appBar: new AppBar(

    actions: [

      new Padding(padding: const EdgeInsets.all(10.0),

        child: new Container(
          height: 150.0,
          width: 30.0,
          child: new GestureDetector(
            onTap: () {
              Navigator.of(context).push(
                  new MaterialPageRoute(
                      builder:(BuildContext context) =>
                      new CartItemsScreen()
                  )
              );
            },

            child: new Stack(

              children: [
                new IconButton(icon: new Icon(Icons.shopping_cart,
                  color: Colors.white,),
                    onPressed: null,
                ),
                list.length ==0 ? new Container() :
                new Positioned(

                    child: new Stack(
                      children: [
                        new Icon(
                            Icons.brightness_1,
                            size: 20.0, color: Colors.green[800]),
                        new Positioned(
                            top: 3.0,
                            right: 4.0,
                            child: new Center(
                              child: new Text(
                                list.length.toString(),
                                style: new TextStyle(
                                    color: Colors.white,
                                    fontSize: 11.0,
                                    fontWeight: FontWeight.w500
                                ),
                              ),
                            )),


                      ],
                    )),

              ],
            ),
          )
        )

        ,)],