title: Retrieve all video files from all directories of SD card
body: <p>I'm making a media player. I want to get all videos present in the <strong>sd card</strong>.</p>
  
  <p>If the video is directly available in top directory of <strong>sd card</strong>, it is simple. But what about a video file exists in nested directory structure like </p>
  
  <blockquote>
    <p>directory->directory->directory->file.mp4.</p>
  </blockquote>
  
  <p>How can I search for a file in a nested directory structure?</p>