app/lib/paegs/home_page/home_page.dart

import 'dart:async';
import 'dart:convert';
import 'dart:math';

import 'package:address_picker/address_picker.dart';
import 'package:bbyyy/beans/ad_bean_entity.dart';
import 'package:bbyyy/beans/commodity_category_bean_entity.dart';
import 'package:bbyyy/beans/goods_bean_entity.dart';
import 'package:bbyyy/beans/home_carousel_bean_entity.dart';
import 'package:bbyyy/beans/my_shop_bean_entity.dart';
import 'package:bbyyy/beans/store_bean_entity.dart';
import 'package:bbyyy/https/MyDio.dart';
import 'package:bbyyy/https/my_request.dart';
import 'package:bbyyy/https/url.dart';
import 'package:bbyyy/my_tools/const.dart';
import 'package:bbyyy/my_tools/dims.dart';
import 'package:bbyyy/my_tools/event_bus.dart';
import 'package:bbyyy/my_tools/my_colors.dart';
import 'package:bbyyy/my_tools/my_cookie.dart';
import 'package:bbyyy/my_tools/my_tools.dart';
import 'package:bbyyy/my_tools/my_views.dart';
import 'package:bbyyy/paegs/home_page/recommended_today_page.dart';
import 'package:bbyyy/paegs/root_page/root_page_view.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter_svg/flutter_svg.dart';
import 'package:flutter_swiper/flutter_swiper.dart';
import 'package:pull_to_refresh/pull_to_refresh.dart';

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage>
    with AutomaticKeepAliveClientMixin {
  var data = [];
  var container = [];
  var puShop = [];
  var imgs = ['images/banner1.png', 'images/banner2.png', 'images/banner3.png'];
  var netImgs = [];
  int selectedIndex = 0;
  var tabs = ['全部'];
  var types = ['货帮', '货品'];
  List<DropdownMenuItem<String>> sortItems = [];
  int typeIndex = 1;
  List<MyShopBeanDataData> shops = [];
  ScrollController _controller = ScrollController();
  double maxH;
  double minH = 164;
  double H = 0;
  bool showInput = false;
  TextEditingController _description = TextEditingController();
  FocusNode _descriptionFocus = FocusNode();

  RefreshController _reController = RefreshController(initialRefresh: true);
  int page = 1;
  int pageIndex = 0;
  bool showS = false;
  String province;
  String city;
  Address _address;

  @override
  void initState() {
    super.initState();
    EventBus().on('commodity_category', (arg) {
      setState(() {});
    });
    EventBus().on('uploadGoods', (arg) {
      _reController.requestRefresh();
    });
    EventBus().on('toTop', (arg) {
      _controller.animateTo(0.0,
          duration: Duration(milliseconds: 200), curve: Curves.easeIn);
    });
    EventBus().on('homeCarousel', (arg) {
      if (arg is HomeCarouselBeanEntity) {
        arg.data.forEach((element) {
          netImgs.add(element.path);
        });
        setState(() {});
      }
    });
    EventBus().on('商品变动', (arg) {
      _reController.requestRefresh();
    });
    EventBus().on('getLocation', (arg) {
      _reController.requestRefresh();
      setState(() {});
    });
    _controller.addListener(() {
      setState(() {
        if (_controller.offset == 0) {
          RootPageView().toTop = false;
          EventBus().emit('ChangePage');
        } else {
          RootPageView().toTop = true;
          EventBus().emit('ChangePage');
        }
        H = maxH - _controller.offset;
        if (H < minH) {
          H = minH;
        } else if (H > maxH) {
          H = maxH;
        }
      });
    });
    types.forEach((element) {
      sortItems.add(DropdownMenuItem(
        child: Text(
          element,
          style: TextStyle(color: MyColors.c666666, fontSize: 14),
        ),
        value: element,
      ));
    });
    _descriptionFocus.addListener(() {
      if (_descriptionFocus.hasFocus) {
      } else {
        if (_description.text.isEmpty) {
          showInput = false;
        }
      }
    });
    homeCarousel();
  }

  @override
  void dispose() {
    // TODO: implement dispose
    super.dispose();
    EventBus().off('commodity_category');
    EventBus().off('uploadGoods');
    EventBus().off('toTop');
    EventBus().off('homeCarousel');
    EventBus().off('商品变动');
    EventBus().off('getLocation');
  }

