title: How to use React Native Animate to change view flex from 0 to 1
body: <p>I have two views inside another view which has default flexDirection style so it is columnar. When the user clicks on an item in the bottom view (marked options below), I want the top view to animate to to be equal sizes with the bottom view and display the details of the selected option. </p>
  
  <pre><code>state = {
      animation: new Animated.Value(0)
  }
  
  ...
  
  &lt;View style={{flex: 1}}&gt;
    &lt;Animated.View style={{ flex: this.state.animation}}&gt;
        {...details}
    &lt;/Animated.View&gt;
    &lt;View style={{flex:1}}&gt;
        {...options}
    &lt;/View&gt;
  &lt;/View&gt;
  </code></pre>
  
  <p>I am using the below method to change the value to grow the flex to 1.</p>
  
  <pre><code>onPress = () =&gt; {
      Animated.timing(this.state.animation, {
          toValue: 1,
          duration: 1000
      }).start()
  }
  </code></pre>
  
  <p>The issue I am running into is there is no animation, it just instantly appears no matter the duration I set. </p>