title: React - native StackNavigator refresh previous component after hitting back button
body: <p>I'm stuck for weeks on this problem that I can't solve. I have been through a lot of different solution and none of them is working..</p>
  
  <p>Let-s say I have  component A and component B </p>
  
  <p>Component A : contains a flatlist, when click on one item leads me to component B.</p>
  
  <p>Component B: contains details of component A items, when clicking on a button update data, data that component A is using in state current, which make the clicked items turn to orange. I would like when hitting back button to update those data in component A and actually have the clicked items in orange, right now nothing is happening..</p>
  
  <p>Component A :</p>
  
  <pre><code>async interventionList(){
      const planningList = await getInterventionList(this.state.userToken, '2019-02-27', '2019-02-27'); 
      this.setState({list: planningList});
   }
  
  renderItem = ({ item }) =&gt; (
      &lt;View&gt;
        &lt;TouchableHighlight onPress={
          () =&gt;  this.props.navigation.navigate('InterventionStart', { getIntervention: () =&gt; this.interventionsList() })}&gt;
          &lt;View style={[styles.block, this.state.current !== null &amp;&amp; this.state.current.remoteInterventionId === item.num ? styles.began : styles.notbegan]}&gt;
            &lt;Text&gt; {SomeData} &lt;Text&gt;
            &lt;/View&gt;
          &lt;/View&gt;
        &lt;/TouchableHighlight&gt;
      &lt;/View&gt;
    )
  </code></pre>
  
  <p>Component B : </p>
  
  <pre><code>componentWillUnmount() {
      this.props.navigation.state.params.getIntervention();
    }
  </code></pre>
  
  <p>But nothing happens. I tried to console log, to see if those functions where called after clickin on back button and they are... So I don't understand what I am doing wrong or is it not the way to do this at all ? </p>