Question

我想验证我的UITextfield小于2的字符数，只输入数字... seen this

Answer 1

试试这个...

#define NUMBERS_ONLY @"1234567890"
#define CHARACTER_LIMIT 2

并以此方法----

 - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string  {
        NSUInteger newLength = [textField.text length] + [string length] - range.length;
        NSCharacterSet *cs = [[NSCharacterSet characterSetWithCharactersInString:NUMBERS_ONLY] invertedSet];
        NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""];
        return (([string isEqualToString:filtered])&&(newLength <= CHARACTER_LIMIT));
    }

Answer 2

这有效!!

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string 
{
if ([string isEqualToString:@""]) return YES;
unichar c = [string characterAtIndex:0];
    if ([[NSCharacterSet decimalDigitCharacterSet] characterIsMember:c])
    {
        int maxVal = 2;
        if (textField.text.length >= maxVal)
            return NO;
        else
            return YES;
    } else {
        return NO;
    }
}

Answer 3

在iOS中处理此问题的标准方法是将UITextFieldDelegate附加到UITextField，并实施textField:shouldChangeCharactersInRange:replacementString:方法。在此方法中，您可以验证字符串

使用属性length来实现此目的

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
    if([textField.text length]<2)
        return YES;
    else
        return NO;
}

Answer 4

尝试这样，

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
    if([textField.text length]<2)
        return YES;
    else
        return NO;
}

并将NSNumberkeyboard类型指定给文本字段。

Answer 5

使用所有字母声明NSCharaterSet的另一种方法，并检查字段的文本是否包含任何字母：

NSCharacterSet *alphabet = [NSCharacterSet characterSetWithCharactersInString:@"abcdefghijklmnopqrstuvwxyz"]
if ([[self.label.text lowercaseString] rangeOfCharacterFromSet:alphabet].location != NSNotFound) 
{
     NSLog(@"Found letters!");
}

如何验证UITextfield，使其只包含数字，不包含小于2的os字符

5 个答案: