build method

  1. @override
Widget build(
  1. BuildContext context,
  2. WidgetRef ref
)
override

Describes the part of the user interface represented by this widget.

The framework calls this method when this widget is inserted into the tree in a given BuildContext and when the dependencies of this widget change (e.g., an InheritedWidget referenced by this widget changes). This method can potentially be called in every frame and should not have any side effects beyond building a widget.

The framework replaces the subtree below this widget with the widget returned by this method, either by updating the existing subtree or by removing the subtree and inflating a new subtree, depending on whether the widget returned by this method can update the root of the existing subtree, as determined by calling Widget.canUpdate.

Typically implementations return a newly created constellation of widgets that are configured with information from this widget's constructor and from the given BuildContext.

The given BuildContext contains information about the location in the tree at which this widget is being built. For example, the context provides the set of inherited widgets for this location in the tree. A given widget might be built with multiple different BuildContext arguments over time if the widget is moved around the tree or if the widget is inserted into the tree in multiple places at once.

The implementation of this method must only depend on:

If a widget's build method is to depend on anything else, use a StatefulWidget instead.

See also:

  • StatelessWidget, which contains the discussion on performance considerations.

Implementation

@override
Widget build(BuildContext context, WidgetRef ref) {
  final randomSeed = ref.watch(randomSeedSettingProvider);
  final randomPartition = ref.watch(randomPartitionSettingProvider);

  Future<void> _saveRandomSeed(int value) async {
    final prefs = await SharedPreferences.getInstance();

    // Save "Random Seed" state to preferences.

    await prefs.setInt('randomSeed', value);
  }

  Future<void> _saveRandomPartition(bool value) async {
    final prefs = await SharedPreferences.getInstance();

    // Save "Random Partition" state to preferences.

    await prefs.setBool('randomPartition', value);
  }

  return Column(
    children: [
      Row(
        children: [
          // Title.

          MarkdownTooltip(
            message: '''

            **Random Seed Setting:**
            The random seed is used to control the randomness.
            Setting a specific seed ensures that results are reproducible.

            - **Default Seed:** The default seed is 42.
            - **Reset:** Use the "Reset" button to restore the default seed.

            ''',
            child: const Text(
              'Random Seed',
              style: TextStyle(
                fontWeight: FontWeight.bold,
              ),
            ),
          ),
          configRowGap,
          RandomSeedRow(
            randomSeed: randomSeed,
            updateSeed: (newSeed) {
              ref.read(randomSeedSettingProvider.notifier).state = newSeed;
              _saveRandomSeed(newSeed);
            },
          ),
          configRowGap,

          MarkdownTooltip(
            message: '''



            ''',
            child: const Text(
              'Random Partition each Model Build',
              style: TextStyle(fontSize: 16),
            ),
          ),
          configRowGap,

          MarkdownTooltip(
            message: '''

            **Random Partition each Model Build:**
            When enabled, the partition will be randomised each time a model is built.
            This is useful if you want to ensure that the model is not biased towards a specific partition.

            ''',
            child: Switch(
              value: randomPartition,
              onChanged: (value) {
                ref
                    .read(
                      randomPartitionSettingProvider.notifier,
                    )
                    .state = value;
                _saveRandomPartition(value);
              },
            ),
          ),
          configRowGap,
          MarkdownTooltip(
            message: '''

            **Reset Random Seed:**
            Clicking this button resets the random seed to the default value of 42.
            This is useful if you want to restore the initial random state.

            ''',
            child: ElevatedButton(
              onPressed: () {
                ref.read(randomSeedSettingProvider.notifier).state = 42;
                _saveRandomSeed(42);

                ref
                    .read(
                      randomPartitionSettingProvider.notifier,
                    )
                    .state = false;
                _saveRandomPartition(false);
              },
              child: const Text('Reset'),
            ),
          ),
        ],
      ),
    ],
  );
}