To Show/Hide AppBar on scroll in Flutter use a SliverAppBar to create a Flutter collapsing toolbar animation.
Source Code | https://github.com/JohannesMilke/hide_appbar_example

TIMELINE
0:00 Introduction Show/Hide AppBar On Scroll
0:39 Hide AppBar On Scroll / Collapsable Toolbar
1:07 Floating SliverAppBar
1:48 Snapping Animation For SliverAppBar
2:23 When Scrolling Stopped Snap SliverAppBar
2:58 How Works FloatHeaderSlivers?
3:31 Pinned TabBar / Scrollable TabBar
5:02 Fix Overlapping In TabBar And SliverAppBar
7:31 Scrollable AppBar With Increasing Elevation

#flutter