code: private void init() {
          curDirectory = new File(Environment.getExternalStorageDirectory().getPath());
          currentFile = new File(curDirectory.getPath());
          lastDirectory = curDirectory.getParentFile();
  
          if (curDirectory.isDirectory()) {
              new UpdateFilesTask(this).execute(curDirectory);
          } else {
              try {
                  throw new Exception(getString(R.string.file_picker_directory_error));
              } catch (Exception e) {
                  e.printStackTrace();
              }
          }
      }
docs: Initialize the current directory.