只允许UITextField的字母数字字符

我将如何去允许在iOS UITextField只input字母数字字符？

Answer 1

使用UITextFieldDelegate方法-textField:shouldChangeCharactersInRange:replacementString:使用NSCharacterSet包含要允许的字符的反转。 例如：

 // in -init, -initWithNibName:bundle:, or similar NSCharacterSet *blockedCharacters = [[[NSCharacterSet alphanumericCharacterSet] invertedSet] retain]; - (BOOL)textField:(UITextField *)field shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)characters { return ([characters rangeOfCharacterFromSet:blockedCharacters].location == NSNotFound); } // in -dealloc [blockedCharacters release]; 

请注意，您将需要声明您的类实现协议（即@interface MyClass : SomeSuperclass <UITextFieldDelegate> ），并将文本字段的delegate设置为您的类的实例。

Answer 2

这是我如何做到的：

 // Define some constants: #define ALPHA @"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" #define NUMERIC @"1234567890" #define ALPHA_NUMERIC ALPHA NUMERIC // Make sure you are the text fields 'delegate', then this will get called before text gets changed. - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string { // This will be the character set of characters I do not want in my text field. Then if the replacement string contains any of the characters, return NO so that the text does not change. NSCharacterSet *unacceptedInput = nil; // I have 4 types of textFields in my view, each one needs to deny a specific set of characters: if (textField == emailField) { // Validating an email address doesnt work 100% yet, but I am working on it.... The rest work great! if ([[textField.text componentsSeparatedByString:@"@"] count] > 1) { unacceptedInput = [[NSCharacterSet characterSetWithCharactersInString:[ALPHA_NUMERIC stringByAppendingString:@".-"]] invertedSet]; } else { unacceptedInput = [[NSCharacterSet characterSetWithCharactersInString:[ALPHA_NUMERIC stringByAppendingString:@".!#$%&'*+-/=?^_`{|}~@"]] invertedSet]; } } else if (textField == phoneField) { unacceptedInput = [[NSCharacterSet characterSetWithCharactersInString:NUMERIC] invertedSet]; } else if (textField == fNameField || textField == lNameField) { unacceptedInput = [[NSCharacterSet characterSetWithCharactersInString:ALPHA] invertedSet]; } else { unacceptedInput = [[NSCharacterSet illegalCharacterSet] invertedSet]; } // If there are any characters that I do not want in the text field, return NO. return ([[string componentsSeparatedByCharactersInSet:unacceptedInput] count] <= 1); } 

也请查看UITextFieldDelegate参考 。

Answer 3

我发现一个简单而有效的答案，并希望分享：

将事件EditingChanged的UITextField连接到以下的IBAction

 -(IBAction) editingChanged:(UITextField*)sender { if (sender == yourTextField) { // allow only alphanumeric chars NSString* newStr = [sender.text stringByTrimmingCharactersInSet:[[NSCharacterSet alphanumericCharacterSet] invertedSet]]; if ([newStr length] < [sender.text length]) { sender.text = newStr; } } } 

Answer 4

Swift 3版本

目前接受的答案方法：

 func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool { // Get invalid characters let invalidChars = NSCharacterSet.alphanumerics.inverted // Attempt to find the range of invalid characters in the input string. This returns an optional. let range = string.rangeOfCharacter(from: invalidChars) if range != nil { // We have found an invalid character, don't allow the change return false } else { // No invalid character, allow the change return true } } 

另一个同样function的方法

 func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool { // Get invalid characters let invalidChars = NSCharacterSet.alphanumerics.inverted // Make new string with invalid characters trimmed let newString = string.trimmingCharacters(in: invalidChars) if newString.characters.count < string.characters.count { // If there are less characters than we started with after trimming // this means there was an invalid character in the input. // Don't let the change go through return false } else { // Otherwise let the change go through return true } } 

Answer 5

对于Swift：将事件EditingChanged的UITextField连接到以下的IBAction：

 @IBAction func ActionChangeTextPassport(sender:UITextField){ if sender == txtPassportNum{ let newStr = sender.text?.stringByTrimmingCharactersInSet(NSCharacterSet.alphanumericCharacterSet().invertedSet) if newStr?.characters.count < sender.text?.characters.count{ sender.text = newStr } } } 

Answer 6

您将不得不使用textField delegate方法，并使用textFieldDidBeginEditing ， shouldChangeCharactersInRange和textFieldDidEndEditing方法检查字符。

请参阅此链接的文档。

Answer 7

Swift中的RegEx方法：

 func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool { if string.isEmpty { return true } let alphaNumericRegEx = "[a-zA-Z0-9]" let predicate = NSPredicate(format:"SELF MATCHES %@", alphaNumericRegEx) return predicate.evaluate(with: string) }