title: Countdown for Zxing barcode library
body: <p>I start the scan in my app with intents like this:</p>
  
  <pre><code>Intent intent = new Intent("com.google.zxing.client.android.SCAN");
  intent.setPackage("com.google.zxing.client.android");
  </code></pre>
  
  <p>It works well, but if the scanning can't find any match with the image, how can I add a countdown to finish the scanning?</p>