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": "<List<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": "<List<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'],
              validate: false,
            )
          : JsonClass.parseBool(map['autovalidate']) == true
              ? AutovalidateMode.always
              : AutovalidateMode.disabled,
      borderRadius: ThemeDecoder.decodeBorderRadius(
        map['borderRadius'],
        validate: false,
      ),
      decoration: map['decoration'],
      disabledHint: JsonWidgetData.fromDynamic(map['disabledHint']),
      dropdownColor: ThemeDecoder.decodeColor(
        map['dropdownColor'],
        validate: false,
      ),
      elevation: JsonClass.maybeParseInt(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.maybeParseDouble(map['iconSize'], 24.0),
      isDense:
          map['isDense'] == null ? true : JsonClass.parseBool(map['isDense']),
      isExpanded: JsonClass.parseBool(map['isExpanded']),
      itemHeight: JsonClass.maybeParseDouble(map['itemHeight']),
      menuMaxHeight: JsonClass.maybeParseDouble(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;
}