title: Python Kivy: Search directory for filetype
body: <p>There are many ways, to search a dir for containing a string, that's not really my question. But is there something built in for Python Kivy, that allows automatically searching for files (*.mp3) in a directory with subdirs, or do I have to create one on my own?
  If I have to do so, how do I get all the files and subdirs in a directory?</p>
  
  <p>Thank you :)</p>
  
  <p><strong>Finally I decided coding the needed function on my own:</strong></p>
  
  <pre><code>import os
  def listfiles(path):
       files = []
       for base, directory, filename in os.walk(path):
            for i in range(len(filename)):
                 files.append(base+"/"+filename[i])
       return files
  print(listfiles("/path/path/"))
  </code></pre>
  
  <p>Checking files for extensions should be easy enaugh :)</p>
  
  <p><strong><em>Unfortunately the process might take very long for bigger directories, so I'm still looking for a different solution.</em></strong></p>