title: Why cannot use special character(over 10000 unicode ) file name in SD card?
body: <p>Recently I got a trouble to copy a file to removable SD card from internal SD card in Android.</p>
  
  <p>This file has a special character "snake"(<a href="http://www.fileformat.info/info/unicode/char/1f40d/index.htm" rel="nofollow">http://www.fileformat.info/info/unicode/char/1f40d/index.htm</a>).</p>
  
  <p>It can save to internal SD card.
  But it cannot copy to removable SD card.
  I tried to copy to removable SD card from my PC. 
  But it was failed, too.</p>
  
  <p>So that I have created a code to change special character to something.</p>
  
  <pre><code>for(int i =0; i &lt; input.length(); i++) {
          if(input.codePointAt(i) &gt; 0xFFFF) { //check is it special character?
              //change string!!!!! 
              i ++;
          } else {
              builder.append(input.charAt(i));
          }
      }
  </code></pre>
  
  <p>It worked so that i could resolve my problem. 
  But I want to know the reason of </p>
  
  <p><strong>why I cannot copy to removable SD card which has a special character(unicode 10000 over like U+1f40d).</strong></p>