  @override
  Widget build(BuildContext context) {
    maxH = MediaQuery.of(context).size.width * (520 / 750);
    minH = MediaQuery.of(context).padding.top + 64;
    if (H == 0) {
      H = maxH;
    }
    return GestureDetector(
      onTap: () {
        MyTools().hideKeyboard(context);
      },
      behavior: HitTestBehavior.translucent,
      child: Scaffold(
        resizeToAvoidBottomInset: false,
        body: SmartRefresher(
          controller: _reController,
          onRefresh: onRefresh,
          onLoading: onLoading,
          enablePullDown: true,
          enablePullUp: true,
          child: CustomScrollView(
            slivers: [
              carouselAndSearch(context),
              // recommendedToday(),
              storeCategory(),
              shopList()
            ],
          ),
        ),
      ),
    );
  }

  Widget shopList() {
    return SliverList(
        delegate: SliverChildBuilderDelegate(
      (c, index) {
        return MyViews().pubShopItem(puShop[index], context);
      },
      childCount: puShop.length,
    ));
  }

  Widget storeCategory() {
    return SliverPersistentHeader(
        pinned: true, //是否固定在顶部
        floating: false,
        delegate: _SliverAppBarDelegate(
            minHeight: 54,
            maxHeight: 54,
            child: Column(
              children: [
                Container(
                  color: Colors.white,
                  height: 53,
                  child: ListView.builder(
                    padding: EdgeInsets.only(left: 12, right: 12),
                    itemBuilder: (c, index) {
                      return GestureDetector(
                        onTap: () {
                          setState(() {
                            selectedIndex = index;
                            _reController.requestRefresh();
                          });
                        },
                        behavior: HitTestBehavior.translucent,
                        child: Container(
                          padding:
                              EdgeInsets.only(right: 15, left: 15, bottom: 9),
                          child: Column(
                            children: [
                              Text(
                                tabs[index],
                                style: TextStyle(
                                    color: index == selectedIndex
                                        ? MyColors.cFF4233
                                        : MyColors.c666666,
                                    fontSize: 14),
                              ),
                              Container(
                                height: 10,
                                child: Visibility(
                                  child: SvgPicture.asset('images/svg/tab.svg'),
                                  visible: index == selectedIndex,
                                ),
                              )
                            ],
                            mainAxisAlignment: MainAxisAlignment.end,
                          ),
                          height: 53,
                        ),
                      );
                    },
                    itemCount: tabs.length,
                    scrollDirection: Axis.horizontal,
                  ),
                ),
                Container(
                  height: 1,
                  color: MyColors.cf2f2f2,
                ),
              ],
            )));
  }

  Widget recommendedToday() {
    return SliverToBoxAdapter(
      child: Column(
        children: [
          Container(
            padding: EdgeInsets.only(left: 16, right: 10),
            height: 54,
            child: Row(
              children: [
                Text(
                  '梆梆今日折扣',
                  style: TextStyle(color: MyColors.c333333, fontSize: 14),
                ),
                GestureDetector(
                  onTap: (){
                    MyTools().toPage(context, RecommendedTodayPage(), (then){});
                  },
                  behavior:HitTestBehavior.translucent,
                  child: Row(
                    children: [
                      Text(
                        '查看更多',
                        style: TextStyle(color: MyColors.c666666, fontSize: 12),
                      ),
                      Icon(
                        Icons.chevron_right,
                        color: MyColors.c666666,
                      )
                    ],
                  ),
                )
              ],
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
            ),
          ),
          Container(
            height: 1,
            color: MyColors.cf2f2f2,
          ),
          Container(
            height: 168,
            child: ListView.builder(
              padding: EdgeInsets.symmetric(horizontal: 16, vertical: 15),
              itemBuilder: (c, index) {
                return Container(
                  margin: EdgeInsets.only(right: 10),
                  height: 138,
                  width: 100,
                  padding: EdgeInsets.all(5),
                  decoration: BoxDecoration(
                    boxShadow: [
                      BoxShadow(
                        color: MyColors.c7FE1E1E1,
                        blurRadius: 5.0,
                      ),
                    ],
                    color: Colors.white,
                    borderRadius: BorderRadius.circular(4),
                  ),
                  child: Column(
                    children: [
                      MyViews().netImg('', 90, 90,
                          placeholder: 'images/svg/goodsDefImg.svg'),
                      Text(
                        '8.9元充10元话费',
                        style: TextStyle(color: MyColors.c333333, fontSize: 11),
                        maxLines: 1,
                        overflow: TextOverflow.ellipsis,
                        softWrap: true,
                      ),
                      Row(
                        children: [
                          Text(
                            '¥8.90',
                            style: TextStyle(
                                color: MyColors.cFF4233,
                                fontSize: 13,
                                fontWeight: FontWeight.bold),
                            maxLines: 1,
                            overflow: TextOverflow.ellipsis,
                            softWrap: true,
                          ),
                          Container(
                            decoration: BoxDecoration(
                              border:
                                  Border.all(color: MyColors.cFF4233, width: 1),
                              borderRadius: BorderRadius.circular(7),
                            ),
                            height: 14,
                            width: 30,
                            child: Text('详情',style: TextStyle(color: MyColors.cFF4233,fontSize: 9),),
                            alignment: Alignment.center,
                          )
                        ],mainAxisAlignment: MainAxisAlignment.spaceBetween,
                      )
                    ],mainAxisAlignment: MainAxisAlignment.spaceBetween,
                    crossAxisAlignment: CrossAxisAlignment.start,
                  ),
                );
              },
              itemCount: 10,
              scrollDirection: Axis.horizontal,
            ),
          ),
        ],
      ),
    );
  }

