主题修改后，Navigator.pushName报错

Question

之前MaterialApp配置路由路由是写在StateLessWidget中的，所以填充的routes也是好用的。现在由于要动态修改主题，所以把StateLessWidget 修改了 StatefulWidget，可是这样Navigator.of(context).pushName()就会崩溃…

import 'package:FlutterPlayground/blur_test_page.dart';
import 'package:FlutterPlayground/inherited/inherited_test_page.dart';
import 'package:FlutterPlayground/layout_test_page.dart';
import 'package:FlutterPlayground/lifecycle_test_page.dart';
import 'package:FlutterPlayground/router_constant.dart';
import 'package:FlutterPlayground/stateful_widget_page.dart';
import 'package:FlutterPlayground/text_line_height_page.dart';
import 'package:flutter/material.dart';
import 'package:page_life_cycle/page_life_cycle.dart';

import 'gesture_test_page.dart';
import 'state_less_widget_page.dart';

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

class MyApp extends StatefulWidget {

  @override
  State<StatefulWidget> createState() {
    return _HomePageState();
  }
}

class _HomePageState extends State<MyApp> {

  Brightness _mCurrentBrightness = Brightness.light;

  Map<String, WidgetBuilder> routes =  <String, WidgetBuilder>{
    RouterConstant.STATELESS_PAGE: (BuildContext context) => StatelessWidgetPage(),
    RouterConstant.STATEFULL_PAGE: (BuildContext context) => StatefulWidgetPage(),
    RouterConstant.TEXT_LINE_HEIGHT_PAGE: (BuildContext context) => TextlineHeightPage(),
    RouterConstant.BLUR_TEST_PAGE: (BuildContext context) => BlurTestPage(),
    RouterConstant.LAYOUT_TEST_PAGE: (BuildContext context) => LayoutTestPage(),
    RouterConstant.GESTURE_TEST_PAGE: (BuildContext context) => GestureTestPage(),
    RouterConstant.LIFECYCLE_TEST_PAGE: (BuildContext context) => LifecycleTestPage(),
    RouterConstant.INHERITED_TEST_PAGE: (BuildContext context) => InheritedTestPage(),
  };

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        brightness: _mCurrentBrightness,
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      navigatorObservers: [PageNavigatorObserver()],
      // onGenerateRoute: (RouteSettings settings) {
      //   return MaterialPageRoute(builder: (BuildContext context) =>
      //       routes[settings.name].call(context));
      // },
      routes: routes,
      home: Scaffold(
        appBar: AppBar(title: Text("FlutterPlayground")),
        body: _buildBodyWidget(),
      )
    );
  }

  Widget _buildBodyWidget() {
    List<Widget> buttons = new List<Widget>();
    buttons.add(_buildBrightnessSwitch());
    buttons.add(_buildRaisedButton("StatelessPage", () => goToTargetPage(RouterConstant.STATELESS_PAGE)));
    buttons.add(_buildRaisedButton("StatefulPage", () => goToTargetPage(RouterConstant.STATEFULL_PAGE)));
    buttons.add(_buildRaisedButton("Text行高测试", () => goToTargetPage(RouterConstant.TEXT_LINE_HEIGHT_PAGE)));
    buttons.add(_buildRaisedButton("高斯模糊测试", () => goToTargetPage(RouterConstant.BLUR_TEST_PAGE)));
    buttons.add(_buildRaisedButton("布局控件测试", () => goToTargetPage(RouterConstant.LAYOUT_TEST_PAGE)));
    buttons.add(_buildRaisedButton("点击事件相关测试", () => goToTargetPage(RouterConstant.GESTURE_TEST_PAGE)));
    buttons.add(_buildRaisedButton("页面生命周期相关测试", () => goToTargetPage(RouterConstant.LIFECYCLE_TEST_PAGE)));
    buttons.add(_buildRaisedButton("Inherited数据共享", () => goToTargetPage(RouterConstant.INHERITED_TEST_PAGE)));

    return Container(
      alignment: Alignment.topCenter,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.center,
        children: buttons,
      ),
    );
  }

  MaterialButton _buildRaisedButton(String text, VoidCallback callback) {
    return RaisedButton(
        onPressed: callback,
        child: Text(text)
    );
  }

  void goToTargetPage(String routerName) {
    Navigator.pushNamed(context, routerName);
    // Navigator.push(context,  MaterialPageRoute(builder: (BuildContext context) {
    //   return StatefulWidgetPage();
    // }));
  }

