ios - Swift : textField可输入的长度为4个汉字或者8个字符。咋判断

Question

        if self.tf.text?.characters.count > 4 {
            Tool.alertUser("昵称最多4个汉字，或者8个字符；数字，字母占一个字符，汉字占2个字符")
            return
        }

汉字最多4个，但是有人用英文名，只有4个字母明显不够，这咋办？

Answer 1

var length = 0
for char in nickNameTF.text!.characters {
    // 判断是否中文，是中文+2 ，不是+1
    length += "\(char)".lengthOfBytesUsingEncoding(NSUTF8StringEncoding) == 3 ? 2 : 1
}
if length > 8 {
    Tool.alertUser("字数限制为4个汉字或者8个字符；汉字算2个字符，字母、数字算1个字符")
    return
}

Answer 2

• First of all, a Chinese character does not necessarily occupy 2 bytes.

• Secondly, you can try to control the length through String().utf8.count.

• Finally, you can also control it through regular expressions.

Answer 3

I have seen many input boxes that are counted in bytes.

Answer 4

I feel that the problem of the question should be solved like this. Although Chinese characters may occupy 3 characters, we "think" it is two characters. The purpose is to control the length of Chinese and English nicknames, not for the length of utf8
So we should judge if ( a > ; 0x4e00 && a < 0x9fff){Then it’s Chinese, counting two characters}
But it’s not so laborious at the moment, just limit it to a unified value, for example, 10 is good