Stack below the AppBar and not behind

Question

I cant seem to find the answer to this simple problem but I dont understand why my Stack is BELOW the appbar and not BEHIND it. Also, this is a custom appbar

What Im trying to achieve: The image should be BEHIND the appbar and not below it, meaning the appbar will overlap the image or is in front of the image

my code for this is this:

Widget build(BuildContext context) {
    return SafeArea(
          child: Scaffold(
        extendBodyBehindAppBar: true,
        appBar: AppBar(
          elevation: 1,
          backgroundColor: Colors.transparent,
        ),
        body: ListView(
          children: <Widget>[
            Stack(
              children: <Widget>[
                Hero(
                  tag: widget.discount.name,
                  child: ShadowClip(
                    clipper: CircularClipper(),
                    shadow: Shadow(blurRadius: 0.0),
                    child: FadeInImage.assetNetwork(
                      placeholder: 'assets/images/placeholder.png',
                      height: 200.0,
                      width: double.infinity,
                      fit: BoxFit.cover,
                      image: widget.discount.imageUrl.Url,
                    ),
                  ),
                ),
              // Positioned(
              //   top: 0, left: 0, right: 0, bottom: 0,
              //   child: DetailPageAppbar(height:60),
              // ),
              ],
            ),

Answer 1

Please try below code and check output

  SafeArea(
        child: Scaffold(
      extendBodyBehindAppBar: true,
      appBar: AppBar(
        elevation: 1,
        leading: Icon(Icons.arrow_back_ios),
        backgroundColor: Colors.transparent,
      ),
      body: Stack(
        children: <Widget>[
          Column(
            children: <Widget>[
              Flexible(
                flex: 3,
                child: Container(
                    width: MediaQuery.of(context).size.width,
                    decoration: BoxDecoration(
                        image: DecorationImage(
                            fit: BoxFit.cover,
                            image: NetworkImage(
                                "https://picsum.photos/250?image=9")))),
              ),
              Flexible(
                flex: 6,
                child: ListView.builder(
                  itemCount: 50,
                  itemBuilder: (BuildContext context, int pos) {
                    return ListTile(
                      title: Text("121"),
                    );
                  },
                ),
              )
            ],
          )
        ],
      ),
    ));

Answer 2

Do this:

Widget build(BuildContext context) {
    return SafeArea(
          child: Scaffold(
        extendBodyBehindAppBar: true,
        appBar: Header(),
        //...
     }   //end method build

PreferredSize Header() {
   return PreferredSize(
     preferredSize: Size.fromHeight(56.0),    //default appbar height (material design principles)
     child: Container(
        color: Colors.Transparent,
        child: Center(
          child: Text("APPBAR TEXT"),
        ), 
      ),
   );

}  //end method Header