build method
- BuildContext context,
- WidgetRef ref
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:
- the fields of the widget, which themselves must not change over time, and
- any ambient state obtained from the
contextusing BuildContext.dependOnInheritedWidgetOfExactType.
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 cleanse = ref.watch(cleanseProvider);
final normalise = ref.watch(normaliseProvider);
final partition = ref.watch(partitionProvider);
final keepInSync = ref.watch(keepInSyncProvider);
final useValidation = ref.watch(useValidationSettingProvider);
final ignoreMissingTarget = ref.watch(ignoreMissingTargetProvider);
Future<void> _saveToggleStates() async {
final prefs = await SharedPreferences.getInstance();
// Save the latest provider states to preferences.
await prefs.setBool('cleanse', ref.read(cleanseProvider));
await prefs.setBool('normalise', ref.read(normaliseProvider));
await prefs.setBool('partition', ref.read(partitionProvider));
}
void _resetToggleStates() {
// Reset toggle providers to their defaults by invalidating them.
ref.invalidate(cleanseProvider);
ref.invalidate(normaliseProvider);
ref.invalidate(partitionProvider);
ref.invalidate(keepInSyncProvider);
// Save the reset states to preferences.
_saveToggleStates();
}
Future<void> _saveKeepInSync(bool value) async {
final prefs = await SharedPreferences.getInstance();
// Save "Keep in Sync" state to preferences.
await prefs.setBool('keepInSync', value);
}
return Column(
children: [
Row(
children: [
MarkdownTooltip(
message: '''
**Dataset Toggles Setting:** The default setting of
the dataset toggles, on starting up Rattle, is set
here. During a session with Rattle the toggles may be
changed by the user. If the *Sync* option is set, then
the changes made by the user are tracked and restored
on the next time Rattle is run.
''',
child: const Text(
'Dataset',
style: TextStyle(
fontSize: 20,
fontWeight: FontWeight.bold,
),
),
),
configRowGap,
],
),
configRowGap,
// Build toggle rows synced with providers.
Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
// Toggles section.
const Text(
'Toggles',
style: TextStyle(
fontWeight: FontWeight.bold,
),
),
configRowGap,
Expanded(
child: ToggleRow(
label: 'Cleanse',
value: cleanse,
onChanged: (value) {
ref.read(cleanseProvider.notifier).state = value;
_saveToggleStates();
},
tooltipMessage: '''
**Cleanse Toggle:**
Cleansing prepares the dataset by:
- Removing columns with a single constant value.
- Converting character columns with limited unique values to categoric factors.
Enable for automated cleansing, or disable if not required.
''',
),
),
Expanded(
child: ToggleRow(
label: 'Unify',
value: normalise,
onChanged: (value) {
ref.read(normaliseProvider.notifier).state = value;
_saveToggleStates();
},
tooltipMessage: '''
**Unify Toggle:**
Unifies dataset column names by:
- Converting names to lowercase.
- Replacing spaces with underscores.
Enable for consistent formatting, or disable if original names are preferred.
''',
),
),
Expanded(
child: ToggleRow(
label: 'Partition',
value: partition,
onChanged: (value) {
ref.read(partitionProvider.notifier).state = value;
_saveToggleStates();
},
tooltipMessage: '''
**Partition Toggle:**
Splits the dataset into subsets for predictive modeling:
- **Training:** Builds the model.
- **${useValidation ? 'Validation' : 'Tuning'}:** Tunes the model.
- **Testing:** Evaluates model performance.
Enable for larger datasets, or disable for exploratory analysis.
''',
),
),
MarkdownTooltip(
message: '''
**Keep in Sync Toggle:**
- **On:** Saves toggle changes for current sessions.
- **Off:** Changes are only recovered on restart.
''',
child: const Text(
'Keep in Sync',
style: TextStyle(fontSize: 16),
),
),
MarkdownTooltip(
message: '''
**Keep in Sync Toggle:**
- **On:** Saves toggle changes for current sessions.
- **Off:** Changes are only recovered on restart.
''',
child: Switch(
value: keepInSync,
onChanged: (value) {
ref.read(keepInSyncProvider.notifier).state = value;
_saveKeepInSync(value);
},
),
),
configRowGap,
// Reset Dataset Toggles to default button.
MarkdownTooltip(
message: '''
**Reset Toggles:** Tap here to reset the Dataset Toggles
setting to the default for Rattle.
''',
child: ElevatedButton(
onPressed: _resetToggleStates,
child: const Text('Reset'),
),
),
],
),
settingsGroupGap,
RandomSeed(),
settingsGroupGap,
Partition(),
settingsGroupGap,
// Ignore Missing Target row.
Row(
spacing: configRowSpace,
children: [
MarkdownTooltip(
message: '''
*Note: This setting is not yet having any effect.*
**Ignore Missing Target:**
- **On:** Exclude observations with missing target values from analysis.
- **Off:** Include all observations, even those with missing target values.
''',
child: Row(
children: [
const Text(
'Ignore observations with missing target',
style: TextStyle(fontSize: 16),
),
configRowGap,
Switch(
value: ignoreMissingTarget,
onChanged: (value) async {
ref.read(ignoreMissingTargetProvider.notifier).state =
value;
final prefs = await SharedPreferences.getInstance();
await prefs.setBool('ignoreMissingTarget', value);
},
),
],
),
),
],
),
settingsGroupGap,
Divider(),
],
);
}