title: change corner radius of drawable programmatically
body: <p>I have this shape defined in an 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="rectangle"&gt;
      &lt;gradient
          android:startColor="#FFFF0000"
          android:endColor="#80FF00FF"
          android:angle="45"/&gt;
      &lt;padding android:left="7dp" 
          android:top="7dp"
          android:right="7dp"
          android:bottom="7dp" /&gt;
      &lt;corners
          android:bottomLeftRadius="5dp"    ##this need change
          android:bottomRightRadius="5dp"   ##this need change
          android:topLeftRadius="5dp"       ##this need change
          android:topRightRadius="5dp" /&gt;   ##this need change
  &lt;/shape&gt;
  </code></pre>
  
  <p>I am creating  the following object:</p>
  
  <p><code>Drawable shape = getResource().getDrawable(R.drawable.myshape);</code></p>
  
  <p>and I need to modify its radius (or create one with another corner radius).</p>
  
  <p>How can I change the radius? How can I create the shape programmatically?</p>