RxFormFieldBuilder<B extends RxBlocTypeBase, T> class

RxFormFieldBuilder is a convenience widget, which makes it easier to build and update responsive form fields with reactive Streams.

It requires a state callback, which returns a Stream of values, and can emmit errors which have to be of type RxFieldException. The values and errors are provided to the builder function in order to be displayed.

If the state Stream emits an error that error is provided to the builder function in order to be displayed.

Important! - any errors emitted by the state Stream, must be of type RxFieldException. The reason for this requirement is that RxFieldException provides a value field as well as an error field, and thus the value provided to the builder is kept and not lost upon update.

It requires a showErrorState callback, which returns a Stream of boolean values which determine when it is time to show any potential errors. !The stream provided by showErrorState must never emmit an error.

A builder function is required, this is a function which gives you access to the current field state, and must return a Widget.

The field state provided to the builder function contains several useful fields: bloc, value, error and showError; reference the documentation of RxFormFieldBuilderState for more information on those fields.

You can optionally provide an RxBloc to the bloc field, if you do the provided bloc would be used, otherwise RxFormFieldBuilder automatically searches for and uses the closest instance up the widget tree of RxBloc of type B.

This is an example of how to make a radio button form field.

Widget build(BuildContext context) =>
    RxFormFieldBuilder<ColorSelectionBlocType, ColorEnum>(
      state: (bloc) => bloc.states.color,
      showErrorState: (bloc) => bloc.states.showErrors,
      builder: (fieldState) => Column(
        children: [
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
            children: [
              Row(
                children: [
                  const Text(
                    'White',
                  ),
                  Radio<Gender>(
                    value: ColorEnum.white,
                    groupValue: fieldState.value,
                    onChanged: fieldState.bloc.events.setColor,
                  ),
                ],
              ),
              Row(
                children: [
                  const Text(
                    'Black',
                  ),
                  Radio<Gender>(
                    value: ColorEnum.black,
                    groupValue: fieldState.value,
                    onChanged: fieldState.bloc.events.setColor,
                  ),
                ],
              ),
            ],
          ),
          //show errors, say for instance the user tries to save the
          //changes to the form, but they forgot to select a color.
          if (fieldState.showError)
            Row(
              children: [
                Text(
                  fieldState.error,
                ),
              ],
            ),
        ],
      ),
    );

This is an example of a drop down menu form field.

Widget build(BuildContext context) =>
    RxFormFieldBuilder<ColorSelectionBlocType, ColorEnum>(
      state: (bloc) => bloc.states.color,
      showErrorState: (bloc) => bloc.states.showErrors,
      builder: (fieldState) => Column(
        children: [
          Center(
            child: DropdownButton<ColorEnum>(
              value: fieldState.value,
              onChanged: fieldState.bloc.events.setColor,
              items: ColorEnum.values
                  .map(
                    (color) => DropdownMenuItem<ColorEnum>(
                      value: color,
                      child: Text(
                        color.toString(),
                      ),
                    ),
                  )
                  .toList(),
            ),
          ),
          //show errors, say for instance the user tries to save the
          //changes to the form, but they forgot to select a color.
          if (fieldState.showError)
            Row(
              children: [
                Text(
                  fieldState.error,
                ),
              ],
            ),
        ],
       ),
    );

Inheritance

Implementers

RxTextFormFieldBuilder

Constructors

RxFormFieldBuilder({required RxFormFieldState<B, T> state, required RxFormFieldShowError<B> showErrorState, required RxFormFieldBuilderFunction<B, T> builder, B? bloc, Key? key}): The default constructor
const

Properties

bloc → B?: You can optionally provide an RxBloc to the bloc field, if you do the provided bloc would be used, otherwise RxFormFieldBuilder automatically searches for and uses the closest instance up the widget tree of RxBloc of type B.
final
builder → RxFormFieldBuilderFunction<B, T>: A builder function is required, this is a function which gives you access to the current field state, and must return a Widget.
final
hashCode → int: The hash code for this object.
no setterinherited
key → Key?: Controls how one widget replaces another widget in the tree.
finalinherited
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited
showErrorState → RxFormFieldShowError<B>: A showErrorState callback, which returns a Stream of boolean values which determine when it is time to show any potential errors. !The stream provided by showErrorState must never emmit an error.
final
state → RxFormFieldState<B, T>: A state callback, which returns a Stream of values which are provided to the builder function in order to be displayed.
final

Methods

createElement() → StatefulElement: Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → RxFormFieldBuilderState<RxBlocTypeBase, dynamic, RxFormFieldBuilder<RxBlocTypeBase, dynamic>>: Creates the mutable state for this widget at a given location in the tree.
override
debugDescribeChildren() → List<DiagnosticsNode>: Returns a list of DiagnosticsNode objects describing this node's children.
inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void: Add additional properties associated with the node.
inherited
noSuchMethod(Invocation invocation) → dynamic: Invoked when a nonexistent method or property is accessed.
inherited
toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode: Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.
inherited
toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) → String: A string representation of this object.
inherited
toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String: Returns a string representation of this node and its descendants.
inherited
toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String: Returns a one-line detailed description of the object.
inherited
toStringShort() → String: A short, textual description of this widget.
inherited

Operators

operator ==(Object other) → bool: The equality operator.
inherited

RxFormFieldBuilder<B extends RxBlocTypeBase, T> class

Constructors

Properties

Methods

Operators

rx_form library