title: How can I detect if there is physical headphone jack in Android?
body: <p>I thought there is always a headphone jack in Android phone.</p>
  
  <p>However, few days ago, I found that there is no headphone jack to plugin my headphone on OPPO R8106.</p>
  
  <p>Is there any way to detect if there is headphone jack existing on Android?</p>
  
  <p>My workaround solution is to register a <code>BroadcastReceiver</code> , if BroadcastReceiver receive a message in 5 second, I would thing there is a headphonce jack in this phone.</p>
  
  <p>Any convenient way existing?</p>