title: Android - How to execute main functionality of project only by clicking on the icon of application?
body: <p>I am making an app and required to execute its main functionality only by clicking on its icon.</p>
  
  <p>In other words no layout no widget just its working.</p>
  
  <p>As soon as user click on the icon it should execute its main functionality. One way I think of is to put all the code in <code>onCreate</code> function.</p>
  
  <p>Or if there is any other way please share with me.</p>