Flutter facebook newsfeed refactoring with method (anti-pattern)

flutter_facebook_newsfeed.dart

import 'package:flutter/material.dart';

final Color darkBlue = Color.fromARGB(255, 18, 32, 47);

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.dark().copyWith(scaffoldBackgroundColor: darkBlue),
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: Center(
          child: FacebookNewsfeed(),
        ),
      ),
    );
  }
}

class FacebookNewsfeed extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    double screenHeight = MediaQuery.of(context).size.height;

    return Container(
      color: Colors.white,
      child: SafeArea(
        child: Stack(
          children: <Widget>[
            Column(
              children: <Widget>[
                // AppBar
                _buildAppBar(screenHeight, context),
                // Header
                _buildHeaderTabs(screenHeight),
                // Newsfeed
                _buildNewsfeedItems(screenHeight)
              ],
            ),
            // BottomAction
            _buildBottomActions(context, screenHeight)
          ],
        ),
      ),
    );
  }

  Expanded _buildNewsfeedItems(double screenHeight) {
    return Expanded(
      child: Container(
        padding: const EdgeInsets.all(16.0),
        color: Color.fromARGB(255, 242, 242, 242),
        child: ListView(
          children: <Widget>[
            Container(
              color: Colors.white,
              margin: const EdgeInsets.only(bottom: 16.0),
              child: Column(
                children: <Widget>[
                  Container(
                    height: screenHeight / 12,
                    padding: const EdgeInsets.all(8),
                    child: Row(
                      mainAxisSize: MainAxisSize.min,
                      children: <Widget>[
                        SizedBox(
                          width: 32.0,
                          height: 32.0,
                          child: Placeholder(),
                        ),
                        SizedBox(width: 8.0),
                        SizedBox(
                          width: 64.0,
                          height: 32.0,
                          child: Placeholder(),
                        ),
                        Spacer(),
                        SizedBox(
                          width: 32.0,
                          height: 32.0,
                          child: Placeholder(),
                        ),
                      ],
                    ),
                  ),
                  Container(
                    padding: const EdgeInsets.all(8),
                    height: screenHeight / 3,
                    child: Placeholder(),
                  ),
                  Container(
                    padding: const EdgeInsets.all(8),
                    height: screenHeight / 12,
                    child: Row(
                      mainAxisSize: MainAxisSize.min,
                      children: <Widget>[
                        Expanded(
                          child: Padding(
                            padding: const EdgeInsets.symmetric(
                                vertical: 8.0, horizontal: 16.0),
                            child: Placeholder(),
                          ),
                        ),
                        Expanded(
                          child: Padding(
                            padding: const EdgeInsets.symmetric(
                                vertical: 8.0, horizontal: 16.0),
                            child: Placeholder(),
                          ),
                        ),
                        Expanded(
                          child: Padding(
                            padding: const EdgeInsets.symmetric(
                                vertical: 8.0, horizontal: 16.0),
                            child: Placeholder(),
                          ),
                        ),
                      ],
                    ),
                  ),
                ],
              ),
            ),
            Container(
              color: Colors.white,
              margin: const EdgeInsets.only(bottom: 16.0),
              child: Column(
                children: <Widget>[
                  Container(
                    height: screenHeight / 12,
                    padding: const EdgeInsets.all(8),
                    child: Row(
                      mainAxisSize: MainAxisSize.min,
                      children: <Widget>[
                        SizedBox(
                          width: 32.0,
                          height: 32.0,
                          child: Placeholder(),
                        ),
                        SizedBox(width: 8.0),
                        SizedBox(
                          width: 64.0,
                          height: 32.0,
                          child: Placeholder(),
                        ),
                        Spacer(),
                        SizedBox(
                          width: 32.0,
                          height: 32.0,
                          child: Placeholder(),
                        ),
                      ],
                    ),
                  ),
                  Container(
                    padding: const EdgeInsets.all(8),
                    height: screenHeight / 3,
                    child: Placeholder(),
                  ),
                  Container(
                    padding: const EdgeInsets.all(8),
                    height: screenHeight / 12,
                    child: Row(
                      mainAxisSize: MainAxisSize.min,
                      children: <Widget>[
                        Expanded(
                          child: Padding(
                            padding: const EdgeInsets.symmetric(
                                vertical: 8.0, horizontal: 16.0),
                            child: Placeholder(),
                          ),
                        ),
                        Expanded(
                          child: Padding(
                            padding: const EdgeInsets.symmetric(
                                vertical: 8.0, horizontal: 16.0),
                            child: Placeholder(),
                          ),
                        ),
                        Expanded(
                          child: Padding(
                            padding: const EdgeInsets.symmetric(
                                vertical: 8.0, horizontal: 16.0),
                            child: Placeholder(),
                          ),
                        ),
                      ],
                    ),
                  ),
                ],
              ),
            )
          ],
        ),
      ),
    );
  }

