })

答案 7 :(得分：1)

将TextField添加到UIAlertController和TextField文本显示在Swift中的UILabel上

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)

答案 8 :(得分：1)

在Swift 4.2和Xcode 10.1中

具有两个文本字段和读取文本字段文本数据并在所有视图顶部显示警报的警报。

func alertWithTF(title: String, message: String) {
    //Step : 1
    let alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.alert)

    //Step : 2
    alert.addAction (UIAlertAction(title: "Save", style: .default) { (alertAction) in
        let textField = alert.textFields![0]
        let textField2 = alert.textFields![1]
        if textField.text != "" {
            //Read textfield data
            print(textField.text!)
            print("TF 1 : \(textField.text!)")
        } else {
            print("TF 1 is Empty...")
        }
        if textField2.text != "" {
            //Read textfield data
            print(textField2.text!)
            print("TF 2 : \(textField2.text!)")
        } else {
            print("TF 2 is Empty...")
        }
    })

    //Step : 3
    //For first TF
    alert.addTextField { (textField) in
        textField.placeholder = "Enter your first name"
        textField.textColor = .red
    }
    //For second TF
    alert.addTextField { (textField) in
        textField.placeholder = "Enter your last name"
        textField.textColor = .blue
    }

    //Cancel action
    alert.addAction(UIAlertAction(title: "Cancel", style: .default) { (alertAction) in })
   self.present(alert, animated:true, completion: nil)

}

如果要在所有视图之上显示aleert。

从上面的代码中删除最后一行self.present(alert, animated:true, completion: nil)，并添加下面的代码。

//Present alert on top of all views.
let alertWindow = UIWindow(frame: UIScreen.main.bounds)
alertWindow.rootViewController = UIViewController()
alertWindow.windowLevel = UIWindowLevelAlert + 1

alertWindow.makeKeyAndVisible()

alertWindow.rootViewController?.present(alert, animated:true, completion: nil)

现在这样通话

alertWithTF(title: "This is title", message: "This is message")

答案 9 :(得分：1)

使用一个textField添加SwiftController（Swift 5） 

func openAlert(){
    let alertController = UIAlertController(title: "Title", message: "", preferredStyle: .alert)
    alertController.addTextField { (textField : UITextField!) -> Void in
        textField.placeholder = "Enter name"
    }

    let saveAction = UIAlertAction(title: kAlertConfirm, style: .default, handler: { alert -> Void in
        if let textField = alertController.textFields?[0] {
            if textField.text!.count > 0 {
                print("Text :: \(textField.text ?? "")")
            }
        }
    })

    let cancelAction = UIAlertAction(title: kAlertCancel, style: .default, handler: {
        (action : UIAlertAction!) -> Void in })

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

    alertController.preferredAction = saveAction

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

答案 10 :(得分：1)

UIAlertController和UITextfield最新的 Apple Swift版本5.1.3

在您的{{1}中创建lazy的{​​{1}} 变量，添加UIAlertController，在UIViewController上显示警报操作： 

UITextFieldDelegate

快乐编码！！ ：）

答案 11 :(得分：0)

Swift5

第一类遵循UITextFieldDelegate，然后创建新的textField属性

    private var myTextField : UITextField?

    // now where u want to add code
    let alertContoller = UIAlertController.init(title: "Add", message: "My message to user", preferredStyle: .alert)
    alertContoller.addTextField { (textField) in
        // make sure your outside any property should be accessed with self here
        self.myTextField = textField
        //Important step assign textfield delegate to self
        self.myTextField?.delegate = self 
        self.myTextField?.placeholder = self.textFieldPlaceholderText
    }
    let action = UIAlertAction.init(title: "Ok", style: .default) { action in
        print("Alert tapped")
    }
    alertContoller.addAction(action)
    present(alertContoller, animated: true, completion:nil)

谢谢

答案 12 :(得分：0)

private func showLoginAlert() {
    let loginAlert = UIAlertController(title: "Login Using Credentials", message: nil, preferredStyle: .alert)
    loginAlert.view.tintColor = .systemBlue

    loginAlert.addTextField { usernameField in
        usernameField.font = .systemFont(ofSize: 17.0)
        usernameField.placeholder = "Username"
    }
    loginAlert.addTextField { passwordField in
        passwordField.font = .systemFont(ofSize: 17.0)
        passwordField.isSecureTextEntry = true
        passwordField.placeholder = "Password"
    }

    let cancelAction = UIAlertAction(title: "Cancel",
                                     style: .destructive,
                                     handler: { _ in
                                        // self.handleUsernamePasswordCanceled(loginAlert: loginAlert)
    })
    loginAlert.addAction(cancelAction)

    let loginAction = UIAlertAction(title: "Login",
                                    style: .default,
                                    handler: { _ in
                                        // self.handleUsernamePasswordEntered(loginAlert: loginAlert)
    })
    loginAlert.addAction(loginAction)
    loginAlert.preferredAction = loginAction
    present(loginAlert, animated: true, completion: nil)
}

快速5

答案 13 :(得分：-1)

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