title: React native setState() not re-render as expected
body: <p>I made a carousel with react-native-snap-carousel and below are the code for carousel. In carousel there're picker and textInput and etc.
  For render function:</p>
  
  <pre><code>&lt;Carousel
              ref={(c) =&gt; { this._carousel = c; }}
              data={this.state.question}
              renderItem={this._renderItem}
              sliderWidth={standard * 1.1}
              itemWidth={standard * 0.9}
  
              inactiveSlideScale={0.9}
              inactiveSlideOpacity={0.7}
  
              firstItem={0}
  
              activeSlideAlignment={'center'}
              containerCustomStyle={styles.slider}
              contentContainerCustomStyle={styles.sliderContentContainer}
                /&gt;
  </code></pre>
  
  <p>For detail rendering:</p>
  
  <pre><code>_renderItem ({item, index}) {
    var content;
    switch (item.id) {
        case 1:
            content = &lt;View style={styles.carousel_cell}&gt;
                          &lt;Text style={styles.carouselItemTitle}&gt;{item.displayLabel}&lt;/Text&gt;
                          &lt;TextInput style={styles.editor} onChangeText={(text) =&gt; this.setState({comment: text})} value={this.state.comment} /&gt;
                      &lt;/View&gt;;
            break;
        case 2:
            content = &lt;View style={styles.carousel_cell}&gt;
                          &lt;Text style={styles.carouselItemTitle}&gt;{item.displayLabel}&lt;/Text&gt;
                          &lt;Picker mode="dropdown"
                          style={styles.picker}
                          selectedValue={this.state.priority}
                          onValueChange={(itemValue) =&gt; this.onPriorityChange(itemValue)}&gt;
  
                            {this.state.list}
                          &lt;/Picker&gt;
  
                      &lt;/View&gt;;
            break;
        default:
            content = &lt;View style={styles.carousel_cell}&gt;
                          &lt;Text style={styles.carouselItemTitle}&gt;{item.displayLabel}&lt;/Text&gt;
                          &lt;Text&gt;Unknown&lt;/Text&gt;
                      &lt;/View&gt;;
            break;
  
    }
  
    return content;
  </code></pre>
  
  <p>}</p>
  
  <p>For event triggering:</p>
  
  <pre><code>onPriorityChange(value) {
      this.setState({priority: value});
  }
  </code></pre>
  
  <p>The problem here is that after I select any item in Picker the state did get updated but on the interface it's not. The render function of Picker will be invoked once I trigger the onChangeText event. At that time the display in Picker will be update as well.
  However, according to the life cycle, shouldn't the carousel(including its cells) be updated/re-rendered when I setState?</p>
  
  <p>The Stopwatch(from react-native-stopwatch-timer) in carousel will have the same problem.</p>