title: Couldn't append the text onto a Google Drive File
body: <p>I am trying to append text to a text file on the Google Drive. But when I write, it whole file is overwritten. Why can't I just add the text in the end of the file?</p>
  
  <pre><code>  DriveFile file = Drive.DriveApi.getFile(mGoogleApiClient, id);
    file.open(mGoogleApiClient, DriveFile.MODE_WRITE_ONLY, null).setResultCallback(new ResultCallback&lt;DriveApi.DriveContentsResult&gt;() {
          @Override
            public void onResult(DriveApi.DriveContentsResult driveContentsResult) {
                    msg.Log("ContentsOpenedCallBack");
  
                    if (!driveContentsResult.getStatus().isSuccess()) {
                       Log.i("Tag", "On Connected Error");
                       return;
                    }
  
                    final DriveContents driveContents = driveContentsResult.getDriveContents();
  
                    try {
                       msg.Log("onWrite");
                       OutputStream outputStream = driveContents.getOutputStream();
                       Writer writer = new OutputStreamWriter(outputStream);
                       writer.append(et.getText().toString());
                       writer.close();
                       driveContents.commit(mGoogleApiClient, null);
  
                    } catch (IOException e) {
                       e.printStackTrace();
                    }
               }
  
   });
  </code></pre>