CupertinoThemeData.brightness 现可为空
Summary
CupertinoThemeData.brightness is now nullable.
Context
CupertinoThemeData.brightness
is now used to override MediaQuery.platformBrightness
for Cupertino widgets.
Before this change,
the CupertinoThemeData.brightness getter returned
Brightness.light when it was set to null.
Description of change
Previously CupertinoThemeData.brightness
was implemented as a getter:
Brightness get brightness => _brightness ?? Brightness.light;
final Brightness _brightness;
It is now a stored property:
final Brightness brightness;
Migration guide
Generally CupertinoThemeData.brightness
is rarely useful outside of the Flutter framework.
To retrieve the brightness for Cupertino widgets,
now use CupertinoTheme.brightnessOf instead.
With this change, it is now possible to override
CupertinoThemeData.brightness in a CupertinoThemeData
subclass to change the brightness override. For example:
class AwaysDarkCupertinoThemeData extends CupertinoThemeData {
Brightness brightness => Brightness.dark;
}
When a CupertinoTheme uses the above CupertinoThemeData,
dark mode is enabled for all its Cupertino descendants
that are affected by this CupertinoTheme.
Timeline
This change was made in January of 2020 after the v1.13.7 release.
References
Design doc:
API documentation:
Relevant issues:
Relevant PRs: