如何检查swift中的文本字段是否为空

我正在处理下面的代码，以检查

textField1

和

textField2

文本字段中是否有任何输入

按下按钮时，

IF

语句没有执行任何操作

 @IBOutlet var textField1 : UITextField = UITextField()
 @IBOutlet var textField2 : UITextField = UITextField()
 @IBAction func Button(sender : AnyObject) 
  {

    if textField1 == "" || textField2 == "" 
      {

  //then do something

      }  
  }

---

简单地将textfield对象与空字符串

“

进行比较不是正确的方法。您必须比较textfield的

text

属性，因为它是兼容的类型，并且保存您要查找的信息

@IBAction func Button(sender: AnyObject) {
    if textField1.text == "" || textField2.text == "" {
        // either textfield 1 or 2's text is empty
    }
}

Swift 2.0:

防护装置：

guard let text = descriptionLabel.text where !text.isEmpty else {
    return
}
text.characters.count  //do something if it's not empty

if let text = descriptionLabel.text where !text.isEmpty
{
    //do something if it's not empty  
    text.characters.count  
}

guard let text = descriptionLabel.text, !text.isEmpty else {
    return
}
text.characters.count  //do something if it's not empty

if let text = descriptionLabel.text, !text.isEmpty
{
    //do something if it's not empty  
    text.characters.count  
}

if let _text = theTextField.text, _text.isEmpty {
    // _text is not empty here
}

if let theText = theTextField.text where !theTextField.text!.isEmpty {
    // theText is not empty here
}

guard let theText = theTextField.text where theText.isEmpty else {
    // theText is empty
    return // or throw
}

// you can use theText outside the guard scope !
print("user wrote \(theText)")

guard let theText = theTextField.text where !theTextField.text!.isEmpty else {
    // the text is empty
    return
}

// you can use theText outside the guard scope !
print("user wrote \(theText)")

如果：

guard let text = descriptionLabel.text where !text.isEmpty else {
    return
}
text.characters.count  //do something if it's not empty

if let text = descriptionLabel.text where !text.isEmpty
{
    //do something if it's not empty  
    text.characters.count  
}

guard let text = descriptionLabel.text, !text.isEmpty else {
    return
}
text.characters.count  //do something if it's not empty

if let text = descriptionLabel.text, !text.isEmpty
{
    //do something if it's not empty  
    text.characters.count  
}

if let _text = theTextField.text, _text.isEmpty {
    // _text is not empty here
}

if let theText = theTextField.text where !theTextField.text!.isEmpty {
    // theText is not empty here
}

guard let theText = theTextField.text where theText.isEmpty else {
    // theText is empty
    return // or throw
}

// you can use theText outside the guard scope !
print("user wrote \(theText)")

guard let theText = theTextField.text where !theTextField.text!.isEmpty else {
    // the text is empty
    return
}

// you can use theText outside the guard scope !
print("user wrote \(theText)")

Swift 3.0:

防护装置：

guard let text = descriptionLabel.text where !text.isEmpty else {
    return
}
text.characters.count  //do something if it's not empty

if let text = descriptionLabel.text where !text.isEmpty
{
    //do something if it's not empty  
    text.characters.count  
}

guard let text = descriptionLabel.text, !text.isEmpty else {
    return
}
text.characters.count  //do something if it's not empty

if let text = descriptionLabel.text, !text.isEmpty
{
    //do something if it's not empty  
    text.characters.count  
}

if let _text = theTextField.text, _text.isEmpty {
    // _text is not empty here
}

if let theText = theTextField.text where !theTextField.text!.isEmpty {
    // theText is not empty here
}

guard let theText = theTextField.text where theText.isEmpty else {
    // theText is empty
    return // or throw
}

// you can use theText outside the guard scope !
print("user wrote \(theText)")

guard let theText = theTextField.text where !theTextField.text!.isEmpty else {
    // the text is empty
    return
}

// you can use theText outside the guard scope !
print("user wrote \(theText)")

如果：

guard let text = descriptionLabel.text where !text.isEmpty else {
    return
}
text.characters.count  //do something if it's not empty

if let text = descriptionLabel.text where !text.isEmpty
{
    //do something if it's not empty  
    text.characters.count  
}

guard let text = descriptionLabel.text, !text.isEmpty else {
    return
}
text.characters.count  //do something if it's not empty

if let text = descriptionLabel.text, !text.isEmpty
{
    //do something if it's not empty  
    text.characters.count  
}

if let _text = theTextField.text, _text.isEmpty {
    // _text is not empty here
}

if let theText = theTextField.text where !theTextField.text!.isEmpty {
    // theText is not empty here
}

guard let theText = theTextField.text where theText.isEmpty else {
    // theText is empty
    return // or throw
}

// you can use theText outside the guard scope !
print("user wrote \(theText)")

guard let theText = theTextField.text where !theTextField.text!.isEmpty else {
    // the text is empty
    return
}

// you can use theText outside the guard scope !
print("user wrote \(theText)")