  Widget carouselAndSearch(BuildContext context) {
    return SliverPersistentHeader(
      pinned: true,
      floating: false,
      delegate: _SliverAppBarDelegate(
          minHeight: minH,
          maxHeight: maxH,
          child: Stack(
            children: [
              Swiper(
                itemBuilder: (BuildContext context, int index) {
                  return netImgs.length == 0
                      ? Image.asset(
                          "${imgs[index]}",
                          fit: BoxFit.cover,
                        )
                      : MyViews().netImg(
                          imgURL(netImgs[index]), H, double.infinity,
                          placeholder: 'images/svg/goodsDefImg.svg');
                },
                itemCount: netImgs.length == 0 ? imgs.length : netImgs.length,
                viewportFraction: 1,
                scale: 1,
                autoplay: true,
              ),
              SafeArea(
                bottom: false,
                child: Stack(
                  children: [
                    Positioned(
                      left: 0,
                      child: Container(
                        padding: EdgeInsets.only(left: 10, right: 10, top: 12),
                        child: GestureDetector(
                          onTap: () {
                            addressSelection();
                          },
                          behavior: HitTestBehavior.translucent,
                          child: Container(
                            padding: EdgeInsets.only(left: 11, right: 14),
                            decoration: BoxDecoration(
                                boxShadow: [
                                  BoxShadow(
                                    color: MyColors.c7FE1E1E1,
                                    blurRadius: 5.0,
                                  ),
                                ],
                                color: Colors.white,
                                borderRadius: BorderRadius.circular(20)),
                            child: Row(
                              children: [
                                Icon(
                                  Icons.location_on_rounded,
                                  color: MyColors.c333333,
                                  size: 20,
                                ),
                                Text(
                                  province == null
                                      ? MyCookie().location != null
                                          ? MyCookie().location.city
                                          : '成都市'
                                      : city,
                                  style: TextStyle(
                                      color: MyColors.c333333,
                                      fontSize: 12,
                                      fontWeight: FontWeight.bold),
                                ),
                              ],
                            ),
                            height: 40,
                            alignment: Alignment.center,
                          ),
                        ),
                        alignment: Alignment.center,
                      ),
                    ),
                    Positioned(
                      top: 0,
                      right: 0,
                      child: Container(
                        padding: EdgeInsets.only(left: 10, right: 10, top: 12),
                        child: GestureDetector(
                          onTap: () {
                            showS = !showS;
                            if (!showS) {
                              _description.clear();
                            }
                            setState(() {});
                          },
                          behavior: HitTestBehavior.translucent,
                          child: AnimatedContainer(
                            height: 40,
                            width: !showS
                                ? 40
                                : MediaQuery.of(context).size.width - 20,
                            child: Row(
                              children: [
                                SvgPicture.asset(
                                  showS
                                      ? 'images/svg/箭头.svg'
                                      : 'images/svg/搜索.svg',
                                  height: 15,
                                  width: 15,
                                  color:
                                      showS ? MyColors.cFF4233 : Colors.white,
                                ),
                                Visibility(
                                  visible: showS,
                                  child: Expanded(
                                    child: TextField(
                                      controller: _description,
                                      cursorColor: MyColors.cFF4233,
                                      cursorWidth: 1.0,
                                      onTap: () {},
                                      decoration: InputDecoration(
                                        border: InputBorder.none,
                                        disabledBorder: InputBorder.none,
                                        enabledBorder: InputBorder.none,
                                        focusedBorder: InputBorder.none,
                                        isDense: true,
                                        hintText: '请输入...',
                                        hintStyle: TextStyle(
                                            color: MyColors.c999999,
                                            fontSize: 16),
                                        contentPadding:
                                            const EdgeInsets.fromLTRB(
                                                14, 4.5, 8, 4.5),
                                      ),
                                      maxLines: 1,
                                      style: TextStyle(
                                          color: MyColors.c333333,
                                          fontSize: 16,
                                          height: 1.3,
                                          letterSpacing: 0.2),
                                      keyboardType: TextInputType.text,
                                      onChanged: (t) {
                                        setState(() {});
                                      },
                                    ),
                                  ),
                                ),
                                Visibility(
                                  visible:
                                      showS && _description.text.isNotEmpty,
                                  child: GestureDetector(
                                    onTap: () {
                                      MyTools().hideKeyboard(context);
                                      _reController.requestRefresh();
                                    },
                                    behavior: HitTestBehavior.translucent,
                                    child: Container(
                                      child: MyViews()
                                          .myText('搜索', Colors.white, 13),
                                      decoration: BoxDecoration(
                                        color: MyColors.cFF4233,
                                        borderRadius: BorderRadius.circular(20),
                                      ),
                                      height: 40,
                                      width: 80,
                                      alignment: Alignment.center,
                                    ),
                                  ),
                                )
                              ],
                              mainAxisAlignment: MainAxisAlignment.center,
                            ),
                            alignment: !showS
                                ? Alignment.center
                                : Alignment.centerLeft,
                            padding: EdgeInsets.only(left: !showS ? 0 : 12),
                            decoration: BoxDecoration(
                                borderRadius:
                                    BorderRadius.all(Radius.circular(20)),
                                color: showS ? Colors.white : MyColors.cFF4233,
                                border: Border.all(
                                    width: 0.5,
                                    color: showS
                                        ? MyColors.cf2f2f2
                                        : MyColors.cFF4233)),
                            duration: Duration(milliseconds: 200),
                          ),
                        ),
                        alignment: Alignment.centerRight,
                      ),
                    ),
                  ],
                ),
              ),
            ],
          )),
    );
  }

  @override
  // TODO: implement wantKeepAlive
  bool get wantKeepAlive => true;

  void getGoods(List<dynamic> shopUID) {
    var qData;
    if (shopUID.length == 0) {
      var conditions = ["public == true", "on_sale == true"];
      if (selectedIndex != 0) {
        conditions.add("category == ${tabs[selectedIndex]}");
      }
      if (_description.text.isNotEmpty) {
        conditions.add('title LIKE ${_description.text.toString()}');
      }
      qData = {
        "key": "commodity",
        "filters": {"conditions": conditions},
        "dims": commodityDims,
        "order_by": ["id,desc", "no,desc"],
        "paging": [page, 20]
      };
    } else {
      var conditions = ["shop_uid in $shopUID", "on_sale == true"];
      var conditions2 = ["public == true", "on_sale == true"];
      if (selectedIndex != 0) {
        conditions.add("category == ${tabs[selectedIndex]}");
        conditions2.add("category == ${tabs[selectedIndex]}");
      }
      if (_description.text.isNotEmpty) {
        conditions.add('title LIKE ${_description.text.toString()}');
        conditions2.add('title LIKE ${_description.text.toString()}');
      }
      qData = {
        "key": "commodity",
        "filters": {
          "or": true,
          "conditions": conditions,
          "filters": [
            {"conditions": conditions2}
          ]
        },
        "order_by": ["id,desc", "no,desc"],
        "dims": commodityDims,
        "paging": [page, 20]
      };
    }

    MyDio().query(qData, (response, hasError) {
      if (!hasError) {
        GoodsBeanEntity entity =
            GoodsBeanEntity().fromJson(json.decode(response.data.toString()));
        container.clear();
        container.addAll(entity.data.data);
      }
      queryAd();
    }, (error) {
      queryAd();
    });
  }

  void onRefresh() {
    page = 1;
    if (pageIndex == 1) {
      initTabs();
      findAStore();
    } else {
      storeType();
      checkPublicStores();
    }
  }

  void onLoading() {
    page++;
    if (pageIndex == 1) {
      findAStore();
    } else {
      checkPublicStores();
    }
  }

