how to create This type of appbar in flutter

Question

Please give some code regarding this image

Answer 1

You can try this SliverPersistentHeaderDelegate. Play with shrinkOffset. I thought It might be easier with CupertinoSliverNavigationBar but it needed to maintain height for multiline.

class AppSliverPersistentHeader extends SliverPersistentHeaderDelegate {
  @override
  Widget build(
      BuildContext context, double shrinkOffset, bool overlapsContent) {
    return Stack(
      children: [
        Align(
          alignment: Alignment.lerp(const Alignment(-1, 0),
              const Alignment(0, 0), (shrinkOffset / maxExtent))!,
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              Text("Text A"),
              Text("Text B"),
            ],
          ),
        )
      ],
    );
  }

  @override
  double get maxExtent => 120;

  @override
  double get minExtent => kToolbarHeight;

  @override
  bool shouldRebuild(covariant SliverPersistentHeaderDelegate oldDelegate) {
    return false;
  }
}

And test snippet

class AppBarTest extends StatelessWidget {
  const AppBarTest({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: CustomScrollView(
        slivers: [
          // CupertinoSliverNavigationBar(
          //   largeTitle: Column(
          //     children: [
          //       Text.rich(TextSpan(text: "MyContaint", children: [
          //         TextSpan(
          //             text: "\nothers",
          //             style: TextStyle(
          //               fontSize: 12,
          //             ))
          //       ])),
          //     ],
          //   ),
          // ),
          SliverPersistentHeader(
            pinned: true,
            delegate: AppSliverPersistentHeader(),
          ),
          SliverToBoxAdapter(
            child: Container(
              height: 3333,
            ),
          ),
        ],
      ),
    );
  }
}

You can choose two stack items instead of one column.