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,
//                  ),
//                ),],),