快速验证文本字段 3

Posted 2023-03-14

【中文标题】快速验证文本字段 3

【英文标题】：Validate text fields swift 3

【发布时间】：2016-12-07 16:56:25

【问题描述】：

我正在尝试使我的所有文本字段都成为必需的，以确保用户不会将其留空。我试过这个，但由于某种原因它不起作用。我觉得我的逻辑是正确的，但这是swift的逻辑问题

这是我的代码：

let title = txtTitle.text!
let location = txtWhere.text!
let when = txtWhen.text!


    if title != nil && location != nil && when != nil 

        var titleArray = [String]()
        var whereArray = [String]()
        var whenArray = [String]()

        let titleObject = UserDefaults.standard.object(forKey: "saveTitle")
        let whereObject = UserDefaults.standard.object(forKey: "saveLocation")
        let whenObject = UserDefaults.standard.object(forKey: "saveWhen")




        if let tempTitle = titleObject as? [String] 

            titleArray = tempTitle
            titleArray.append(txtTitle.text!)
            print(titleArray)

        
        else 

            titleArray = [txtTitle.text!]

        

        if let tempWhere = whereObject as? [String] 

            whereArray = tempWhere
            whereArray.append(txtWhere.text!)
            //print(titleArray)

        
        else 

            whereArray = [txtWhere.text!]

        

        if let tempWhen = whenObject as? [String] 

            whenArray = tempWhen
            whenArray.append(txtWhen.text!)
            //print(titleArray)

        
        else 

            whenArray = [txtWhen.text!]

        


        UserDefaults.standard.set(titleArray, forKey: "saveTitle")
        UserDefaults.standard.set(whereArray, forKey: "saveLocation")
        UserDefaults.standard.set(whenArray, forKey: "saveWhen")
        txtTitle.text = ""
        txtWhere.text = ""
        txtWhen.text = ""
        txtTime.text = ""

    
        else
    

        errMsg.isHidden = false
        errMsg.text = "All fields are required"

    

【问题讨论】：

试试这个，例如txtTitle.text?.characters.count > 0。请重构您的代码..注意强制解包选项！

@ThomasG.，如果您使用SwiftLint，它将不鼓励将count 与0 进行比较，并推荐isEmpty。 ;)

【参考方案1】：

为了可靠地检查文本字段的text 属性是否不是nil 并且不是空的使用

if let title = txtTitle.text, !title.isEmpty,
   let location = txtWhere.text, !location.isEmpty,
   let when = txtWhen.text, !when.isEmpty  ...

如果所有条件都通过，则三个变量被安全地解包。

【参考方案2】：

一个。您不应该强制展开 (txtTitle.text!)：而是检查可选值

b.您可能想要检查空字符串，而不仅仅是 nil

也就是说，您可以这样测试有效性：

let title = txtTitle.text
if title?.isEmpty == false 
    ...// title was filled

或者更好（谢谢 Leo Dabus）：

if let title = txtTitle.text, !title.isEmpty 
    ...// title was filled

【讨论】：

if let title = txtTitle.text, !title.isEmpty

【参考方案3】：

文本字段验证 ======================>

func textFieldShouldReturn(_ textField: UITextField) -> Bool

    switch (textField.tag)
    
    case 1:

        password.becomeFirstResponder()

    case 2 :

        confirm_pass.becomeFirstResponder()

    case 3 :

        email.becomeFirstResponder()

    case 4 :

        phone.becomeFirstResponder()

    case 5 :

        phone.resignFirstResponder()

    default: break
    
    return true



func textFieldShouldClear(_ textField: UITextField) -> Bool

    return true



func textFieldDidEndEditing(_ textField: UITextField)

    if (textField == username)
    
        let name_reg = "[A-Za-z0-9]5,20"

        let name_test = NSPredicate(format: "SELF MATCHES %@", name_reg)

        if name_test.evaluate(with: username.text) == false
        
            let alert = UIAlertController(title: "Information", message: "Enter the name in correct format", preferredStyle: .alert)
            let ok = UIAlertAction(title: "Ok", style: .default, handler: nil)
            let cancel = UIAlertAction(title: "Cancel", style: .default, handler: nil)

            alert.addAction(ok)
            alert.addAction(cancel)

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

    if (textField == password)
    
        let name_reg = "[A-Z0-9a-z._%@+-]6,10"

        let name_test = NSPredicate(format: "SELF MATCHES %@", name_reg)

        if name_test.evaluate(with: password.text) == false
        
            let alert = UIAlertController(title: "Information", message: "Enter the password in correct format", preferredStyle: .alert)
            let ok = UIAlertAction(title: "Ok", style: .default, handler: nil)
            let cancel = UIAlertAction(title: "Cancel", style: .default, handler: nil)

            alert.addAction(ok)
            alert.addAction(cancel)

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

    if (textField == email)
    
        let name_reg = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]2,"

        let name_test = NSPredicate(format: "SELF MATCHES %@", name_reg)

        if name_test.evaluate(with: email.text) == false
        
            let alert = UIAlertController(title: "Information", message: "Enter the E-mail in correct format", preferredStyle: .alert)
            let ok = UIAlertAction(title: "Ok", style: .default, handler: nil)
            let cancel = UIAlertAction(title: "Cancel", style: .default, handler: nil)

            alert.addAction(ok)
            alert.addAction(cancel)

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

    if (textField == phone)
    
        let name_reg = "[0-9]10"

        let name_test = NSPredicate(format: "SELF MATCHES %@", name_reg)

        if name_test.evaluate(with: phone.text) == false
        
            let alert = UIAlertController(title: "Information", message: "Enter your number in correct format", preferredStyle: .alert)
            let ok = UIAlertAction(title: "Ok", style: .default, handler: nil)
            let cancel = UIAlertAction(title: "Cancel", style: .default, handler: nil)

            alert.addAction(ok)
            alert.addAction(cancel)

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

【讨论】：

欢迎来到 ***。虽然这个答案可能是正确的，但从长远来看，留下一些解释会改善这个问题。