What are the options of collapsable list widgets in Flutter?

Question

I need to have some lists collapse by their topics in my project and am wondering if I'll need to implement this from zero or rather use a component from flutter. Does this component exist?

Thanks in advance :)

Answer 1

The Flutter Gallery has two examples that may be relevant for your accordion-like lists.

Expansion Panel Demo & Two-level List Demo

The Expansion Panel demo is probably what you want. If so, take a look at how the demo leverages ExpansionPanel and uses a headerBuilder and body. You can extends this to make the header and bodies as complex as you need. The Gallery demo adds a DemoItem helper class. You can use this pattern or come up with your own design.

Here is a snippet that shows the demo using ExpansionPanelList by passing a callback and the list of DemoItems:

        child: new ExpansionPanelList(
          expansionCallback: (int index, bool isExpanded) {
            setState(() {
              _demoItems[index].isExpanded = !isExpanded;
            });
          },
          children: _demoItems.map((DemoItem<dynamic> item) {
            return new ExpansionPanel(
              isExpanded: item.isExpanded,
              headerBuilder: item.headerBuilder,
              body: item.build()
            );
          }).toList()
        ),