title: Android: make a folder on external memory private or protected
body: <p>I want to make a folder on the external memory (could be on SD card) private or protected so that only my application/process can have access to that folder.</p>
  
  <p>Can I do this? if so please let me know?</p>
  
  <p>my requirement:
  I can use android's internal memory to store my app's files/data, but that may decrease the phone's internal memory (that can cause problems like not having enough space for other apps to install, etc)</p>