问当我相应地在react native中滚动时，需要突出显示菜单

EN

class List extends Component {
    constructor(props) {
      super(props);
      this.arr = [];
    }
    onPressFilter(val) {
        this.setState({ selectedTab: val });
        let dynamicIndex = categoryArr.indexOf(val);
        this.refs._scrollView.scrollTo({
            x: 0,
            y: this.arr[dynamicIndex] - 55,
            animated: true,
        });
    }
    render(){
        return (
            <ScrollView>
                <ScrollView ref='_scrollView'>
                    {{this.props.data.map((val, index) =>
                      <TouchableOpacity 
                        style={[styles.filterItem, (selectedTab === val) && {backgroundColor: themeColor}]}
                        onPress={this.onPressFilter.bind(this, val)} key={index}>
                          <Text style={[styles.filterText, (selectedTab === val) && {color: '#fff'}]}>{val.toUpperCase()}</Text>
                      </TouchableOpacity>)}}
                </ScrollView>
                {CategoryList.map((el, key) => (<View key={key}
                  onLayout={event => {
                    const layout = event.nativeEvent.layout;
                    this.arr[key] = layout.y;
                  }}>
                  <View style={{paddingHorizontal: 20, paddingVertical: 10}}>
                    <H2>{el.toUpperCase()}</H2>
                  </View>
                  <FlatList
                    data={DATA.filter((a, i) => a.category.name === el)}
                    renderItem={({ item }) => <Item item={item} data={DATA} />}
                    keyExtractor={item => item.id}
                  />
                </View>))}
            </ScrollView>
        )
    }
}