GroupBuilder class

A widget that automatically rebuilds the interface based on changes to the state of a GroupController.

The GroupBuilder is similar to a ValueListenableBuilder, but is specifically for managing groups of fields in Formy. It watches a GroupController and rebuilds the widget whenever the group state changes.

This widget is useful for building complex interfaces that depend on the state of a group of form fields.

Properties

• controller: The GroupController this widget will watch.
• child: A static widget that will not be rebuilt when the group state changes.
• builder: A function that returns the widget to be rebuilt. It receives:
  • context: The BuildContext from the widget tree.
  • group: The GroupController being observed.
  • child: The static widget defined in the child property.
• buildWhen: An optional function that returns true if the widget should rebuild. It receives:
  • oldState: The previous GroupState.
  • currentState: The current GroupState.

Example

GroupBuilder(
  controller: GroupController(
    key: 'key',
    fields: [
      FieldConfig(key: 'field1', validators: [IsRequired()]),
      FieldConfig(key: 'field2', validators: [IsRequired()]),
    ],
  ),
  builder: (context, group, child) {
    return Column(
      children: [
        TestForm(group: group),
        Column(
          children:
              List.generate(group.state.errorMessages.length, (index) {
            return Text(group.state.errorMessages[index]);
          }),
        ),
        ElevatedButton(
          onPressed: group.touchAndValidateAllFields,
          child: const Text('Press'),
        ),
      ],
    );
  },
);

See also

• GroupController, which manages the state of a group.