title: Show/Hide a group of polyline in Google Map Android API V2
body: <p>I'm doing a simple project that can trace user's positions and plot these locations using <code>Polyline</code>. Now I want to add a check box to toggle whether to display these lines or not. The challenge I think is that I have many polylines here so I don't know how to set all of them invisible/visible at the same time.</p>
  
  <p>Maybe I can draw them on a layer then toggle visibility of that layer? I'm just guessing..</p>
  
  <p>Does anyone know how to do it?  Thanks in advance :)</p>
  
  <p>EDIT:
  Probably not very related but I'll still show how I add polyline once detect user move</p>
  
  <pre><code>   PolylineOptions options = new PolylineOptions();
  
     options.add(lastLoc, curLoc);
  
     mMap.addPolyline(options.color(Color.RED).width(3));
  </code></pre>