buildDropdownButton method

@protected Widget buildDropdownButton(BuildParameters params)

Implementation

@protected
Widget buildDropdownButton(BuildParameters params) {
  final alias = params.props["alias"] ?? params.id;
  final nameKey = params.props["nameKey"] ?? "name";
  final valueKey = params.props["valueKey"] ?? "id";
  final valueList = getMenuValues(params.props["values"], nameKey, valueKey);

  final menuItems = <DropdownMenuItem<String>>[];
  for (var map in valueList) {
    menuItems.add(DropdownMenuItem<String>(
      value: map[valueKey],
      alignment:
          params.buildProp("alignment") ?? AlignmentDirectional.centerStart,
      child: Text(properties.getText(map[nameKey], "menu"),
          overflow: TextOverflow.ellipsis),
    ));
  }

  final enabled = parseBool(params.props["enabled"], defaultValue: true);
  final textStyle =
      enabled ? params.buildProp("style") : params.buildProp("disabledStyle");
  ValueChanged<String?>? onChangeFunc;
  if (enabled) {
    final onChangeAction = events.getValueFunction<String?>(params.context,
        params.actions["onChanged"], params.state, params.parentContext);
    onChangeFunc = (newValue) {
      if (onChangeAction != null) {
        onChangeAction(newValue);
      }
    };
  }

  final widgetMap = <String, Widget>{};
  for (var key in params.widgets.keys) {
    if (params.widgets[key] is List) {
      continue;
    }
    widgetMap[key] = builder.buildWidget(params.context, params.widgets[key],
        params.state, params.parentContext);
  }

  return DropdownButtonFormField<String>(
    key: properties.getKey(params.id),
    style: textStyle,
    focusColor: tryParseColor(params.props["focusColor"]),
    dropdownColor: tryParseColor(params.props["dropdownColor"]),
    iconEnabledColor: tryParseColor(params.props["iconEnabledColor"]),
    iconDisabledColor: tryParseColor(params.props["iconDisabledColor"]),
    elevation: parseInt(params.props["elevation"], defaultValue: 8),
    isExpanded: true,
    itemHeight: tryParseDouble(params.props["itemHeight"]),
    alignment:
        params.buildProp("alignment") ?? AlignmentDirectional.centerStart,
    decoration: params.buildProp("decoration", argument: widgetMap),
    autovalidateMode: AutovalidateMode.disabled,
    hint: builder.tryBuildWidget(params.context, params.widgets["hint"],
        params.state, params.parentContext),
    value: params.props["value"]?.toString(),
    validator: builder.getStringValidator(params.props),
    icon: builder.tryBuildWidget(params.context, params.widgets["icon"],
        params.state, params.parentContext),
    iconSize: parseDouble(params.props["iconSize"], defaultValue: 24.0),
    menuMaxHeight: tryParseDouble(params.props["menuMaxHeight"]),
    items: menuItems,
    onChanged: onChangeFunc,
    onSaved: (v) {
      if (alias != null) {
        params.state[alias] = v;
      }
    },
  );
}