  Container _buildHeaderTabs(double screenHeight) {
    return Container(
      height: screenHeight / 12,
      child: Row(
        children: <Widget>[
          Expanded(
            child: Container(
              decoration: BoxDecoration(
                border: Border(
                  bottom: BorderSide(
                    width: 4.0,
                    color: const Color.fromARGB(255, 59, 89, 152),
                  ),
                ),
              ),
              padding:
                  const EdgeInsets.symmetric(vertical: 8.0, horizontal: 16.0),
              child: Placeholder(
                color: Color.fromARGB(255, 59, 89, 152),
                strokeWidth: 4.0,
              ),
            ),
          ),
          Expanded(
            child: Container(
              decoration: BoxDecoration(
                border: Border(
                  bottom: BorderSide(
                    width: 4.0,
                    color: Colors.white,
                  ),
                ),
              ),
              padding:
                  const EdgeInsets.symmetric(vertical: 8.0, horizontal: 16.0),
              child: Placeholder(
                strokeWidth: 4.0,
              ),
            ),
          ),
          Expanded(
            child: Container(
              decoration: BoxDecoration(
                border: Border(
                  bottom: BorderSide(
                    width: 4.0,
                    color: Colors.white,
                  ),
                ),
              ),
              padding:
                  const EdgeInsets.symmetric(vertical: 8.0, horizontal: 16.0),
              child: Placeholder(
                strokeWidth: 4.0,
              ),
            ),
          ),
          Expanded(
            child: Container(
              decoration: BoxDecoration(
                border: Border(
                  bottom: BorderSide(
                    width: 4.0,
                    color: Colors.white,
                  ),
                ),
              ),
              padding:
                  const EdgeInsets.symmetric(vertical: 8.0, horizontal: 16.0),
              child: Placeholder(
                strokeWidth: 4.0,
              ),
            ),
          ),
          Expanded(
            child: Container(
              decoration: BoxDecoration(
                border: Border(
                  bottom: BorderSide(
                    width: 4.0,
                    color: Colors.white,
                  ),
                ),
              ),
              padding:
                  const EdgeInsets.symmetric(vertical: 8.0, horizontal: 16.0),
              child: Placeholder(
                strokeWidth: 4.0,
              ),
            ),
          ),
        ],
      ),
    );
  }

  Container _buildAppBar(double screenHeight, BuildContext context) {
    return Container(
      color: Color.fromARGB(255, 59, 89, 152),
      padding: EdgeInsets.symmetric(horizontal: 16.0),
      height: screenHeight / 12,
      child: Row(
        children: <Widget>[
          SizedBox(
            width: 32.0,
            height: 32.0,
            child: GestureDetector(
                behavior: HitTestBehavior.opaque,
                onTap: () {
                  Navigator.of(context).pop();
                },
                child: Placeholder(color: Colors.white)),
          ),
          SizedBox(width: 16.0),
          SizedBox(
              width: 128.0,
              height: 32.0,
              child: Placeholder(color: Colors.white)),
          Spacer(),
          SizedBox(
              width: 32.0,
              height: 32.0,
              child: Placeholder(color: Colors.white)),
          SizedBox(width: 16.0),
          SizedBox(
              width: 32.0,
              height: 32.0,
              child: Placeholder(color: Colors.white)),
        ],
      ),
    );
  }

  Positioned _buildBottomActions(BuildContext context, double screenHeight) {
    return Positioned(
      bottom: 0,
      left: 0,
      width: MediaQuery.of(context).size.width,
      child: Container(
        color: Color.fromARGB(225, 59, 89, 152),
        height: screenHeight / 12,
        child: Row(
          children: <Widget>[
            Expanded(
              child: Padding(
                padding:
                    const EdgeInsets.symmetric(vertical: 8.0, horizontal: 16.0),
                child: Placeholder(color: Colors.white),
              ),
            ),
            Expanded(
              child: Padding(
                padding:
                    const EdgeInsets.symmetric(vertical: 8.0, horizontal: 16.0),
                child: Placeholder(color: Colors.white),
              ),
            ),
            Expanded(
              child: Padding(
                padding:
                    const EdgeInsets.symmetric(vertical: 8.0, horizontal: 16.0),
                child: Placeholder(color: Colors.white),
              ),
            ),
          ],
        ),
      ),
    );
  }
}