Tweet thumbnail with media

tweet_thumbnail_with_media.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: SingleChildScrollView(
          child: Column(
            children: [
              ListTile(
                leading: CircleAvatar(),
                dense: true,
                title: Text("Leslie Arkorful"),
                subtitle: Text("@lesliearkorful"),
              ),
              Container(
                height: 300,
                padding: EdgeInsets.symmetric(horizontal: 16, vertical: 10),
                child: ThumbnailGrid(
                  images: [
                    "image1",
                    "image2",
                    "image3",
                    "image4",
                  ],
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class ThumbnailGrid extends StatelessWidget {
  final List<String> images;
  final double spacing;
  const ThumbnailGrid({Key key, this.images = const [], this.spacing = 5.0}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    if (images?.isEmpty ?? true) return SizedBox();
    return ClipRRect(
      borderRadius: BorderRadius.circular(8),
      child: Row(
        mainAxisSize: MainAxisSize.max,
        children: [
          if (images.length == 1) ImageThumbnail(imageUrl: images[0]),
          if (images.length == 2) ...[
            ImageThumbnail(imageUrl: images[0]),
            SizedBox(width: spacing),
            ImageThumbnail(imageUrl: images[1]),
          ],
          if (images.length == 3) ...[
            ImageThumbnail(imageUrl: images[0]),
            SizedBox(width: spacing),
            Expanded(
              child: Column(
                children: [
                  ImageThumbnail(imageUrl: images[1]),
                  SizedBox(height: spacing),
                  ImageThumbnail(imageUrl: images[2]),
                ],
              ),
            ),
          ],
          if (images.length == 4) ...[
            Expanded(
              child: Column(
                children: [
                  ImageThumbnail(imageUrl: images[0]),
                  SizedBox(height: spacing),
                  ImageThumbnail(imageUrl: images[2]),
                ],
              ),
            ),
            SizedBox(width: spacing),
            Expanded(
              child: Column(
                children: [
                  ImageThumbnail(imageUrl: images[1]),
                  SizedBox(height: spacing),
                  ImageThumbnail(imageUrl: images[3]),
                ],
              ),
            ),
          ],
        ],
      ),
    );
  }
}

class ImageThumbnail extends StatelessWidget {
  final String imageUrl;
  final Function(String imageUrl) onTap;
  const ImageThumbnail({Key key, this.imageUrl, this.onTap}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Expanded(
      child: GestureDetector(
        onTap: () {
          if ((onTap != null) && (imageUrl != null)) onTap(imageUrl);
        },
        child: Container(
          decoration: BoxDecoration(color: Colors.blueGrey.shade200),
        ),
      ),
    );
  }
}