When I Scroll the content of pages goes behind search bar and text widget

Question

My Widget Structure is as following

When the Main PageView index is 0 then Explore() Widget is called, else Category() widget is called

Align(
  alignment: Alignment.center,
  child: PageView.builder(
    controller: _controller,
    onPageChanged: (val) {
      setState(() {
        currentIndex = val;
      });
    },
    itemCount: 2,
    itemBuilder: (context, index) {
      return index == 0 ? Explore() : CategoryWrapper();
    },
  ),
),

Inside Explore() Widget I have a screenshot of the widget tree

Widget tree of the explore widget

My issue is whenever I scroll in explore page the content hide inside the search bar, can anyone please help me to figure the problem.

Screenshot of the page when it loads

Screenshot of the page when you scroll