title: Call function of header component in react native navigation
body: <p>I have the code:</p>
  
  <pre><code>class Parent extends React.Component {
     static navigationOptions = {
        title: 'Parent',
        headerRight: &lt;HeaderComponent /&gt;
     }
  
     render() { return (&lt;Button onPress={...} /&gt;); }
  }
  </code></pre>
  
  <p>Along with:</p>
  
  <pre><code>class HeaderComponent extends React.Component {
     ...
  
     playAnimationOnce = () =&gt; { ... }
  }
  </code></pre>
  
  <p>Now what I want to do, is I want to be able to call the <code>playAnimation</code> function of the <code>HeaderComponent</code> class when I press the <code>Button</code> in the <code>Parent</code> class (so basically where the <code>...</code> is located). How would I go on doing this?</p>