title: FlatList use numColumns shows Elements type is invalid
body: <p>I use FlatList to show image like this:
  <a href="https://i.stack.imgur.com/MVLz3.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/MVLz3.jpg" alt="enter image description here"></a></p>
  
  <p>But when i add <code>numColumns={2}</code> in <code>FlatList</code> it will show the error:</p>
  
  <pre><code>Element type is invalid
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/7Ir5f.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/7Ir5f.png" alt="enter image description here"></a></p>
  
  <p>The strange thing is there is no error if i use <code>numColumns={1}</code></p>
  
  <p>I can't figure it out. Any one can give me some suggestion ? Thanks in advance.</p>
  
  <p>Here is i use my FlatList code</p>
  
  <pre><code>import {
    View,
    Text,
    StatusBar,
    FlatList,
    Image,
    Dimensions
  } from "react-native";
  
  const { width, height } = Dimensions.get("window");
  const equalWidth = width / 2;
  
  class MainActivity extends Component {
    renderItem = ({ item }) =&gt; {
      return item.map(value =&gt; {
        return (
          &lt;View&gt;
            &lt;Image
              style={{ height: 150, width: equalWidth }}
              source={{ uri: value.photoHref }}
              resizeMode="cover"
            /&gt;
          &lt;/View&gt;
        );
      });
    };
  
    render() {
      return (
        &lt;FlatList
          data={movieData}
          renderItem={this.renderItem}
          horizontal={false}
          keyExtractor={(item, index) =&gt; index}
          numColumns={2}
        /&gt;
      );
    }
  }
  </code></pre>