CustomScrollView(

              slivers:[

                SliverList(

                  delegate: SliverChildBuilderDelegate((context, int index){

                    Container postPiece;

                    if (index == 0){

                      postPiece = Container(

                        child: Text('$index , aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa', style: TextStyle(color: Colors.grey),),

                      );

                    } else {

                      postPiece = Container(

                        child: Text('$index, bbbbbbbbbbbbb', style: TextStyle(color: Colors.black),),

                      );

                    }

                    return postPiece;

                  },

                    childCount: 100,

                  ),

                ),

//                SliverFixedExtentList(

//                  itemExtent: 50, //child的长度或者宽度,取决于滚动方向.

//                  delegate: SliverChildBuilderDelegate((context, int index) {

//                    print(content.mainPost);

//                    Container _piece;

//                    if (index == 0){

//                      _piece = Container(

//                        child: Text('dsssouu',style: TextStyle(color: Colors.black),),

//                      );

//                    }else{

//                      _piece = Container(

//                        child: Text('aaaa', style: TextStyle(color: Colors.grey),),

//                      );

//                    }

//                    return _piece;

//                  },

//                    childCount: 20,

//                  ),

//                ),

            ],

            ),