iOS中UITextField的验证[重复]答案

【问题标题】：Validation on UITextField in iOS [duplicate]iOS中UITextField的验证[重复]
【发布时间】：2014-02-10 06:39:28
【问题描述】：

我创建了一个UITextField，并且我想对 textfield(userName) 进行验证，以便只允许使用字符。如果用户输入了数字或特殊字符等字母以外的任何其他内容，则不应出现，并且应该有显示相同内容的通知。

【问题讨论】：

标签： ios iphone objective-c uitextfield

【解决方案1】：

#define ALPHA @"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{


    NSCharacterSet *blockedCharacters = [[NSCharacterSet characterSetWithCharactersInString:ALPHA] invertedSet];

    if (!([string rangeOfCharacterFromSet:blockedCharacters].location == NSNotFound)) {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Message" message:@"Only allow alphabet." delegate:self cancelButtonTitle:@"Okay" otherButtonTitles:nil, nil];
        [alert show];
    }

    return ([string rangeOfCharacterFromSet:blockedCharacters].location == NSNotFound);

}

【讨论】：

【解决方案2】：

你可以试试这个：

    -(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
    {
        if(textField==YOUR_TEXTFIELD_NAME)
        {
            NSCharacterSet *myCharSet = [NSCharacterSet characterSetWithCharactersInString:@"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"];
            for (int i = 0; i < [string length]; i++) {
                unichar c = [string characterAtIndex:i];
                if (![myCharSet characterIsMember:c]) {
                    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error" message:@"Numbers not allowed" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
                    [alert show];
                    return NO;
                }

            }

    }
return YES;
}

确保为文本字段设置委托。

【讨论】：

感谢重播，但此代码也允许
1.您是否将 UITextField 与 IBOutlet 连接？ 2. 您是否将 UITextFieldDelegate 设置为您的文本字段？
先生，downvoter.. 想解释一下为什么不赞成？ ://

【解决方案3】：

try this 

NSCharacterSet *blockedCharacters = [[NSCharacterSet alphanumericCharacterSet] invertedSet];

- (BOOL)textField:(UITextField *)field shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)characters
{
    return ([characters rangeOfCharacterFromSet:blockedCharacters].location == NSNotFound);
}

【讨论】：

【解决方案4】：

#define ACCEPTABLE_NUMBER @"1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{

        NSCharacterSet *acceptedInput = [[NSCharacterSet characterSetWithCharactersInString:ACCEPTABLE_NUMBER]invertedSet];
        NSString *filtered = [[string componentsSeparatedByCharactersInSet:acceptedInput] componentsJoinedByString:@""];
        if ((![filtered isEqualToString:string]))
            return NO;
    }

}

【讨论】：