  Future<void> initTabs() async {
    List<CommodityCategoryBeanData> commodityCategoryBeanData = [];
    MyDio().query({
      "key": "commodity_category",
      "filters": {},
      "dims": [
        "name",
      ]
    }, (response, hasError) {
      if (!hasError) {
        try {
          CommodityCategoryBeanEntity entity = CommodityCategoryBeanEntity()
              .fromJson(json.decode(response.data.toString()));
          commodityCategoryBeanData = entity.data;
          tabs.clear();
          tabs.add('全部');
          commodityCategoryBeanData.forEach((element) {
            tabs.insert(1, element.name);
          });
          if (selectedIndex > tabs.length - 1) {
            selectedIndex = 0;
          }
          setState(() {});
        } catch (e) {
          tabs.clear();
          tabs.add('全部');
          if (selectedIndex > tabs.length - 1) {
            selectedIndex = 0;
          }
        }
      } else {
        return commodityCategoryBeanData;
      }
    }, (error) {
      return commodityCategoryBeanData;
    });
  }

  findAStore() {
    MyDio().query({
      "key": "shop_user",
      "filters": {
        "or": true,
        "conditions": [
          "role!=$shopUserOwner",
          "user_uid==${MyCookie().getUID()}",
          "review_state==1"
        ],
        "filters": [
          {
            "conditions": [
              "role==$shopUserOwner",
              "user_uid==${MyCookie().getUID()}"
            ]
          }
        ]
      },
      "dims": shopUserDims,
      "paging": [1, 20000]
    }, (response, hasError) {
      if (!hasError) {
        MyShopBeanEntity entity =
            MyShopBeanEntity().fromJson(json.decode(response.data.toString()));
        shops = entity.data.data;
        var shopUID = [];
        shops.forEach((element) {
          shopUID.add(element.shopUid);
        });
        getGoods(shopUID);
      }
    }, (error) {});
  }

  queryAd() {
    int count = 5;
    MyDio().query({
      "key": "ad",
      "filters": {
        "conditions": ['on_show == true']
      },
      "dims": adDims,
      "order_by": ["id,desc", "no,desc"],
      "paging": [page, count]
    }, (response, hasError) {
      if (!hasError) {
        AdBeanEntity entity =
            AdBeanEntity().fromJson(json.decode(response.data.toString()));
        container.addAll(entity.data.data);
        container.shuffle();
      }
      if (page == 1) {
        data.clear();
        puShop.clear();
      }
      if (pageIndex == 1) {
        data.addAll(container);
      } else {
        puShop.addAll(container);
      }
      setState(() {});
      endRe(_reController);
    }, (error) {
      if (page == 1) {
        data.clear();
      }
      data.addAll(container);
      setState(() {});
      endRe(_reController);
    });
  }

  void checkPublicStores() {
    var conditions = ['private==false', 'state == $shopStateNormal'];
    if (selectedIndex != 0) {
      conditions.add("category == ${tabs[selectedIndex]}");
    }
    if (_description.text.isNotEmpty) {
      conditions.add('name LIKE ${_description.text.toString()}');
    }
    if (MyCookie().location == null && province == null) {
      conditions.add('province == 四川省');
      conditions.add('city == 成都市');
    } else {
      if (province != null) {
        conditions.add('province == $province');
        conditions.add('city == $city');
      } else if (MyCookie().location != null) {
        conditions.add('province == ${MyCookie().location.province}');
        conditions.add('city == ${MyCookie().location.city}');
      }
    }
    MyDio().query({
      "key": "shop",
      "filters": {"conditions": conditions},
      "dims": shopDims,
      "order_by": ["id,desc", "no,desc"],
      "paging": [page, 20]
    }, (response, hasError) {
      if (!hasError) {
        StoreBeanEntity entity =
            StoreBeanEntity().fromJson(json.decode(response.data.toString()));
        container.clear();
        container.addAll(entity.data.data);
      }
      queryAd();
    }, (error) {
      queryAd();
    });
  }

