title: change drawable shape parameter programmatically
body: <p>i a m looking to make a ring loading effect and to do that i have to change the dashWidth value.</p>
  
  <p>I want to do that programmatically.</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;stroke
      android:width="3dp"
      android:color="#8FFFFFFF" 
      android:dashWidth="304dp"
      android:dashGap="500dp"/&gt;
  
    &lt;size 
      android:width="100dp"
      android:height="100dp"/&gt;
  &lt;/shape&gt;
  </code></pre>