title: Using react natives picker
body: <p>I am trying out picker in my react native project and this example i took directly from the react native docs</p>
  
  <pre><code>&lt;CardItem&gt;
  &lt;Item  floatingLabel&gt;
  &lt;Label&gt;Airtime Amount&lt;/Label&gt;
  &lt;Picker selectedValue={this.state.language} onValueChange={(lang) =&gt; this.setState({language: lang})}&gt; &lt;Picker.Item label="Java" value="java" /&gt; &lt;Picker.Item label="JavaScript" value="js" /&gt;&lt;/Picker&gt;
  &lt;/Item&gt;
  &lt;/CardItem&gt;
  </code></pre>
  
  <p>This is the source <a href="http://facebook.github.io/react-native/docs/picker.html" rel="nofollow noreferrer">http://facebook.github.io/react-native/docs/picker.html</a></p>
  
  <p>I get the error</p>
  
  <pre><code>null is not an object (evaluating 'this.state.language')
  </code></pre>
  
  <p>How can i correct this.
      render</p>
  
  <p>My class starts like this</p>
  
  <pre><code>class Form extends Component {
  
    static propTypes = {
      openDrawer: React.PropTypes.func,
    }
  ....
  </code></pre>