title: Installing third party APK from another App
body: <p>Currently I'm developing an app and I included an <code>apk</code> that created by third party to be installed on specific condition. This <code>apk</code> is stored on <code>assets</code> folder. The problem is when I tried to install the third party apk, it ask me to activate allow the unknown source setting.</p>
  
  <p>My questions are,</p>
  
  <ol>
  <li>Can an <code>.apk</code> file contain another third party <code>.apk</code> file in its assets directory while uploading to Google Play?</li>
  <li>Is it possible to sign a third party apk (make it known source)? So it won't prompt the user to allow the setting.</li>
  </ol>