title: Intent ACTION_OPEN_DOCUMENT_TREE doesn't seem to return a real path to drive
body: <p>I'm trying to read files from a USB storage device connected to my Google Pixel. I'm currently using this method to select the path of the drive so I can query it for its contents</p>
  
  <pre><code>private static final String TAG = "MainActivity";
  private static final int REQUEST_CHOOSE_DRIVE = 1;
  private TextView tv;
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
  
      tv = (TextView) findViewById(R.id.text);
  
      Intent i = new Intent(Intent.ACTION_OPEN_DOCUMENT_TREE);
  
      startActivityForResult(i, REQUEST_CHOOSE_DRIVE);
  }
  
  @Override
  protected void onActivityResult(int requestCode, int resultCode, Intent data) {
      if (requestCode == REQUEST_CHOOSE_DRIVE) {
  
          Uri uri = data.getData();
  
      }
  }
  </code></pre>
  
  <p>However, the Uri looks something like <code>/tree/...</code> which doesn't seem to be a real path in the Android file system (verified via <code>adb shell</code>). How can I use this <code>uri</code> to query the contents of a portable storage device? I tried using the answer given <a href="https://stackoverflow.com/questions/29713587/howto-get-the-real-path-with-action-open-document-tree-intent-lollipop-api-21">here</a> but the linked function returns <code>null</code>.</p>