samples/material_studies/shrine/lib/supplemental/product_columns.dart

// Copyright 2018-present the Flutter authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import 'package:flutter/material.dart';

import '../model/product.dart';
import 'product_card.dart';

class TwoProductCardColumn extends StatelessWidget {
  TwoProductCardColumn({
    this.bottom,
    this.top,
  }) : assert(bottom != null);

  final Product bottom, top;

  @override
  Widget build(BuildContext context) {
    return LayoutBuilder(
      builder: (context, constraints) {
        const spacerHeight = 44.0;

        double heightOfCards =
            (constraints.biggest.height - spacerHeight) / 2.0;
        double heightOfImages = heightOfCards - ProductCard.kTextBoxHeight;
        double imageAspectRatio = (heightOfImages >= 0.0 &&
                constraints.biggest.width > heightOfImages)
            ? constraints.biggest.width / heightOfImages
            : 33 / 49;

        return ListView(
          children: <Widget>[
            Padding(
              padding: EdgeInsetsDirectional.only(start: 28.0),
              child: top != null
                  ? ProductCard(
                      imageAspectRatio: imageAspectRatio,
                      product: top,
                    )
                  : SizedBox(
                      height: heightOfCards > 0 ? heightOfCards : spacerHeight,
                    ),
            ),
            SizedBox(height: spacerHeight),
            Padding(
              padding: EdgeInsetsDirectional.only(end: 28.0),
              child: ProductCard(
                imageAspectRatio: imageAspectRatio,
                product: bottom,
              ),
            ),
          ],
        );
      },
    );
  }
}

class OneProductCardColumn extends StatelessWidget {
  OneProductCardColumn({this.product});

  final Product product;

  @override
  Widget build(BuildContext context) {
    return ListView(
      reverse: true,
      children: <Widget>[
        SizedBox(
          height: 40.0,
        ),
        ProductCard(
          product: product,
        ),
      ],
    );
  }
}