invalid_widget_preview_private_argument
'@Preview(...)' can only accept arguments that consist of literals and public symbols.
Description
#The analyzer produces this diagnostic when the Preview
constructor is invoked with arguments that contain references to private symbols.
Example
#The following code produces this diagnostic because the constant variable _name
is private to the current library:
import 'package:flutter/widgets.dart';
import 'package:flutter/widget_previews.dart';
const String _name = 'My Foo Preview';
@Preview(name: _name)
Widget myPreview() => Text('Foo');
Common fixes
#If appropriate, the private symbol should be made public:
import 'package:flutter/widgets.dart';
import 'package:flutter/widget_previews.dart';
const String name = 'My Foo Preview';
@Preview(name: name)
Widget myPreview() => Text('Foo');
Otherwise, a different public constant symbol should be used:
import 'package:flutter/widgets.dart';
import 'package:flutter/widget_previews.dart';
@Preview(name: 'My Foo Preview')
Widget myPreview() => Text('Foo');
Unless stated otherwise, the documentation on this site reflects Dart 3.7.3. Page last updated on 2025-05-08. View source or report an issue.