How to make a floating widget just below AppBar in flutter

I am trying to implement the below design with Flutter.

I could manage to do that by following the code sample.

Scaffold(
    drawer: const NavDrawer(), // drawer widget
    appBar: AppBar(
      actions: <Widget>[
        IconButton(
          icon: const Icon(Icons.notifications),
          onPressed: () {
            //...
          },
        ),
        IconButton(
          icon: const Icon(Icons.filter_alt),
          onPressed: () {
            //...
          },
        ),
      ],
    ),
    body: Column(
      children: [
        const CommonSearchBar(), // common search bar widget.
        Expanded(
          child: NestedScrollView(
            floatHeaderSlivers: true,
            headerSliverBuilder: (context, value) {
              return [
                SliverList(
                  delegate: SliverChildListDelegate.fixed(
                    [
                      ClipRRect(
                        borderRadius: BorderRadius.circular(20.0),
                        child: Image.asset(
                            'assets/images/valentine_image.png'),
                      ),
                    ],
                  ),
                ),
              ];
            },
            body: GridView.builder(
                gridDelegate:
                    const SliverGridDelegateWithFixedCrossAxisCount(
                  crossAxisCount: 2,
                ),
                itemCount: 100,
                itemBuilder: (BuildContext context, int index) {
                  return Card(
                    color: Colors.amber,
                    child: Center(child: Text('$index')),
                  );
                }),
          ),
        ),
      ],
    ),
  ),

here Search bar needs to stay on the screen and the rest of the part needs to scroll while scrolling.

but I am very new to Flutter and I need to know if is this the better approach to do this.

If not please help me to implement this in a better way.

thank you.

For your requirement you should try with dependency and without dependency.

Without dependency - Sliver App Bar

With dependency :- Sticky Header

You can do it easier with a SliverAppBar

You don't have to use the scaffold appBar property, just add a SliverAppBar to the headerSlivers.
In the SliverAppBar you can add a bottom widget what will stay on top with the app bar, you can add the action buttons and title to it.

A minimal example:

Scaffold(
  body: NestedScrollView(
    headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
      return [
        SliverAppBar(
          title: Text("Title"),
          floating: false,
          snap: false,
          pinned: true,
          actions: [
            IconButton(
              icon: const Icon(Icons.notifications),
              onPressed: () {
                //...
              },
            ),
            IconButton(
              icon: const Icon(Icons.filter_alt),
              onPressed: () {
                //...
              },
            ),
          ],
          bottom: PreferredSize(
            preferredSize: Size(double.infinity, 50),
            child: Text("Search")
          ),
        )
      ];
    },
    body: ListView.builder(
        itemCount: 200,
        itemBuilder: (context, index) {
          return Text("$index item");
        },
    ),
  )
);