FormState validation method to return a Map of the validation status of children FormField(s) #135363
Description
Is there an existing issue for this?
- I have searched the existing issues
- I have read the guide to filing a bug
Use case
In a screen containing a relatively long Form in a SingleChildScrollView, we want to bring the user's attention to the field that may cause a validation error after calling FormState.validate(). The solution was as follows:
void _validateForm(BuildContext context) {
if (_fomKey.currentState!.validate()) {
fun();
} else {
WidgetsBinding.instance.addPostFrameCallback((_) {
if (_someWidgetKey.currentContext != null && _someWidgetKey.currentContext!.mounted) {
Scrollable.ensureVisible(
_someWidgetKey.currentContext!,
);
}
});
}
}
Now the problem is that where there are multiple widgets that may cause a validation error. There's currently no way to detect which one we should scroll to.
The only solution is to implement a custom validation logic, which defies the whole purpose of using Form
Proposal
The proposal is to have another version of the validate method, let's call it, validateGranularly (naming suggestions are very welcome) that returns Map<Key, bool>, so the above problem will be addressed as follows:
void _validateForm(BuildContext context) {
if (_fomKey.currentState!.validate()) {
fun();
} else {
Key invalidFieldKey =
_fomKey.currentState!.validateGranularly().firstWehere((e) => !e) // e==false
WidgetsBinding.instance.addPostFrameCallback((_) {
if (invalidFieldKey .currentContext != null && invalidFieldKey .currentContext!.mounted) {
Scrollable.ensureVisible(
invalidFieldKey .currentContext!,
);
}
});
}
}
Metadata
Metadata
Assignees
Labels
Important issues not at the top of the work listEntering text in a text field or keyboard related problemsNothing broken; request for a new capabilityA detailed proposal for a change to Flutterflutter/packages/flutter/material repository.flutter/packages/flutter repository. See also f: labels.Owned by Design Languages teamTriaged by Design Languages team