title: Angular4 <mat-progress-spinner> how to show and hide when a page load completes
body: <p>I am implementing a loading spinner to my application. From this site 
  <a href="https://material.angular.io/components/progress-spinner/overview" rel="nofollow noreferrer">https://material.angular.io/components/progress-spinner/overview</a>
  I could not able to get more info to show and hide.  I tried it out, but the spinner is always showing. Please help.</p>