当我尝试调用State dispose方法内部的方法时，如下所示。

@override
  void dispose() {
    Provider.of<AppProvider>(context, listen: false).close();
    super.dispose();
  }

我来吧。

The following assertion was thrown while finalizing the widget tree:
Looking up a deactivated widget's ancestor is unsafe.

At this point the state of the widget's element tree is no longer stable.

To safely refer to a widget's ancestor in its dispose() method, save a reference to the ancestor by calling dependOnInheritedWidgetOfExactType() in the widget's didChangeDependencies() method.

When the exception was thrown, this was the stack
#0      Element._debugCheckStateIsActiveForAncestorLookup.<anonymous closure> 
package:flutter/…/widgets/framework.dart:3508
#1      Element._debugCheckStateIsActiveForAncestorLookup 
package:flutter/…/widgets/framework.dart:3522
#2      Element.getElementForInheritedWidgetOfExactType 
package:flutter/…/widgets/framework.dart:3588
#3      Provider.of 
package:provider/src/provider.dart:219
#4      _MySecondPageState.dispose 
package:test_space/main.dart:138
...

这是我的示例AppProvider

class AppProvider {
  close() {}
}

我用AppProvider Package 了材料应用程序

return Provider<AppProvider>(
      create: (_) => AppProvider(),
      child: MaterialApp(
        title: 'Flutter Demo',
        theme: ThemeData(
          primarySwatch: Colors.blue,
        ),
        home: HomeScreen(),
        },
      ),
    );

我不知道如何做这个To safely refer to a widget's ancestor in its dispose() method, save a reference to the ancestor by calling dependOnInheritedWidgetOfExactType() in the widget's didChangeDependencies() method.我目前正在使用provider: ^4.0.2。
我以前也是这样做的，**在dispose（）**中使用Provider. of（context），之前没有这个异常。这是因为新的flutter版本吗？另外，我意识到有deactivate（）方法，我应该使用deactivate（）方法而不是dispose（）方法吗？

• [已更新]*

AppProvider _appProvider;
  @override
  void didChangeDependencies() {
    _appProvider = Provider.of<AppProvider>(context, listen: false);
    super.didChangeDependencies();
  }

  @override
  void dispose() {
    _appProvider.close();
    super.dispose();
  }

I could also use deactivate in a certain case

@override
  void deactivate() {
    Provider.of<AppProvider>(context, listen: false)
        .close();
    super.deactivate();
  }