How to set container in stack in Flutter

Question

I have created a simple app, and facing an issue. I just want the content a little bit over the bottom of the image. but can't set position to container.

gets error 'size.isFinite': is not true."

1. Image should be in full width.
2. container over the bottom of the image.
3. Button should be tappable, when button is in overflowed, can't access tap events.

how to do that?

import 'package:flutter/material.dart';

class StackButtonCheck extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('appbar'),
      ),
      body: SingleChildScrollView(
        child: Column(
          children: [
            Text('code'),
            Text('code to check'),
            Stack(
              clipBehavior: Clip.none,
              children: [
                Positioned(
                  //top: 50,
                  left: 0,
                  right: 0,
                  bottom: 50,
                  child: Image.network(
                    'https://cdn.pixabay.com/photo/2017/08/30/01/05/milky-way-2695569_1280.jpg',
                    fit: BoxFit.fitWidth,
                    // height: 130,
                    //width: 1000,
                  ),
                ),
                Positioned(
                  //top: 100,
                  // left: 0,
                  // right: 0,
                  //top: 5,
                  child: Container(
                    margin: EdgeInsets.all(8),
                    decoration: BoxDecoration(
                      color: Colors.white,
                      borderRadius: BorderRadius.circular(20),
                    ),
                    child: Column(
                      children: [
                        Text('content should display'),
                        ElevatedButton(
                          onPressed: () {
                            print('button event occus');
                          },
                          child: Text('tap should work'),
                        ),
                        Text('''Lorem Ipsum is simply dummy text of the printing
         and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.'''),
                      ],
                    ),
                  ),
                )
              ],
            )
          ],
        ),
      ),
    );
  }
}

class StackButtonCheck extends StatelessWidget {
  const StackButtonCheck({Key key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('appbar'),
      ),
      body: SingleChildScrollView(
        child: Column(
          children: [
            LayoutBuilder(
              builder: (context, constraints) => Stack(
                children: [
                  Positioned(
                    bottom: 50,
                    child: Image.network(
                      'https://cdn.pixabay.com/photo/2017/08/30/01/05/milky-way-2695569_1280.jpg',
                      fit: BoxFit.fitWidth,
                      // height: 130,
                      height: constraints.maxHeight - 50,
                      width: constraints.maxWidth,
                    ),
                  ),
                  Positioned(
                    bottom: 30, // end must be 10px above
                    child: SingleChildScrollView(
                      child: Container(
                        width: constraints.maxWidth,
                        padding: EdgeInsets.all(8),
                        decoration: BoxDecoration(
                          color: Colors.white,
                          borderRadius: BorderRadius.circular(20),
                        ),
                        child: Column(
                          mainAxisSize: MainAxisSize.min,
                          children: [
                            Text('content should display'),
                            ElevatedButton(
                              onPressed: () {
                                print('button event occus');
                              },
                              child: Text('tap should work'),
                            ),
                            text(),
                          ],
                        ),
                      ),
                    ),
                  )
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }

  Text text() {
    return Text('''Lorem Ipsum is simply dummy text of the printing
       and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.''');
  }
}

The code works fine without first SingleChildScrollView and Column.
But I want with SingleChildScrollView and Column because I need to put other widgets.

Answer 1

Just add Expanded Widget to fill the screen height and move SingleChildScrollWidget and Expanded to the long Text:

import 'package:flutter/material.dart';

class TestPage extends StatelessWidget {
  const TestPage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('appbar'),
      ),
      body: Column(
        children: [
          const Text('code'),
          const Text('code to check'),
          Expanded(
            child: Stack(
              clipBehavior: Clip.none,
              children: [
                Positioned(
                  top: 0,
                  left: 0,
                  right: 0,
                  bottom: 0,
                  child: Image.network(
                    'https://cdn.pixabay.com/photo/2017/08/30/01/05/milky-way-2695569_1280.jpg',
                    fit: BoxFit.fill,
                    // height: 130,
                    //width: 1000,
                  ),
                ),
                Positioned(
                  //top: 100,
                  // left: 0,
                  // right: 0,
                  //top: 5,
                  child: Container(
                    margin: const EdgeInsets.all(8),
                    decoration: BoxDecoration(
                      color: Colors.white,
                      borderRadius: BorderRadius.circular(20),
                    ),
                    child: Column(
                      children: [
                        const Text('content should display'),
                        ElevatedButton(
                          onPressed: () {
                            print('button event occus');
                          },
                          child: const Text('tap should work'),
                        ),
                        Expanded(
                          child: const SingleChildScrollView(
                            child: Text(
                                '''Lorem Ipsum is simply dummy text of the printing
                                             and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.'''),
                          ),
                        ),
                      ],
                    ),
                  ),
                )
              ],
            ),
          )
        ],
      ),
    );
  }
}

Answer 2

While the image will be fixed on background, you can wrap others on scrollable widget,

class StackButtonCheck extends StatelessWidget {
  const StackButtonCheck({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('appbar'),
      ),
      body: LayoutBuilder(
        builder: (context, constraints) => Stack(
          children: [
            Positioned(
              bottom: 50,
              child: Image.network(
                'https://cdn.pixabay.com/photo/2017/08/30/01/05/milky-way-2695569_1280.jpg',
                fit: BoxFit.fitWidth,
                // height: 130,
                height: constraints.maxHeight - 50,
                width: constraints.maxWidth,
              ),
            ),
            Positioned(
              bottom: 10, // end must be 10px above
              child: SingleChildScrollView(
                child: Container(
                  width: constraints.maxWidth,
                  padding: EdgeInsets.all(8),
                  decoration: BoxDecoration(
                    color: Colors.white,
                    borderRadius: BorderRadius.circular(20),
                  ),
                  child: Column(
                    mainAxisSize: MainAxisSize.min,
                    children: [
                      Text('content should display'),
                      ElevatedButton(
                        onPressed: () {
                          print('button event occus');
                        },
                        child: Text('tap should work'),
                      ),
                      text(),
                    ],
                  ),
                ),
              ),
            )
          ],
        ),
      ),
    );
  }

  Text text() {
    return Text('''Lorem Ipsum is simply dummy text of the printing
       and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.''');
  }
}