如何制作一个将需要的文本字段 4 数字或数字 iphone

示例代码

:

- /BOOL/textField:/UITextField */textField shouldChangeCharactersInRange:/NSRange/range replacementString:/NSString */string

{

 NSString *currentString = [textField.text stringByReplacingCharactersInRange:range withString:string];

 int length = [currentString length];

 if /length > 4/ {

 return NO;

 }

 return YES;

}

Swift 3.0 Xcode 8.3.3.

..

第一的

UITextField

安装委托，然后放置此代码...

func textField/_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String/ -> Bool {

 let textstring = /textField.text! as NSString/.replacingCharacters/in: range, with: string/

 let length = textstring.characters.count

 if length > 4 {

 return false

 }

 return true

}

Objective C 代码。

..

- /BOOL/textField:/UITextField */textField shouldChangeCharactersInRange:/NSRange/range replacementString:/NSString */string

 {

 NSString *textstring = [textField.text stringByReplacingCharactersInRange:range withString:string];

 int length = [textstring length];

 if /length > 4/ {

 return NO;

 }

 return YES;

 }

下面的代码帮助我建立了仅限的限制 2 图I. 4 文本字段中的数字作为输入数据。 进入两位数焦点后，会自动转到下一个文本字段。

https://i.stack.imgur.com/CCEiG.png

override func viewDidLoad// {

 super.viewDidLoad//



 // Set an action on EditingChanged event of textfield

 txtCardDetails3.addTarget/self, action: #selector/VerifyCardViewController.textFieldDidChange/_://, forControlEvents: UIControlEvents.EditingChanged/

}



func textFieldDidChange/textField: UITextField/{



 let text = textField.text



 if textField.tag == 101 { // Set tag to textfield /if multiple/ during design time

 if text?.utf16.count==2 {

 txtCardDetails4.becomeFirstResponder// // Move to next text field

 }

 }

}



func textFieldDidBeginEditing/textField: UITextField/ {

 textField.becomeFirstResponder//

}



func textFieldShouldReturn/textField: UITextField/ -> Bool {

 textField.resignFirstResponder//

 return true;

}





//User can enter two digits in textfield with tag 101 and four digits in textfield with tag 102

 func textField/textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String/ -> Bool {

 if let text = textField.text {



 let newStr = /text as NSString/

 .stringByReplacingCharactersInRange/range, withString: string/

 if newStr.isEmpty {

 return true

 }

 let intvalue = Int/newStr/



 if textField.tag == 101 { print/"101"/

 return /intvalue >= 0 && intvalue <= 99/ ? true : false

 }

 else if textField.tag == 102 { print/"102"/

 return /intvalue >= 0 && intvalue <= 9999/ ? true : false

 }



 }

 return true

 }

编辑

:

首先改变你的 textFiled keyBoard 一种

UIKeyboardTypeNumberPad

, 仅限您的键盘 numeric/digit.

并给予

标签

你的他

UITextField

, 你想要申请

/只输入4位数字/

, 例如

textField.tag = 101; /// this is for, if you have multiple textFiled then it recognize that which textFiled have limit of 4 number ;

并使用以下代码方法：

- /BOOL/textField:/UITextField */textField shouldChangeCharactersInRange:/NSRange/range replacementString:/NSString */string

{

 if/textField.tag != 101/

 return YES;



 if/string.length == 0/

 return YES;



 if/textField.text.length == 4/

 return NO;



 NSCharacterSet *nonNumberSet = [[NSCharacterSet decimalDigitCharacterSet] invertedSet];



 if /[string rangeOfCharacterFromSet:nonNumberSet].location != NSNotFound/

 {

 return NO;

 }

 return YES;

}