UITextField 格式为 xx-xx-xxx

我正在使用 UITextField，我希望它应该采用 xx-xx-xxx 数字格式的字符。

有什么帮助吗？

需要对具有可变格式的电话号码很好地做到这一点，这就是我写的。随意重用 - 首先，我有一种过滤格式化字符串的方法，其中 # 是数字，任何其他字符都是某种“填充符”，应该在用户到达需要的位置后方便地插入。

NSMutableString *filteredPhoneStringFromStringWithFilter(NSString *string, NSString *filter)
{
    NSUInteger onOriginal = 0, onFilter = 0, onOutput = 0;
    char outputString[([filter length])];
    BOOL done = NO;

    while(onFilter < [filter length] && !done)
    {
        char filterChar = [filter characterAtIndex:onFilter];
        char originalChar = onOriginal >= string.length ? '\0' : [string characterAtIndex:onOriginal];
        switch (filterChar) {
            case '#':
                if(originalChar=='\0')
                {
                    // We have no more input numbers for the filter.  We're done.
                    done = YES;
                    break;
                }
                if(isdigit(originalChar))
                {
                    outputString[onOutput] = originalChar;
                    onOriginal++;
                    onFilter++;
                    onOutput++;
                }
                else
                {
                    onOriginal++;
                }
                break;
            default:
                // Any other character will automatically be inserted for the user as they type (spaces, - etc..) or deleted as they delete if there are more numbers to come.
                outputString[onOutput] = filterChar;
                onOutput++;
                onFilter++;
                if(originalChar == filterChar)
                    onOriginal++;
                break;
        }
    }
    outputString[onOutput] = '\0'; // Cap the output string
    return [NSString stringWithUTF8String:outputString];
}

现在，为了他们可以通过填充符删除，我修改了我应该更改范围内的字符。

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

    NSString *filter = @"(###) ### - ####";

    if(!filter) return YES; // No filter provided, allow anything

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

    if(range.length == 1 && // Only do for single deletes
       string.length < range.length &&
       [[textField.text substringWithRange:range] rangeOfCharacterFromSet:[NSCharacterSet characterSetWithCharactersInString:@"0123456789"]].location == NSNotFound)
    {
        // Something was deleted.  Delete past the previous number
        NSInteger location = changedString.length-1;
        if(location > 0)
        {
            for(; location > 0; location--)
            {
                if(isdigit([changedString characterAtIndex:location]))
                {
                    break;
                }
            }
            changedString = [changedString substringToIndex:location];
        }
    }

    textField.text = filteredPhoneStringFromStringWithFilter(changedString, filter);

    return NO;
}

这提供了一种非常干净的方法来强制用户以特定格式输入数字。