flutter 上滑悬浮吸顶_flutter滑动吸顶

使用 ：RefreshIndicator+NestedScrollView+(TabBar、TabView)+SmartRefresher打造可下拉刷新和上拉加载的tab吸顶效果。

1.导入

pull_to_refresh: ^2.0.0
flutter_swiper: ^1.1.6

2.RefreshIndicator+NestedScrollView

class ListPage extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => _ListPageState();
}

class _ListPageState extends State<ListPage>
    with AutomaticKeepAliveClientMixin ,TickerProviderStateMixin{

  /// 轮播图
  List<BannerModel> bannerList = [];

  SwiperController _swiperController;

  List<GoodsListModel> goodsList = [];

  int pageNum = 1;

  int _position  = 0;

  List<GoodsCategoryBean> _goodsCategoryList = [];
  TabController _tabController;
  bool _isFirstIn = true;

  @override
  void initState() {
    super.initState();
    _swiperController = SwiperController();
    _swiperController.startAutoplay();
    if(_isFirstIn){
      _isFirstIn = false;
    }
    getData();
  }

  @override
  void dispose() {
    _swiperController.stopAutoplay();
    _swiperController.dispose();
    _tabController.dispose();

    super.dispose();
  }
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: CustomAppBar(
        backgroundColor: Colors.white,
        elevation: 0,
        leading: GestureDetector(
          onTap: () {
            Navigator.pop(context);
          },
          child: Icon(Icons.arrow_back_ios),
        ),
        iconTheme: IconThemeData(color: Color(0xff999999)),
        title: Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: [
            Container(),
            Container(
              margin: EdgeInsets.only(right: setWidth(34)),
              child: Text(
                S.current.remenshangpin,
                style: TextStyle(color: Colors.black),
              ),
            ),
            GestureDetector(
              onTap: () {
                esLoadingToast('去搜索');
              },
              child: Image.asset(
                PathConfig.imageSearch,
                fit: BoxFit.cover,
                width: 40.w,
                height: 40.w,
                color: HexColor('#999999'),
              ),
            )
          ],
        ),
        centerTitle: true,
      ),
      body: RefreshIndicator(
        notificationPredicate: (notifation) {
          // 返回true即可,避免下拉刷新时和NestedScrollView滑动冲突
          return true;
        },
        child:NestedScrollView(
          headerSliverBuilder: (BuildContext context,bool b){
            return [initSliverPersistentHeader(),initSliverPersistentHeaderTwo()];
          },
          body: _goodsListView(),
        ), onRefresh: (){
        pageNum = 1;
        getData();
        return Future.value(true);
      },
      ),
    );
  }
  //轮播
  _swiperView(){
    return Container(
      child: Swiper(
        itemCount: bannerList?.length ?? 0,
        loop: false,
        autoplay: false,
        controller: _swiperController,
        itemBuilder: (BuildContext context, int index) {
          return GestureDetector(
              onTap: () {
                BannerModel banner = bannerList[index];
                if (banner.inner) {
                  if (banner.itemType == 1) {
                    NavigatorUtil.push(GoodsDetail(
                      goodsId: '${banner.itemId}',
                    ));
                  } else if (banner.itemType == 4) {
                    VideoUtil.viewVideoDetail(context, banner.itemId);
                  } else if (banner.itemType == 2) {
                    CinemaUtil.viewCinemaDetail(
                        context, banner.itemId, null);
                  } else if (banner.itemType == 3) {
                    NavigatorUtil.push(LifeServiceDetail(
                      itemId: int.parse('${banner.itemId}'),
                    ));
                  }
                } else {
                  NavigatorUtil.push(
                      ViewMain(url: banner.redirectLink));
                }
              },
              child: CachedNetworkImage(
                imageUrl: bannerList[index].banner,
                fit: BoxFit.fill,
              ));
        },
        pagination: SwiperPagination(
          builder: DotSwiperPaginationBuilder(
              color: Colors.white.withAlpha(80),
              activeColor: Colors.white),
        ),
      ),
    );
  }
  //商品类别tab
  _goodsTabBar() {
    if(_goodsCategoryList.isNotEmpty){
      return TabBar(
        controller: _tabController,
        // tabs的长度超出屏幕宽度后，TabBar，是否可滚动
        isScrollable: true,
        // 设置tab文字的类型
        labelStyle: TextStyle(
            fontSize: 15, letterSpacing: 1, fontWeight: FontWeight.w600),
        // 设置tab选中得颜色
        labelColor: JadeColors().claret,
        // 设置tab未选中的颜色
        unselectedLabelColor: JadeColors().grey,
        // 设置tab未选中时文字的类型
        unselectedLabelStyle: TextStyle(fontSize: 15, letterSpacing: 1),
        indicatorWeight: 0.01,
        indicatorColor: Colors.transparent,
        tabs: _goodsCategoryList
            .map((value) => Tab(
          text: value.name,
        )).toList(),
      );
    }else{
      return Container();
    }
  }

