title: Android Google Map : how can I draw a line on Google Map with using the x and y of phone's screen?
body: <p>I have a Google Map in my android project. I's set it in specific center and zoom. I disable scroll and zoom. I want to add a line on the specific location of the phone. for example I want to add a line from p1(100,200) to p2(300,400). </p>
  
  <p>problem is that : android use x and y of map (I think, I'm not sure), but I want to use the x and y of my phone screen. How can I fix that?</p>
  
  <pre><code>Point p1,p2;
  LatLng l1,l2;           
  googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(origin,21));
  proj = googleMap.getProjection();
  
  p1=new Point(100,200);
  l1=proj.fromScreenLocation(p1);
  p2=new Point(300,400);
  l2=proj.fromScreenLocation(p2);
  googleMap.addPolyline(new PolylineOptions().add(l1).add(l2).width(10).color(Color.GREEN));
  </code></pre>