悬浮分组列表实现代码如下：

/**
 * Sample React Native App
 * https://github.com/facebook/react-native
 * @flow
 */

import React, { Component } from 'react';
import {
  AppRegistry,
  StyleSheet,
  Text,
  View,
  SectionList,
  TouchableOpacity,
} from 'react-native';
// 初始化总数据
var AllArr=[
           {name:'河北省',citys:[{name:'石家庄'},{name:'沧州'},{name:'邢台'},{name:'邯郸'},{name:'衡水'}]},
           {name:'山西省',citys:[{name:'太原'},{name:'大同'},{name:'阳泉'},{name:'临汾'},{name:'晋城'}]},
           {name:'辽宁省',citys:[{name:'沈阳市'},{name:'大连市'},{name:'鞍山市'},{name:'抚顺市'},{name:'本溪市'}]},
           {name:'吉林省',citys:[{name:'长春市'},{name:'吉林市'},{name:'四平市'},{name:'辽源市'},{name:'通化市'}]},
           {name:'黑龙江省',citys:[{name:'哈尔滨'},{name:'齐齐哈尔'},{name:'双鸭山'}]},
           {name:'江苏省',citys:[{name:'南京'},{name:'苏州'},{name:'无锡'},{name:'常州'}]},
           {name:'浙江省',citys:[{name:'杭州市'},{name:'宁波'},{name:'温州'},{name:'嘉兴'},{name:'湖州'}]},
           ];
export default class MySectionList extends Component {
    constructor(props) {
      super(props);
    
      this.state = {
      //改变数据的数组
        Arr:[
           {name:'河北省',citys:[{name:'石家庄'},{name:'沧州'},{name:'邢台'},{name:'邯郸'},{name:'衡水'}]},
           {name:'山西省',citys:[{name:'太原'},{name:'大同'},{name:'阳泉'},{name:'临汾'},{name:'晋城'}]},
           {name:'辽宁省',citys:[{name:'沈阳市'},{name:'大连市'},{name:'鞍山市'},{name:'抚顺市'},{name:'本溪市'}]},
           {name:'吉林省',citys:[{name:'长春市'},{name:'吉林市'},{name:'四平市'},{name:'辽源市'},{name:'通化市'}]},
           {name:'黑龙江省',citys:[{name:'哈尔滨'},{name:'齐齐哈尔'},{name:'双鸭山'}]},
           {name:'江苏省',citys:[{name:'南京'},{name:'苏州'},{name:'无锡'},{name:'常州'}]},
           {name:'浙江省',citys:[{name:'杭州市'},{name:'宁波'},{name:'温州'},{name:'嘉兴'},{name:'湖州'}]},
           ]
      };
    //for循环添加字段删除字段添加标示和key
    for (var i = 0; i < this.state.Arr.length; i++) {
       this.state.Arr[i]['data'] = [];
       this.state.Arr[i]['key'] = i;
       this.state.Arr[i]['isShow'] = 'off';
       delete this.state.Arr[i]['citys'];

    }
    }
  //分组创建的cell
  Cell(data){
    return(
      <View style={{height:40,backgroundColor:'green',justifyContent: 'center',}}>
          <View style={{height:39,backgroundColor:'yellow',justifyContent: 'center',}}>
          <Text>{data.item.name}</Text>
          </View>
      </View>
    );
  }
  // 展开改变数据源，增加数据，合上删除数组里的数据，根据isShow状态判断
  show(data){
       if (data.isShow==='off') {
         this.state.Arr[data.key]['data'] = AllArr[data.key].citys;
         this.state.Arr[data.key]['isShow'] = 'on';
         this.setState({
            Arr:this.state.Arr,
         }); 
     }else{
        this.state.Arr[data.key]['data'] = [];
        this.state.Arr[data.key]['isShow'] = 'off';
        this.setState({
          Arr:this.state.Arr,
        });  
     }
       
  }
  //列表分组的header
  Header({section}){
    return(
      <TouchableOpacity style={{height:50,
                                backgroundColor:'orange',
                                justifyContent: 'center',}}
                        onPress={()=>{this.show(section)}}>
        <View>
         <Text style={{fontSize:20}}>{section.name}</Text>
        </View>
      </TouchableOpacity>
    );
  }
  //去除警告
  extraUniqueKey(item,index){
    return index+item;
  }
  render() {
    console.log('========'+JSON.stringify(this.state.Arr));
    return (
      <View style={styles.container}>
       <SectionList 
                    sections={this.state.Arr}//数据源
                    renderItem={this.Cell.bind(this)}//cell绑定时间创建cell
                    keyExtractor = {this.extraUniqueKey}//去除警告 
                    renderSectionHeader={this.Header.bind(this)}//Header绑定时间创建表头
                    scrollEnabled={true}//默认是true，false禁止滚动

                    >
       </SectionList>
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#F5FCFF',
  },
  welcome: {
    fontSize: 20,
    textAlign: 'center',
    margin: 10,
  },
  instructions: {
    textAlign: 'center',
    color: '#333333',
    marginBottom: 5,
  },
});

AppRegistry.registerComponent('MySectionList', () => MySectionList);

实现效果如下：

QQ20170816-115757-HD.gif