如何在整个应用程序中而不是为每个页面设置MediaQuery textScaleFactor

Question

final query = MediaQuery.of(context);

return MediaQuery(
  data: query.copyWith(textScaleFactor: 1.4),
  child: MaterialApp(
     title: "Flutter Demo",
     initialRoute: '/loginPage',
  )
);

 ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter (13775): The following assertion was thrown building MyApp(dirty, state: _MyAppState#38690):
I/flutter (13775): MediaQuery.of() called with a context that does not contain a MediaQuery.
I/flutter (13775): No MediaQuery ancestor could be found starting from the context that was passed to MediaQuery.of().
I/flutter (13775): This can happen because you do not have a WidgetsApp or MaterialApp widget (those widgets introduce
I/flutter (13775): a MediaQuery), or it can happen if the context you use comes from a widget above those widgets.

使用MediaQuery类及其数据属性，我想为整个应用程序设置textScaleFactor，但是我不能在MaterialApp之前获得上下文。

final query = MediaQuery.of(context);

return MediaQuery(
  data: query.copyWith(textScaleFactor: 1.4),
  child: Scaffold(
     [...]
  );

Answer 1

最简单的方法是用另一个MaterialApp包装MaterialApp，并设置UseInheritedMediaQuery：

    return MaterialApp(
      home: LayoutBuilder(
        builder: (context, _) { # builder so we can access MaterialApp context
          final query = MediaQuery.of(context);
          return MediaQuery(
              data: query.copyWith(textScaleFactor: 1.4),
              child: MaterialApp( 
                  useInheritedMediaQuery: true, #inherited MediaQuery will be used
                  ....

另一种方法是使用widgetsbinding.instance.window.physicalsizehttps://stackoverflow.com/a/60415290/4679965