  _goodsListView() {
    if(_goodsCategoryList.isNotEmpty){
      return TabBarView(
        controller: _tabController,
        children: _tabViews(),
      );
    }else{
      return Container();
    }
  }

  _tabViews(){
    List<Widget> _tabViewList = [];
    for(int i = 0;i<_goodsCategoryList.length;i++){
      _tabViewList.add(GoodsListPage(categoryParams: _goodsCategoryList[i],index: i,key: Key('$i'),));//传入类别数组的index,
    }
    return _tabViewList;
  }

  void getData() {
    Future.delayed(Duration(seconds: 1), () {
     // 接口请求
 1.banner请求
 2.tabBar数据请求
_httpGoodsCategory();
    });
  }
//商品类别
  _httpGoodsCategory(){
    HttpApplication.getInstance().goodsCategoryList(callBack: (result){
      if(result!=null){
        if(mounted){
          List<GoodsCategoryBean> _dataList = [];
          for(int i = 0; i< result.length; i++){
            GoodsCategoryBean _goodsCategoryBean = GoodsCategoryBean.fromJson(result[i]);
            if(_goodsCategoryBean.parentId == 0){
              _dataList.add(_goodsCategoryBean);
            }
          }
          _goodsCategoryList = _dataList;
          if(_goodsCategoryList.isNotEmpty){
            _tabController = TabController(length: _goodsCategoryList.length, vsync: this);
            _tabController.addListener(() {
              _position = _tabController.index;
            });
            _tabController.index = _position; //保持刷新时，tabBar index不会置为0
          }
          if(!_isFirstIn){
            ATuiEventBusTool.shared().fire({"type":"reset_page_num","viewIndex": _position});
          }
        }
        setState(() {});
        }

    },errorCallBack: (error){
      setState(() {});
    });
  }

  initSliverPersistentHeader() {
    return SliverPersistentHeader(
      //是否固定头布局 默认false
        pinned: false,
        //是否浮动 默认false
        floating: false,
        //必传参数,头布局内容
        delegate: MySliverDelegate(
          //缩小后的布局高度
          minHeight: 40.0,
          //展开后的高度
          maxHeight: Utils().screenWidth(context) * 0.6,
          child: Container(
              color: Colors.white,
              child: _swiperView()),
        ));
  }

  initSliverPersistentHeaderTwo() {
    return SliverPersistentHeader(
      //是否固定头布局 默认false
        pinned: true,
        //是否浮动 默认false
        floating: false,
        //必传参数,头布局内容
        delegate: MySliverDelegate(
          //缩小后的布局高度
          minHeight: 56.0,
          //展开后的高度
          maxHeight: 56.0,
          child: Container(
              color: Colors.white,
              child: _goodsTabBar()),
        ));
  }
  @override
  bool get wantKeepAlive => true;
}

class MySliverDelegate extends SliverPersistentHeaderDelegate {
  MySliverDelegate({
    @required this.minHeight,
    @required this.maxHeight,
    @required this.child,
  });
  final double minHeight; //最小高度
  final double maxHeight; //最大高度
  final Widget child; //子Widget布局

  @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 //是否需要重建
  bool shouldRebuild(MySliverDelegate oldDelegate) {
    return maxHeight != oldDelegate.maxHeight ||
        minHeight != oldDelegate.minHeight ||
        child != oldDelegate.child;
  }
}
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2.tabView中子页面GoodsListPage

class GoodsListPage extends StatefulWidget{
  final GoodsCategoryBean categoryParams;
  final physics;
  final index;
  final Key key;
  GoodsListPage({this.categoryParams,this.physics,this.index,this.key}):super(key:key);

  @override
  State<StatefulWidget> createState() {
    // TODO: implement createState
    return _GoodsListPage();
  }
}

class _GoodsListPage extends State<GoodsListPage>{

  List<GoodsListModel> _goodsList = [];
  int _page = 1;
  int _pageSize = 20;

  int _viewIndex = 0;
  var _loadType;
  RefreshController refreshController;
  @override
  void initState() {
    // TODO: implement initState
    super.initState();
    refreshController = RefreshController();
    _refreshHttp();

	//判断创建时传入的index,是否和通过EvenBus通知过来的tabController.index相等
	//相等则请求接口（只让当前页请求接口，防止每个子页面都请求）
    ATuiEventBusTool.shared().on().listen((event) {
      _viewIndex = event["viewIndex"];
      _loadType = event["type"];
      if(_loadType=="reset_page_num" && _viewIndex ==widget.index){
      _refreshHttp();
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return SmartRefresher(
      footer: defaultRefreshFooter(),
      controller:refreshController,
      enablePullDown: false,//禁止下拉刷新，防止与主页面冲突
      enablePullUp: true,
      onLoading: ()async{
        _loadMoreHttp();
      },
      child: CustomizeStaggeredGridView.countBuilder(
        crossAxisCount: 4,
        staggeredTileBuilder: (int index) => StaggeredTile.fit(2),
        mainAxisSpacing: 4.0,
        crossAxisSpacing: 4.0,
        itemCount: math.max(0, _goodsList.length * 2 - 1),
        shrinkWrap: true,
        //physics: physics,
        itemBuilder: (_, index) {
          GoodsListModel info = _goodsList[index];
          return GoodsItem(
            index: index,
            item: info,
          );
        },
        separatorBuilder: (_, __) => Container(),
      ),
    );
  }

  _httpGoodsList(){
    var params = {
      "goodsCategoryParentId": widget.categoryParams.id,
      "pageNum": _page,
      "pageSize": _pageSize, //默认20条
      "sort": 1
    };
    HttpApplication.getInstance().goodsList(params,callBack: (result){
      if(result != null){
        if(mounted){
          List<GoodsListModel> _resultList = [];
          var dataList = result['list'];
          for(int i = 0; i< dataList.length; i++){
            GoodsListModel _goodsListModel = GoodsListModel.fromJson(dataList[i]);
            _resultList.add(_goodsListModel);
          }
          if(_page == 1){
            _goodsList = _resultList;
            setState(() {});
          }else{
            _goodsList.addAll(_resultList);
            setState(() {});

            Future.delayed(Duration(microseconds: 500),(){
              if(_resultList.length < _pageSize){
                //没有更多数据
                if (refreshController.isLoading) {
                  refreshController.loadNoData();
                }
              }else{
                if (refreshController.isLoading) {
                  refreshController.loadComplete();
                }
              }
            });
          }
        }
        }
    },errorCallBack: (error){
      setState(() {});
    });
  }

  _refreshHttp(){
    _page = 1;
    _httpGoodsList();
  }
  _loadMoreHttp(){
    _page ++;
    _httpGoodsList();
  }
}
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