Textfield.text 输入的内容应具有特定格式

Question

我有一个 textfield，我希望以以下格式在其中输入文本： AA #### 1234 我知道这应该在 shouldChangeCharactersInRange delegate 方法中完成 textfield.nut 我无法理解如何在每个 [=18= 上实现条件] 提前给你suggestions.Thanks！

Answer 1

在 UITextField 上创建类别，并根据您的要求添加此方法写入条件。下面是电子邮件 ID 的示例：

 - (BOOL)validateRegEx:(NSString*)regexString
 {
     NSError *error = NULL;
     NSRegularExpression *regex = [NSRegularExpression    regularExpressionWithPattern:regexString
                                                                      options:NSRegularExpressionCaseInsensitive
                                                                         error:&error];
     NSUInteger numberOfMatches = [regex numberOfMatchesInString:self.text
                                                    options:0
                                                      range:NSMakeRange(0, [self.text length])];

    return numberOfMatches > 0;
}

Answer 2

试试这个

-(BOOL)checkString:(NSString *)str{
    NSString *regex1 = @"^[a-bA-B0-9]"; // chabge regex as per your needs
    NSPredicate *test1 = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex1];
    return [test1 evaluateWithObject:str] ;
}

Answer 3

有助于验证您的需求的表达式可能是：

^[a-z]{2}\s\d{4}\s\d{4}$

这里：

^ - Shows start of string

[a-z]{2} - Shows any character between a-z exactly 2 times

\s - Shows white space character one time.

\d{4} - Shows any digit from 0-9, exactly 4 times.

$ - Shows end of string

一个解决方法的例子可能是这个，这里棘手的部分是允许正在构建的字符串：

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    NSError *error = NULL;
    NSRegularExpression *regex = nil;

     NSMutableString *combinedText = [textField.text mutableCopy];
    [combinedText replaceCharactersInRange:range withString:string];

    switch (combinedText.length) {
        case 1:
        case 2:
            regex = [NSRegularExpression regularExpressionWithPattern:[NSString stringWithFormat:@"^[a-z]{%ld}", (long)combinedText.length] options:NSRegularExpressionCaseInsensitive error:&error];
            break;
        case 3:
            regex = [NSRegularExpression regularExpressionWithPattern:@"^[a-z]{2}\s" options:NSRegularExpressionCaseInsensitive error:&error];
            break;
        case 4:
        case 5:
        case 6:
        case 7:
            regex = [NSRegularExpression regularExpressionWithPattern:[NSString stringWithFormat:@"^[a-z]{2}\s\d{%ld}", (long)combinedText.length - 3] options:NSRegularExpressionCaseInsensitive error:&error];
            break;
        case 8:
            regex = [NSRegularExpression regularExpressionWithPattern:@"^[a-z]{2}\s\d{4}\s" options:NSRegularExpressionCaseInsensitive error:&error];
            break;
        case 9:
        case 10:
        case 11:
        case 12:
            regex = [NSRegularExpression regularExpressionWithPattern:[NSString stringWithFormat:@"^[a-z]{2}\s\d{4}\s\d{%ld}$", (long)combinedText.length - 8] options:NSRegularExpressionCaseInsensitive error:&error];
            break;
        default:
            return false;
    }

    if(error) return false;        

    NSUInteger numberOfMatches = [regex numberOfMatchesInString:combinedText options:0 range:NSMakeRange(0, combinedText.length)];
    return numberOfMatches > 0 || string.length == 0;
}

希望对您有所帮助！

Textfield.text 输入的内容应具有特定格式

Textfield.text entered should have a specific format

objective-c

ios

uitextfielddelegate