Ios 如何交替检查swift中的所有uitextfields？

我是swift编程语言的初学者。我正在寻找检查所有文本字段的替代方法。我想做的是。若文本字段并没有任何值，则将文本字段文本更改为红色文本字段名称，并向用户发送警报。如果用户开始键入chance文本，请将其颜色恢复为黑色

这是我的方法，但我认为这不是正确的方法

func alertMessage(title:String, message:String)->Void{

    var alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.Alert)
        alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler: nil))

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

}

func checkAllFields()->Void{



    var allFields=[String:String]()
    var fieldCounter = 0


    allFields = ["Username":userNameField.text,"Name":nameField.text,"Surname":surNameField.text,"Email":emailField.text, "Password":passwordField.text]

    for (field, fieldData) in allFields{

        if fieldData.isEmpty{

            fieldCounter++
        }

    }

    if fieldCounter <= allFields.count{

        var title = "Missing Fields"
        var message = "You need to fill all fields."

        if userNameField.text.isEmpty{

            userNameField.textColor = UIColor.redColor()
            userNameField.text = "Username"

        }

        if nameField.text.isEmpty{

            nameField.textColor = UIColor.redColor()
            nameField.text = "Name"


        }

        if surNameField.text.isEmpty{

            surNameField.textColor = UIColor.redColor()
            surNameField.text = "Surname"

        }

        if emailField.text.isEmpty {

        emailField.textColor = UIColor.redColor()
        emailField.text = "Email"

        }

        if passwordField.text.isEmpty  {

        passwordField.textColor = UIColor.redColor()
        passwordField.text = "Password"

        }

        if retypePasswordField.text.isEmpty{
        retypePasswordField.textColor = UIColor.redColor()
        retypePasswordField.text = "Retype Password"
        }

        alertMessage(title, message: message)



    }



}

func alertMessage（标题：String，消息：String）->Void{
var alert=UIAlertController（标题：标题，消息：消息，首选样式：UIAlertControllerStyle.alert）
addAction（UIAlertAction（标题：“确定”，样式：UIAlertActionStyle.Default，处理程序：nil））
self.presentViewController（警报、动画：true、完成：nil）
}
func checkAllFields（）->Void{
var allFields=[String:String]（）
变量字段计数器=0
allFields=[“用户名”：userNameField.text，“名称”：nameField.text，“姓氏”：nameField.text，“电子邮件”：emailField.text，“密码”：passwordField.text]
用于所有字段中的（字段，字段数据）{
如果fieldData.i为空{
现场计数器++
}
}
如果fieldCounter我建议通过获取UITextView而不是其内容来简化代码：

func checkAllFields()->Void{

var allFields=[String:UITextView]()
var fieldCounter = 0


allFields = ["Username":userNameField, "Name":nameField, "Surname":surNameField, "Email":emailField, "Password":passwordField]

for (fieldName, fieldTextView) in allFields{

    if fieldTextView.text.isEmpty{
        fieldTextView.textColor = UIColor.redColor()
        fieldTextView.text = fieldName
        fieldCounter++

    }

}

if fieldCounter > 0 {

    var title = "Missing Fields"
    var message = "You need to fill all fields."

    alertMessage(title, message: message)

}