Flutter: search bar overflowed by 38 pixels on the bottom

Question

I'm implementing a SearchBar using flappy_search_bar, and I want to shrink it from the bottom so that it would fit to the appBar, because currently I get an error (also see screenshot below):

A RenderFlex overflowed by 38 pixels on the bottom.

I tried wrapping it with various widgets, yet it yielded nothing. How can I make the SearchBar thinner so that it would fit nicely in the appBar?

my code:

import 'package:flappy_search_bar/search_bar_style.dart';
import 'package:flappy_search_bar/flappy_search_bar.dart';
import 'package:flutter/material.dart';

class Post {
  final String title;
  final String description;

  Post(this.title, this.description);
}

Future<List<Post>> search(String search) async {
  await Future.delayed(Duration(seconds: 2));
  return List.generate(search.length, (int index) {
    return Post(
      "Title : $search $index",
      "Description :$search $index",
    );
  });
}

@override
Widget build(BuildContext context) {
  return Material(
    child: Scaffold(
    resizeToAvoidBottomInset: true,
      resizeToAvoidBottomPadding: false,
      backgroundColor: Colors.transparent,
      appBar: AppBar(
        elevation: 0.0,
         backgroundColor: Colors.lightGreen[800],
         actions: <Widget>[
         Expanded(
           child: Padding(
           padding: const EdgeInsets.only(
             left: 50,
             right: 5,
             bottom: 10,
             top: 4,
           ),
           child: SearchBar<Post>(
             searchBarStyle: SearchBarStyle(
               backgroundColor: Colors.white60,
               borderRadius: BorderRadius.circular(30),
             ),
             onSearch: search,
             onItemFound: (Post post, int index) {
               return ListTile(
                 title: Text(post.title),
                 subtitle: Text(post.description),
                );
               },
             ),
           ),
         ),
          IconButton(
            icon: Icon(Icons.shopping_cart_outlined),
             onPressed: null
          ),
          IconButton(
            icon: Icon(Icons.favorite),
            onPressed: null
          ),
        ],
        leading: IconButton(
           icon: Icon(Icons.logout)
            onPressed: null
        ),
      ),
    body: Center(CircularProgressIndicator())
    ),  
  );
}

Screenshot of current app's state:

Answer 1

As we can see from the flappy_search_bar source files, the height parameter is an hard-coded value that equals to 80.

Therefore, we could modify the height of the AppBar to solve the issue:

class CustomAppBar extends PreferredSize {
  CustomAppBar({Key key, Widget title, List<Widget> actions}) : super(
    key: key,
    preferredSize: Size.fromHeight(90),
    child: AppBar(
      title: title,
      elevation: 0.0,
      backgroundColor: Colors.lightGreen[800],
      actions: actions,
    ),
  );
}

And use it in our code:

@override
Widget build(BuildContext context) {
  return Material(
    child: Scaffold(
       resizeToAvoidBottomInset: true,
       resizeToAvoidBottomPadding: false,
       backgroundColor: Colors.transparent,
       appBar: CustomAppBar(actions: _appBarActions)
     )
  );
}