fromDynamic static method

JsonDropdownButtonFormFieldBuilder? fromDynamic(
  1. dynamic map, {
  2. JsonWidgetRegistry? registry,
})

Builds the builder from a Map-like dynamic structure. This expects the JSON format to be of the following structure:

{
  "alignment": <Alignment>,
  "autofocus": <bool>,
  "autovalidateMode": <AutovalidateMode>,
  "borderRadius": <BorderRadius>,
  "decoration": <InputDecorationDecoder>,
  "disabledHint": <JsonWidgetData>,
  "dropdownColor": <Color>,
  "elevation": <int>,
  "enabled": <bool>,
  "focusColor": <Color>,
  "focusNode": <FocusNode>,
  "hint": <JsonWidgetData>,
  "icon": <JsonWidgetData>,
  "items": <String[] | Map<String, dynamic>>,
  "iconDisabledColor": <Color>,
  "iconEnabledColor": <Color>,
  "iconSize": <double>,
  "isDense": <bool>,
  "isExpanded": <bool>,
  "itemHeight": <double>,
  "onChanged": <ValueChanged>,
  "onSaved": <FormFieldSetter>,
  "onTap": <VoidCallback>,
  "selectedItemBuilder": <DropdownButtonBuilder | JsonWidgetData>,
  "validators": <ValueValidator[]>,
  "style": <TextStyle>,
  "value": <dynamic>,
}

As a note, the FocusNode, ValueChanged, FormFieldSetter, and VoidCallback objects cannot be decoded via JSON. Instead, the only way to bind those values to the builder is to use a function or a variable reference via the JsonWidgetRegistry.

The selectedItemBuilder can be a DropdownButtonBuilder or JsonWidgetData. The DropdownButtonBuilder cannot be decoded via JSON and would have to be bound via the JsonWidgetRegistry. If a JsonWidgetData object is used then the item's display will be bound to the dropdown_item_display variable on the registry and the item's value will be bound to dropdown_item_value. This way the widget can associate properties to those two keys for proper rendering.

The items can be either a string array where the string will be used for both the display and the value or a map of strings to values where the key will be used as the display and the value will be the internal dropdown value.

See also:

Implementation

static JsonDropdownButtonFormFieldBuilder? fromDynamic(
  dynamic map, {
  JsonWidgetRegistry? registry,
}) {
  JsonDropdownButtonFormFieldBuilder? result;

  if (map != null) {
    result = JsonDropdownButtonFormFieldBuilder(
      alignment: ThemeDecoder.decodeAlignment(
        map['alignment'],
        validate: false,
      ),
      autofocus: JsonClass.parseBool(map['autofocus']),
      autovalidateMode: map['autovalidate'] == null
          ? ThemeDecoder.decodeAutovalidateMode(map['autovalidateMode'])
          : JsonClass.parseBool(map['autovalidate']) == true
              ? AutovalidateMode.always
              : AutovalidateMode.disabled,
      borderRadius: ThemeDecoder.decodeBorderRadius(map['borderRadius']),
      decoration: map['decoration'],
      disabledHint: JsonWidgetData.fromDynamic(map['disabledHint']),
      dropdownColor: ThemeDecoder.decodeColor(
        map['dropdownColor'],
        validate: false,
      ),
      elevation: JsonClass.parseInt(map['elevation'], 8),
      enableFeedback: map['enableFeedback'] == null
          ? true
          : JsonClass.parseBool(map['enableFeedback']),
      enabled:
          map['enabled'] == null ? true : JsonClass.parseBool(map['enabled']),
      hint: JsonWidgetData.fromDynamic(map['hint']),
      icon: JsonWidgetData.fromDynamic(map['icon']),
      items: map['items'],
      iconDisabledColor: ThemeDecoder.decodeColor(
        map['iconDisabledColor'],
        validate: false,
      ),
      iconEnabledColor: ThemeDecoder.decodeColor(
        map['iconEnabledColor'],
        validate: false,
      ),
      iconSize: JsonClass.parseDouble(map['iconSize'], 24.0),
      isDense:
          map['isDense'] == null ? true : JsonClass.parseBool(map['isDense']),
      isExpanded: JsonClass.parseBool(map['isExpanded']),
      itemHeight: JsonClass.parseDouble(map['itemHeight']),
      menuMaxHeight: JsonClass.parseDouble(map['menuMaxHeight']),
      onChanged: map['onChanged'],
      onSaved: map['onSaved'],
      onTap: map['onTap'],
      selectedItemBuilder: map['selectedItemBuilder'],
      style: ThemeDecoder.decodeTextStyle(
        map['style'],
        validate: false,
      ),
      validator: map['validators'] == null
          ? null
          : Validator.fromDynamic({'validators': map['validators']}),
      value: map['value'],
    );
  }

  return result;
}