Dart APIsettings_listSettingsListPageonSelectPrivacy onSelectPrivacy property Null safety VoidCallback onSelectPrivacy final Implementation final VoidCallback onSelectPrivacy; unself_settings_list settings_list SettingsListPage onSelectPrivacy property SettingsListPage class Constructors SettingsListPage Properties hashCode key onSelectAppearance onSelectData onSelectFeedback onSelectLicense onSelectPrivacy onSelectTerms runtimeType trailing Methods build createElement debugDescribeChildren debugFillProperties noSuchMethod toDiagnosticsNode toString toStringDeep toStringShallow toStringShort Operators operator ==