title: Layout a button from superview's bottom in react-native
body: <p>I wanna render a button in react native like this:</p>
  
  <p><a href="https://i.stack.imgur.com/Gn7q4.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Gn7q4.png" alt="enter image description here"></a></p>
  
  <p>Hear is my code :</p>
  
  <pre><code>    class Test extends Component {
        render() {
          return (
            &lt;View&gt;
              &lt;TouchableHighlight style={{marginBottom:20,height:40,backgroundColor:'blue',justifyContent:'center'}}&gt;
              &lt;Text style={{alignSelf:'center',color:'white'}}&gt;Login&lt;/Text&gt;
              &lt;/TouchableHighlight&gt;          
            &lt;/View&gt;
          );
        }
     }
  </code></pre>
  
  <p>But the render result for mentioned above is :</p>
  
  <p><a href="https://i.stack.imgur.com/N6lK7.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/N6lK7.png" alt="enter image description here"></a></p>
  
  <p>How to modify my code？</p>