title: Border opacity - React Native
body: <p>I applied a border to a 'View' and I want to know how can I change the opacity of the border.</p>
  
  <pre><code>&lt;View style={styles.mainContainer}&gt; &lt;/View&gt;
  
  mainContainer: {
   borderWidth: 2,
   borderColor: '#ddd',
   ....
   opacity: 2,
   ....
  }
  </code></pre>
  
  <p>It is not working when I applied the style as above.</p>