Intent ACTION_OPEN_DOCUMENT_TREE doesn't seem to return a real path to drive

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

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();

    }
}

However, the Uri looks something like /tree/... which doesn't seem to be a real path in the Android file system (verified via adb shell). How can I use this uri to query the contents of a portable storage device? I tried using the answer given here but the linked function returns null.