title: Android Oreo (API 26) - Create dir in external storage
body: <p>I've been developing an app on nougat that creates a directory in the external storage.</p>
  
  <p>I used to do it like this:</p>
  
  <pre><code>final File dir = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/Chords/Processed Audio");
  dir.mkdirs();
  </code></pre>
  
  <p>This code does not seem to work on API 26 (Android Oreo). The directory is not created.</p>
  
  <p><strong>How can I achieve the same thing, preferably that works on all android version from API 21 to API 26?</strong></p>