title: React Native - Using "flex" inside a FlatList
body: <p>I'm starting to learn React Native, and I'm trying to create grid of 3 columns with images. I've been using the <code>numColumns</code> prop of the FlatList to specify 3 columns, and then setting <code>flex:1</code> for my images so they should fill the space of the column. However <code>flex:1</code> makes none of my images appear, while trying <code>height:100,aspectRatio:1</code> shows all of my images in columns. Any idea why this is? My code is down below:</p>
  
  <pre><code>export default class ArtScrollView extends React.Component {
      _renderItem = (item) =&gt;
          (
              &lt;Image style={styles.art} source={{uri:item.item.imgFilePath}}/&gt;
          )
      render() {
          return(
              &lt;FlatList numColumns={3}
              data={Object.values(this.props.pods)}
              renderItem={this._renderItem}/&gt;
          );
      }
  }
  
  const styles = StyleSheet.create({
      art:{
          height:100,
          aspectRatio:1,
          //flex:1, &lt;- Having this instead of specifying the height doesn't work
          marginRight:10,
      }
    });
  </code></pre>