title: Creating an indoor map using GridLayout
body: <p>I am looking to implement an indoor mapping application similar to Google Indoors but for a private building with a floor plan. So far I have managed to implement a location tracking for the user and compass to point in the direction the user is facing. The main segment which I wish to now include is to create a polyline from the user's start location (main entrance of the building) to their desired location (for example a particular room). </p>
  
  <p>I have currently thought about how to create this and had decided to build a custom floor plan using XML. The rooms will be populated within a GridLayout. I wanted to use the GridLayout so that when the user selects the desired room they want to navigate to, a polyline will be draw automatically from their current location - this will be along the grid so that the polyline doesn't pass through walls and avoids obstacles. </p>
  
  <p>The main issue I am currently facing is that I am not sure how to enable the visibility of the gridlines in GridLayout and how to ensure that only certain lines are shown to represent the polyline from the user's location to the room. I researched and tried to implement to see how to make the gridlines visible but it doesn't show a grid the way I want it to. </p>
  
  <p>My research: <a href="https://android--code.blogspot.co.uk/2015/08/android-gridview-border-between-items.html" rel="nofollow noreferrer">https://android--code.blogspot.co.uk/2015/08/android-gridview-border-between-items.html</a></p>
  
  <p>This is the grid which I want to build but only certain lines should be visible to form a trail for the user to follow: <a href="https://www.google.co.uk/search?q=grid&amp;source=lnms&amp;tbm=isch&amp;sa=X&amp;ved=0ahUKEwjv3r7virDXAhWCchoKHYE5DZ0Q_AUICigB&amp;biw=1440&amp;bih=723#imgrc=JjtkEUfXr72rQM" rel="nofollow noreferrer">https://www.google.co.uk/search?q=grid&amp;source=lnms&amp;tbm=isch&amp;sa=X&amp;ved=0ahUKEwjv3r7virDXAhWCchoKHYE5DZ0Q_AUICigB&amp;biw=1440&amp;bih=723#imgrc=JjtkEUfXr72rQM</a></p>
  
  <p>A polyline created like this for example but not passing through walls: <a href="https://www.google.co.uk/search?biw=1440&amp;bih=723&amp;tbm=isch&amp;sa=1&amp;ei=mI4DWs-wEsW8aYKCiLgK&amp;q=indoor+maps+polyline&amp;oq=indoor+maps+polyline&amp;gs_l=psy-ab.3...4135.6341.0.6690.13.10.3.0.0.0.136.912.8j2.10.0....0...1.1.64.psy-ab..2.0.0....0.qyp2uWQ80Uc#imgrc=CyhdXvDeTS7qhM" rel="nofollow noreferrer">https://www.google.co.uk/search?biw=1440&amp;bih=723&amp;tbm=isch&amp;sa=1&amp;ei=mI4DWs-wEsW8aYKCiLgK&amp;q=indoor+maps+polyline&amp;oq=indoor+maps+polyline&amp;gs_l=psy-ab.3...4135.6341.0.6690.13.10.3.0.0.0.136.912.8j2.10.0....0...1.1.64.psy-ab..2.0.0....0.qyp2uWQ80Uc#imgrc=CyhdXvDeTS7qhM</a>:</p>
  
  <p>Can you please let me know if this is a good approach and how I can go about implementing this or whether there is a better approach for this?</p>
  
  <p>Any help is appreciated. Many thanks!</p>