UITextField 对输入字符的限制

• 判断时候含特殊符号
  第一种：

[ \~\!\/\@\#\$\%\^\&#\$\%\\&\\(\)\-\_\=\+\\\|\[\{\}\]\;\:\'\"\,\&#\$\%\^\&\\(\)\-\\=\+\\\|\[\{\}\]\;\:\'\"\,\<\.\&#\$\%\^\&\*\(\)\-\\=\+\\\|\[\{\}\]\;\:\'\"\,\<\.\>\/\?]

实用方法：

NSString * nameCharacters =@"[ \\~\\!\\/\\@\\#\\$\\%\\^\\&#\\$\\%\\^\\&\\*\\(\\)\\-\\_\\=\\+\\\\\\|\\[\\{\\}\\]\\;\\:\\\'\\\"\\,\\&#\\$\\%\\^\\&\\*\\(\\)\\-\\_\\=\\+\\\\\\|\\[\\{\\}\\]\\;\\:\\\'\\\"\\,\\<\\.\\&#\\$\\%\\^\\&\\*\\(\\)\\-\\_\\=\\+\\\\\\|\\[\\{\\}\\]\\;\\:\\\'\\\"\\,\\<\\.\\>\\/\\?]";

• 判读是否含表情符号

• (BOOL)stringContainsEmoji:(NSString *)string
  {
  __block BOOL returnValue = NO;
  [string enumerateSubstringsInRange:NSMakeRange(0, [string length])
  options:NSStringEnumerationByComposedCharacterSequences
  usingBlock:^(NSString * _Nullable substring, NSRange substringRange, NSRange enclosingRange, BOOL * _Nonnull stop) {
  const unichar hs = [substring characterAtIndex:0];
  // surrogate pair
  if (0xd800 <= hs && hs <= 0xdbff)
  {
  if (substring.length > 1)
  {
  const unichar ls = [substring characterAtIndex:1];
  const int uc = ((hs - 0xd800) * 0x400) + (ls - 0xdc00) + 0x10000;
  if (0x1d000 <= uc && uc <= 0x1f918)
  {
  returnValue = YES;
  }
  }
  }
  else if (substring.length > 1)
  {
  const unichar ls = [substring characterAtIndex:1];
  if (ls == 0x20e3 || ls == 0xFE0F || ls == 0xd83c)
  {
  returnValue = YES;
  }
  }
  else
  {
  // non surrogate
  if (0x2100 <= hs && hs <= 0x27ff)
  {
  if (0x278b <= hs && 0x2792 >= hs)
  {
  returnValue = NO;
  }
  else
  {
  returnValue = YES;
  }
  }
  else if (0x2B05 <= hs && hs <= 0x2b07)
  {
  returnValue = YES;
  }
  else if (0x2934 <= hs && hs <= 0x2935)
  {
  returnValue = YES;
  }
  else if (0x3297 <= hs && hs <= 0x3299)
  {
  returnValue = YES;
  }
  else if (hs == 0xa9 || hs == 0xae || hs == 0x303d || hs == 0x3030 || hs == 0x2b55 || hs == 0x2b1c || hs == 0x2b1b || hs == 0x2b50 || hs == 0xd83e)
  {
  returnValue = YES;
  }
  }
  }];
  return returnValue;
  }

  NSPredicate * isSpecialCharacter = [NSPredicatepredicateWithFormat:@"SELF MATCHES%@",nameCharacters];

[isSpecialCharacterevaluateWithObject:applicantName]
返回YES存在特殊字符。
第二种：

[~!/@#$%^&#$%&()-_=+\|[{}];:'",&#$%^&()-=+\|[{}];:'",<.&#$%^&*()-=+\|[{}];:'",<.>/?]+