title: react-native - Picker - undefined is not an object (evaluating 'this.props.children[position].props)
body: <p>I am encountering a weird behaviour when using Picker.</p>
  
  <p>I use a Picker as follows :</p>
  
  <pre><code>&lt;Picker
    mode="dropdown"
    style={styles.pickerField}
    selectedValue={this.state.dayAndTime}
    onValueChange={(text) =&gt; this.setState({ dayAndTime: text })}
  &gt;
    &lt;Picker.Item label="Le 5/07 à 15H" value="0" key="0" /&gt;
  &lt;/Picker&gt;
  </code></pre>
  
  <p>When the screen displaying this picker is loaded, I got an error screen saying (cf. screenshot below) : undefined is not an object (evaluating 'this.props.children[position].props)</p>
  
  <p>From what I gathered, my problem come from line 106 of Libraries/Components/Picker/PickerAndroid.android.js, it seems that having a property "onValueChange" triggers it. I removed it, and error didn't happen.</p>
  
  <p>I use react-native 0.31.0, I use an android api 23 virtual device with genymotion.</p>
  
  <p>Is there something something I am doing wrong ?</p>
  
  <p><a href="https://i.stack.imgur.com/Ub2ie.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Ub2ie.png" alt="enter image description here"></a></p>