  void storeType() {
    List<CommodityCategoryBeanData> commodityCategoryBeanData = [];
    MyDio().query({
      "key": "shop_category",
      "filters": {},
      "dims": [
        "name",
      ]
    }, (response, hasError) {
      if (!hasError) {
        try {
          CommodityCategoryBeanEntity entity = CommodityCategoryBeanEntity()
              .fromJson(json.decode(response.data.toString()));
          commodityCategoryBeanData = entity.data;
          tabs.clear();
          tabs.add('全部');
          commodityCategoryBeanData.forEach((element) {
            tabs.insert(1, element.name);
          });
          setState(() {});
        } catch (e) {
          tabs.clear();
          tabs.add('全部');

          if (selectedIndex > tabs.length - 1) {
            selectedIndex = 0;
          }
          setState(() {});
        }
      }
    }, (error) {});
  }

  void addressSelection() {
    StateSetter ss;
    showModalBottomSheet(
      context: context,
      builder: (context) => BottomSheet(
        onClosing: () {},
        builder: (context) => Container(
          height: 350,
          child: Column(
            children: [
              StatefulBuilder(
                builder: (c, s) {
                  ss = s;
                  return Container(
                    height: 40,
                    color: Colors.white,
                    padding: EdgeInsets.symmetric(horizontal: 15),
                    child: Row(
                      children: [
                        Row(
                          children: [
                            Text(
                              '定位到: ',
                              style: TextStyle(
                                  color: MyColors.cFF4233, fontSize: 14),
                            ),
                            Text(
                              _address == null
                                  ? '北京市 北京市'
                                  : '${_address.currentProvince.province} ${_address.currentCity.city}',
                              style: TextStyle(
                                  color: MyColors.cFF4233, fontSize: 14),
                            ),
                          ],
                        ),
                        GestureDetector(
                          child: Container(
                            height: 40,
                            width: 60,
                            alignment: Alignment.center,
                            child: Text(
                              '确定',
                              style: TextStyle(
                                  color: MyColors.cFF4233, fontSize: 16),
                            ),
                          ),
                          onTap: () {
                            if (_address == null) {
                              province = '北京市';
                              city = '北京市';
                              setState(() {});
                              _reController.requestRefresh();
                              _address = null;
                              Navigator.pop(context);
                            } else {
                              province = _address.currentProvince.province;
                              city = _address.currentCity.city;
                              setState(() {});
                              _reController.requestRefresh();
                              _address = null;
                              Navigator.pop(context);
                            }
                          },
                          behavior: HitTestBehavior.translucent,
                        ),
                      ],
                      mainAxisAlignment: MainAxisAlignment.spaceBetween,
                    ),
                  );
                },
              ),
              GestureDetector(
                onTap: () {
                  if (MyCookie().location != null) {
                    province = MyCookie().location.province;
                    city = MyCookie().location.city;
                    setState(() {});
                    _reController.requestRefresh();
                    _address = null;
                    Navigator.pop(context);
                  }
                },
                behavior: HitTestBehavior.translucent,
                child: Container(
                  height: 60,
                  color: Colors.white,
                  padding: EdgeInsets.symmetric(horizontal: 20),
                  child: Row(
                    children: [
                      Text(
                        '当前定位:',
                        style: TextStyle(color: MyColors.c333333, fontSize: 16),
                      ),
                      Text(
                        MyCookie().location != null
                            ? '${MyCookie().location.province} ${MyCookie().location.city}'
                            : '请开启定位权限',
                        style: TextStyle(color: MyColors.c333333, fontSize: 16),
                      )
                    ],
                  ),
                ),
              ),
              Container(
                height: 250.0,
                child: AddressPicker(
                  style: TextStyle(color: Colors.black, fontSize: 17),
                  mode: AddressPickerMode.provinceAndCity,
                  onSelectedAddressChanged: (address) {
                    _address = address;
                    ss(() {});
                  },
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class _SliverAppBarDelegate extends SliverPersistentHeaderDelegate {
  _SliverAppBarDelegate({
    @required this.minHeight,
    @required this.maxHeight,
    @required this.child,
  });

  final double minHeight;
  final double maxHeight;
  final Widget child;

  @override
  double get minExtent => minHeight;

  @override
  double get maxExtent => max(maxHeight, minHeight);

  @override
  Widget build(
      BuildContext context, double shrinkOffset, bool overlapsContent) {
    return new SizedBox.expand(child: child);
  }

  @override
  bool shouldRebuild(_SliverAppBarDelegate oldDelegate) {
    return maxHeight != oldDelegate.maxHeight ||
        minHeight != oldDelegate.minHeight ||
        child != oldDelegate.child;
  }
}