处理手势时引发了以下断言： Scaffold.of() 使用不包含 Scaffold 的上下文调用

Question

import 'package:flutter/material.dart';

import 'dashboard.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: SafeArea(
        child: Scaffold(
          appBar: AppBar(
            leading: IconButton(
              icon: Icon(Icons.accessible),
              onPressed: () => Scaffold.of(context).openEndDrawer(),
            ),
            title: Text('Sorted.'),
            backgroundColor: Color(0xff0A3D62),
          ),
          drawer: Drawer(
            child: ListView(
              padding: EdgeInsets.zero,
              children: <Widget>[
                new UserAccountsDrawerHeader(
                  accountName: new Text('XYZ'),
                  accountEmail: new Text('XYZ@gmail.com'),
                  currentAccountPicture: new CircleAvatar(),
                )
              ],
            ),
          ),
          body: Center(child: Home()),
        ),
      ),
    );
  }
}

错误：

The following assertion was thrown while handling a gesture:
Scaffold.of() called with a context that does not contain a Scaffold.

No Scaffold ancestor could be found starting from the context that was passed to Scaffold.of(). This usually happens when the context provided is from the same StatefulWidget as that whose build function actually creates the Scaffold widget being sought.

当我尝试从图标打开抽屉时会触发错误。 请帮我解决这个问题。 提前致谢！

Answer 1

@rkdupr0n 说您的context变量没有Scaffold祖先是正确的。 context当前指的是外部build function 传递的内容，它没有Scaffold作为祖先，它只包含它。 因此，您需要获得一个BuildContext ，它具有Scaffold您在树中已经拥有的脚手架，因为它是祖先。 为此，您可以使用Builder小部件来包装需要此上下文的区域：

AppBar(
  leading: Builder(
    builder: (context) {//NEW CONTEXT OBTAINED HERE
      return IconButton(
        icon: Icon(Icons.accessible),
        onPressed: () => Scaffold.of(context).openEndDrawer(),
      );
    }
  ),
  ...
),