Question 128160 in Android Studio Question posted in
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Android Studio – SizedBox or Container in Flutter Dart

I have just started my coding journey in Flutter(Dart). I am trying to design a UI and I have succeeded a little bit but not to my inner peace 😛

So, actually I am trying to design a card like structure in which when I click/tap on it, it should expand and show more data and a button.

Eventually I succeeded using a boolean variable named isExpanded to make changes in height when clicked. But when I tap the container again (Inkwell feature) it shows render flex problem.

So, I want some help from you people, I am just newbie in this, when I get good knowledge, I promise that I will help others too.

So, I need these designs

The design I need

The design when it is clicked, it should expand and when clicked again it shouldn’t show render flex error

The design which I have somehow created lol 😛

Please, give some suggestions or even the code for the required layout, I will be glad for your help

Thank you

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2

Answers


  1. 0

    You can’t use SizedBox or container for this.

    SizedBox is mainly used to give size between widges

    Container widgets are mainly used as a parent widges where you can implement differnt propertys like color, border radius,… for the child widgets

    What you have to do is:-

    This can be achived in many ways like using animations and all…

    But, I Prefer you to check is ExpansionPanel

    Here, you can expand your card when on tap.

    When using ExpansionPanel you must use ExpansionPanelList

    So, you can make a list of ExpansionPanel.

    Try this code:-

    import 'package:flutter/material.dart';

void main() => runApp(const MyApp());

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

  static const String _title = 'Flutter Code Sample';

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: _title,
      home: Scaffold(
        appBar: AppBar(title: const Text(_title)),
        body: const MyStatefulWidget(),
      ),
    );
  }
}

// stores ExpansionPanel state information
class Item {
  Item({
    required this.expandedValue,
    required this.headerValue,
    this.isExpanded = false,
  });

  String expandedValue;
  String headerValue;
  bool isExpanded;
}

List<Item> generateItems(int numberOfItems) {
  return List<Item>.generate(numberOfItems, (int index) {
    return Item(
      headerValue: 'Panel $index',
      expandedValue: 'This is item number $index',
    );
  });
}

class MyStatefulWidget extends StatefulWidget {
  const MyStatefulWidget({Key? key}) : super(key: key);

  @override
  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
}

class _MyStatefulWidgetState extends State<MyStatefulWidget> {
  final List<Item> _data = generateItems(8);

  @override
  Widget build(BuildContext context) {
    return SingleChildScrollView(
      child: Container(
        child: _buildPanel(),
      ),
    );
  }

  Widget _buildPanel() {
    return ExpansionPanelList(
      expansionCallback: (int index, bool isExpanded) {
        setState(() {
          _data[index].isExpanded = !isExpanded;
        });
      },
      children: _data.map<ExpansionPanel>((Item item) {
        return ExpansionPanel(
          headerBuilder: (BuildContext context, bool isExpanded) {
            return ListTile(
              title: Text(item.headerValue),
            );
          },
          body: ListTile(
              title: Text(item.expandedValue),
              subtitle:
                  const Text('To delete this panel, tap the trash can icon'),
              trailing: const Icon(Icons.delete),
              onTap: () {
                setState(() {
                  _data.removeWhere((Item currentItem) => item == currentItem);
                });
              }),
          isExpanded: item.isExpanded,
        );
      }).toList(),
    );
  }
}

    You will get some idea

    Thank you

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  2. 0

    Okay you can achieve your goal using ExpandablePanel widget. I have used this package. I have tried something like this. These buildCollapsed(), buildExpanded(), expandedColumn() are custom made function according to your need.

    ExpandablePanel(
  theme: const ExpandableThemeData(
    headerAlignment:
        ExpandablePanelHeaderAlignment.center,
    //tapBodyToExpand: true,
    //tapBodyToCollapse: true,
    hasIcon: false,
  ),
  header: Expandable(
    collapsed: buildCollapsed(), // widget header when the widget is Collapsed
    expanded: buildExpanded(), // header when the widget is Expanded
  ),
  collapsed: Container(), // body when the widget is Collapsed, I didnt need anything here. 
  expanded:  expandedColumn() // body when the widget is Expanded
) '

    For better understanding, go through the package doc and let me know if you have any question.

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