title: not applicable WRITE_EXTERNAL_STORAGE
body: <p>I have a problem.
  I tried to read file system, but <code>directory.listFiles()</code> returns <code>null</code>
  I added <code>&lt;uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /&gt;</code> to Manifest, but problem remained.
  I added <code>int permissionCheck = ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE);</code> its return -1.</p>
  
  <p>I use android studio 2.2.2.
  AVD: Nexus 5 , API 25, Android 7.1.1 (Google APIs).
  Here you can get my project <a href="https://www.dropbox.com/s/bgn0esml47gfdb2/MyApplication22.7z?dl=0" rel="nofollow noreferrer">MyApplication22</a></p>