title: Google Maps API v2 Android add shape drawable as marker
body: <p>I've been trying to add a shape drawable as the marker icon for a marker I want to add on the map.</p>
  
  <p>shape looks like this (res/drawable/blue_circle.xml):</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;shape xmlns:android="http://schemas.android.com/apk/res/android"
      android:shape="oval" &gt;
      &lt;size
          android:width="15dp"
          android:height="15dp" /&gt;
      &lt;solid
          android:color="@color/Blue" /&gt;
  &lt;/shape&gt;
  </code></pre>
  
  <p>and I try to add the marker like this:</p>
  
  <pre><code>markerOptions.icon(BitmapDescriptorFactory.fromResource(R.drawable.blue_circle));
  </code></pre>
  
  <p>Apparently I get a NullPointer exception.</p>
  
  <p>Must the marker icon be a bitmap?
  Am I allowed to add shapes drawables as marker icons?
  And if yes what am I doing wrong?</p>