UITextField限制字符的数量和类型

Question

我有两个文本字段,我想限制字符的数量和类型.我已经使用以下代码来单独执行每个功能,但无法在同一个函数中找到两种方法.

要限制字符的类型:

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    // Only characters in the NSCharacterSet you choose will insertable.
    NSCharacterSet *invalidCharSet = [[NSCharacterSet characterSetWithCharactersInString:@"abcdefgABCDEFG"] invertedSet];
    NSString *filtered = [[string componentsSeparatedByCharactersInSet:invalidCharSet] componentsJoinedByString:@""];
    return [string isEqualToString:filtered];
}

并限制字符数:

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
 if (textField.text.length >= 10 && range.length == 0)
 return NO;
return YES;
}

Answer 1

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    if (textField.text.length >= 10 && range.length == 0)
       return NO;
    // Only characters in the NSCharacterSet you choose will insertable.
    NSCharacterSet *invalidCharSet = [[NSCharacterSet characterSetWithCharactersInString:@"abcdefgABCDEFG"] invertedSet];
    NSString *filtered = [[string componentsSeparatedByCharactersInSet:invalidCharSet] componentsJoinedByString:@""];
    return [string isEqualToString:filtered];
}

编辑

如果你想为第三个文本字段添加不同的条件,那么你可以这样做.
为第三个文本fild创建引用说thirdField

然后用这个

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    if (textField == thirdField) {
        //your contion e.g
        if (textField.text.length < 7) {
            return YES;
        } else {
            return NO;
        }        
    }
    else {
        if (textField.text.length >= 10 && range.length == 0)
            return NO;
        // Only characters in the NSCharacterSet you choose will insertable.
        NSCharacterSet *invalidCharSet = [[NSCharacterSet characterSetWithCharactersInString:@"abcdefgABCDEFG"] invertedSet];
        NSString *filtered = [[string componentsSeparatedByCharactersInSet:invalidCharSet] componentsJoinedByString:@""];
        return [string isEqualToString:filtered];
    }
}