---

更好更美观的使用

 @IBAction func Button(sender: AnyObject) {
    if textField1.text.isEmpty || textField2.text.isEmpty {

    }
}

---

也许我有点晚了，但我们不能这样检查一下：

   @IBAction func Button(sender: AnyObject) {
       if textField1.text.utf16Count == 0 || textField2.text.utf16Count == 0 {

       }
    }

if ((textField.text ?? "").isEmpty) {
    // is empty
}

---

我只是想用一个简单的代码向您展示解决方案

@IBAction func Button(sender : AnyObject) {
 if textField1.text != "" {
   // either textfield 1 is not empty then do this task
 }else{
   //show error here that textfield1 is empty
 }
}

---

签入实时文本字段源的另一种方法：

 @IBOutlet var textField1 : UITextField = UITextField()

 override func viewDidLoad() 
 {
    ....
    self.textField1.addTarget(self, action: Selector("yourNameFunction:"), forControlEvents: UIControlEvents.EditingChanged)
 }

 func yourNameFunction(sender: UITextField) {

    if sender.text.isEmpty {
      // textfield is empty
    } else {
      // text field is not empty
    }
  }

---

Swift 2/Xcode 7的小巧宝石

@IBAction func SubmitAgeButton(sender: AnyObject) {

    let newAge = String(inputField.text!)        

if ((textField.text?.isEmpty) != false) {
        label.text = "Enter a number!"
    }
    else {
        label.text = "Oh, you're \(newAge)"

        return
    }

    }

如果让。。。哪里{ Swift 3：

guard let text = descriptionLabel.text where !text.isEmpty else {
    return
}
text.characters.count  //do something if it's not empty

if let text = descriptionLabel.text where !text.isEmpty
{
    //do something if it's not empty  
    text.characters.count  
}

guard let text = descriptionLabel.text, !text.isEmpty else {
    return
}
text.characters.count  //do something if it's not empty

if let text = descriptionLabel.text, !text.isEmpty
{
    //do something if it's not empty  
    text.characters.count  
}

if let _text = theTextField.text, _text.isEmpty {
    // _text is not empty here
}

if let theText = theTextField.text where !theTextField.text!.isEmpty {
    // theText is not empty here
}

guard let theText = theTextField.text where theText.isEmpty else {
    // theText is empty
    return // or throw
}

// you can use theText outside the guard scope !
print("user wrote \(theText)")

guard let theText = theTextField.text where !theTextField.text!.isEmpty else {
    // the text is empty
    return
}

// you can use theText outside the guard scope !
print("user wrote \(theText)")

Swift 2：

guard let text = descriptionLabel.text where !text.isEmpty else {
    return
}
text.characters.count  //do something if it's not empty

if let text = descriptionLabel.text where !text.isEmpty
{
    //do something if it's not empty  
    text.characters.count  
}

guard let text = descriptionLabel.text, !text.isEmpty else {
    return
}
text.characters.count  //do something if it's not empty

if let text = descriptionLabel.text, !text.isEmpty
{
    //do something if it's not empty  
    text.characters.count  
}

if let _text = theTextField.text, _text.isEmpty {
    // _text is not empty here
}

if let theText = theTextField.text where !theTextField.text!.isEmpty {
    // theText is not empty here
}

guard let theText = theTextField.text where theText.isEmpty else {
    // theText is empty
    return // or throw
}

// you can use theText outside the guard scope !
print("user wrote \(theText)")

guard let theText = theTextField.text where !theTextField.text!.isEmpty else {
    // the text is empty
    return
}

// you can use theText outside the guard scope !
print("user wrote \(theText)")

守卫…还有什么地方{ 您还可以使用关键字

guard

：

Swift 3：

guard let text = descriptionLabel.text where !text.isEmpty else {
    return
}
text.characters.count  //do something if it's not empty

if let text = descriptionLabel.text where !text.isEmpty
{
    //do something if it's not empty  
    text.characters.count  
}

guard let text = descriptionLabel.text, !text.isEmpty else {
    return
}
text.characters.count  //do something if it's not empty

if let text = descriptionLabel.text, !text.isEmpty
{
    //do something if it's not empty  
    text.characters.count  
}

if let _text = theTextField.text, _text.isEmpty {
    // _text is not empty here
}

if let theText = theTextField.text where !theTextField.text!.isEmpty {
    // theText is not empty here
}

guard let theText = theTextField.text where theText.isEmpty else {
    // theText is empty
    return // or throw
}

// you can use theText outside the guard scope !
print("user wrote \(theText)")

guard let theText = theTextField.text where !theTextField.text!.isEmpty else {
    // the text is empty
    return
}

// you can use theText outside the guard scope !
print("user wrote \(theText)")

