//判断输入文本中字符串的长度
 
if ([self convertToInt:chooseRollTextField.text] > 20) {
    [self showToast:@"输入的角色名不能超过20个汉字或40个字符哦!"];
    return;
}
 
-  (int)convertToInt:(NSString*)strtemp {
    int strlength = 0;
    char* p = (char*)[strtemp cStringUsingEncoding:NSUnicodeStringEncoding];
    for (int i=0 ; i<[strtemp lengthOfBytesUsingEncoding:NSUnicodeStringEncoding] ;i++) {
        if (*p) {
            p++;
            strlength++;
        }
        else {
            p++;
        }
    }
     
    int result = (strlength+1)/2;
    return result;
}