  Widget _buildBrightnessSwitch() {
    return Row(
      mainAxisAlignment: MainAxisAlignment.center,
      children: [
        Text("夜间模式: "),
        Switch(value: _mCurrentBrightness == Brightness.dark, onChanged: (bool isSelect) =>
          setState(() {
            _mCurrentBrightness = isSelect ? Brightness.dark : Brightness.light;
          })
        )
      ],
    );
  }
}

错误日志：

An Observatory debugger and profiler on sdk gphone x86 64 arm64 is available at: http://127.0.0.1:5425/dMDerlghKqA=/
I/flutter ( 1113): ══╡ EXCEPTION CAUGHT BY GESTURE ╞═══════════════════════════════════════════════════════════════════
I/flutter ( 1113): The following assertion was thrown while handling a gesture:
I/flutter ( 1113): Navigator operation requested with a context that does not include a Navigator.
I/flutter ( 1113): The context used to push or pop routes from the Navigator must be that of a widget that is a
I/flutter ( 1113): descendant of a Navigator widget.
I/flutter ( 1113):
I/flutter ( 1113): When the exception was thrown, this was the stack:
I/flutter ( 1113): #0      Navigator.of.<anonymous closure> (package:flutter/src/widgets/navigator.dart:2184:9)
I/flutter ( 1113): #1      Navigator.of (package:flutter/src/widgets/navigator.dart:2191:6)
I/flutter ( 1113): #2      Navigator.pushNamed (package:flutter/src/widgets/navigator.dart:1587:22)
I/flutter ( 1113): #3      _HomePageState.goToTargetPage (package:FlutterPlayground/main.dart:92:15)
I/flutter ( 1113): #4      _HomePageState._buildBodyWidget.<anonymous closure> (package:FlutterPlayground/main.dart:66:59)
I/flutter ( 1113): #5      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:993:19)
I/flutter ( 1113): #6      _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:1111:38)
I/flutter ( 1113): #7      GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:183:24)
I/flutter ( 1113): #8      TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:598:11)
I/flutter ( 1113): #9      BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:287:5)
I/flutter ( 1113): #10     BaseTapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:222:7)
I/flutter ( 1113): #11     PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:476:9)
I/flutter ( 1113): #12     PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:77:12)
I/flutter ( 1113): #13     PointerRouter._dispatchEventToRoutes.<anonymous closure> (package:flutter/src/gestures/pointer_router.dart:122:9)
I/flutter ( 1113): #14     _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:377:8)
I/flutter ( 1113): #15     PointerRouter._dispatchEventToRoutes (package:flutter/src/gestures/pointer_router.dart:120:18)
I/flutter ( 1113): #16     PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:106:7)
I/flutter ( 1113): #17     GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:358:19)
I/flutter ( 1113): #18     GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:338:22)
I/flutter ( 1113): #19     RendererBinding.dispatchEvent (package:flutter/src/rendering/binding.dart:267:11)
I/flutter ( 1113): #20     GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:295:7)
I/flutter ( 1113): #21     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:240:7)
I/flutter ( 1113): #22     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:213:7)
I/flutter ( 1113): #26     _invoke1 (dart:ui/hooks.dart:265:10)
I/flutter ( 1113): #27     _dispatchPointerDataPacket (dart:ui/hooks.dart:174:5)
I/flutter ( 1113): (elided 3 frames from dart:async)
I/flutter ( 1113):
I/flutter ( 1113): Handler: "onTap"
I/flutter ( 1113): Recognizer:
I/flutter ( 1113):   TapGestureRecognizer#46398

正在查解决方案，这个问题是不是应该在课程中指出下~

Answer 1

CrazyCodeBoy 2021-07-26 18:24:05

具体你是Navigator.pushName的哪一个页面报的上述错误呢，对比下这个页面和其它不报错的页面结构的差异。

• 提问者 布鲁马3518274 #1

  只要把首页替换为StatefulWidget，全部通过pushName跳转页面的逻辑，全部均会报这个错误

• CrazyCodeBoy 回复 提问者 布鲁马3518274 #2

  前面包个StateLessWidget吧