title: Set height of picker with react-native
body: <p>I have a picker in my react-native ios app and want to set the height but the example won't honor flex, a style height or a height attribute.</p>
  
  <pre><code>&lt;Picker
      style={[styles.testbox, {borderColor: '#00F', flex:1, height: 100}]}
      selectedValue={this.state.language}
      height={100}
      onValueChange={(itemValue, itemIndex) =&gt; this.setState({language: itemValue})}&gt;
      &lt;Picker.Item label="Java" value="java" /&gt;
      &lt;Picker.Item label="JavaScript" value="js" /&gt;
  &lt;/Picker&gt;
  </code></pre>