title: how to make service running even if activity closed?
body: <p>I have an application that communicates with socket.</p>
  
  <p>I want bind <strong>socket service</strong> to the communication activity. But if the <strong>activity closed</strong>, the <strong>service destoryed</strong>. </p>
  
  <p>How can I keep the socket service running whatever the activity is open or closed?</p>
  
  <p>If I started notification to my application when the activity stopped, the service is running or not?</p>