Swift 2：

guard let text = descriptionLabel.text where !text.isEmpty else {
    return
}
text.characters.count  //do something if it's not empty

if let text = descriptionLabel.text where !text.isEmpty
{
    //do something if it's not empty  
    text.characters.count  
}

guard let text = descriptionLabel.text, !text.isEmpty else {
    return
}
text.characters.count  //do something if it's not empty

if let text = descriptionLabel.text, !text.isEmpty
{
    //do something if it's not empty  
    text.characters.count  
}

if let _text = theTextField.text, _text.isEmpty {
    // _text is not empty here
}

if let theText = theTextField.text where !theTextField.text!.isEmpty {
    // theText is not empty here
}

guard let theText = theTextField.text where theText.isEmpty else {
    // theText is empty
    return // or throw
}

// you can use theText outside the guard scope !
print("user wrote \(theText)")

guard let theText = theTextField.text where !theTextField.text!.isEmpty else {
    // the text is empty
    return
}

// you can use theText outside the guard scope !
print("user wrote \(theText)")

这对于验证链尤其适用，例如表单。您可以为每次验证编写一个

保护let

，如果出现严重错误，则返回或抛出异常。

检查的简单方法

if TextField.stringValue.isEmpty {

}

---

太晚了，在Xcode 7.3.1中工作正常

if _txtfield1.text!.isEmpty || _txtfield2.text!.isEmpty {
        //is empty
    }

---

好的，这可能已经晚了，但在Xcode 8中我有一个解决方案：

if(textbox.stringValue.isEmpty) {
    // some code
} else {
    //some code
}

---

我使用了

uikeyinport

的内置功能

hasText

：

对于Swift 2.3，我不得不将其作为一种方法而不是一种属性使用（因为它在文档中被引用）：

---

现在在swift 3/xcode 8中，文本属性是可选的，您可以这样做：

   @IBAction func Button(sender: AnyObject) {
       if textField1.text.utf16Count == 0 || textField2.text.utf16Count == 0 {

       }
    }

if ((textField.text ?? "").isEmpty) {
    // is empty
}

或：

或者，您可以进行如下扩展并使用它：

extension UITextField {
    var isEmpty: Bool {
        return text?.isEmpty ?? true
    }
}

...

if (textField.isEmpty) {
    // is empty
}

---

Swift 4.x解决方案

---

Swift 4/xcode 9

---

Swift 4.2

您可以为每个文本字段使用通用函数，只需在基本控制器中添加以下函数

// White space validation.
func checkTextFieldIsNotEmpty(text:String) -> Bool
{
    if (text.trimmingCharacters(in: .whitespaces).isEmpty)
    {
        return false

    }else{
        return true
    }
}

使用此扩展名

extension String {
    func isBlankOrEmpty() -> Bool {

      // Check empty string
      if self.isEmpty {
          return true
      }
      // Trim and check empty string
      return (self.trimmingCharacters(in: .whitespaces) == "")
   }
}

像这样

// Disable the Save button if the text field is empty.
let text = nameTextField.text ?? ""
saveButton.isEnabled = !text.isBlankOrEmpty()

---

---

textfield中有两个空格是什么？textfield中的空格：

如果let text=descriptionLabel.text，！text.trimmingCharacters（在：CharacterSet.whitespaces和newlines中）。我是空的{

来自Java，正在学习swift，“guard”似乎是atrocious@chrisl08为什么？有时候很好（例如，在验证链中，查看本页的第一个示例：）在Swift 2中不再工作，因为

text

属性是可选的。请检查下面的我的答案。

text属性

是可选的。在它之后添加：

if textField1.text！。isEmpty | textField2.text！。isEmpty

…请记住，如果该字段是必需的，用户可以输入空格，如果有必要，您应该检查此条件注意，我们已经收到报告说这在XCode 8中不起作用。你也可以尝试textField.text.isemptyth这已经在Swift 3

中更改为一个实例属性。hasText

问题是用户可以添加简单的空格。鉴于Swift应该简化事情，这似乎是苹果采取的一种不同的方式。Seri

text？.isEmpty？？true

是错误的。它只打开text属性，但结果（

true

）将永远不会被调用。正确的语法是

text？.isEmpty

或

text？.isEmpty==true

。我更喜欢后者，但在这种特殊情况下，text永远不会返回nil。您可以强制将其展开

返回text！。isEmpty

我会说

text？.isEmpty

和

text？.isEmpty==true

是不正确的，因为在这两种情况下，您都假设文本不能为零，这是错误的假设（请参阅UITextField中的Apple定义：

open var text:String？//默认值为零

）因此，苹果在这里实际上声明这可以是零。实际上，目前它不是零，但将来可能会改变，特别是如果苹果在其代码中添加了这样的注释。因此，如果文本为零，你应该将其视为文本字段为空。使用hasText属性可以，但它仅适用于iOS 10.0+如何回答这个问题@rollstuhlfahrer，谢谢！当我第一次给出答案时，我已经给出了最新Swift版本的答案。谢谢指出。希望这个答案有帮助。单行代码：

return（text.trimmingCharacters（in:.whitespaces.isEmpty）？false:true

为什么不直接返回

trimmingCharacters（in:.whitespaces.isEmpty）。isEmpty