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flutter - NoSuchMethodError : The method 'drive' was called on null

转载 作者：行者123 更新时间：2023-12-03 02:41:41 26 4
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我知道有很多问题的标题类似 NoSuchMethodError: The method '#**something**#' was called on null.通常当您尝试访问空对象的方法时会发生此问题。但是，就我而言，当我尝试将以下代码添加到我的 StatefulWidget 时会显示此异常:

 _handleMyBusinessesTap() {
    Navigator.of(context).push(
    MaterialPageRoute(
      builder: (context) => PageBusinessList(
           firebaseUser: widget.firebaseUser,
      ),
    ),
  );
}

一旦我尝试在我的代码中使用 Navigator 对象，我就会收到此异常。
我能想到的我在此页面中与 Navigator 对象不会导致任何问题的其他页面的唯一区别是我以这种方式构建我的页面: 
 Widget build(BuildContext context) {
  return DefaultTabController(
    length: 3,
    child: Scaffold(
      appBar: _buildAppBar(),
      drawer: _buildDrawer(),
      body: _buildBody(),
    ),
  );
}

我在这里使用 DefaultTabController包含 3 页的正文: 
 Widget _buildBody() {
  return TabBarView(
    children: [
      MyCardScreen(),
      ReceivedScreen(),
      SentScreen(),
    ],
  );
}
_handleMyBusinessesTap方法是我在抽屉中的选项之一，我想带我到一个新页面，但是由于某种原因，一旦我添加它，它就会在标题中抛出这个异常。有人遇到过这个问题并且知道应该如何处理吗？

这是 buildDrawer 方法: 
 Widget _buildDrawer() {
return Drawer(
  child: ListView(
    padding: EdgeInsets.zero,
    children: <Widget>[
      UserAccountsDrawerHeader(
        accountName: _buildAccountNameWidget(),
        accountEmail: _buildAccountEmailWidget(),
        currentAccountPicture: _buildAccountCircleAvatar(),
      ),
      ListTile(title: Text("My Default Business Card"), onTap: _handleMyDefaultBusinessCardTap()),
      ListTile(title: Text("My Businesses"), onTap: _handleMyBusinessesTap()),
      ListTile(title: Text("Terms and Conditions"), onTap: _handleTermsAndConditionsTap()),
      ListTile(title: Text("Privacy Policy"), onTap: _handlePrivacyPolicyTap()),
      ListTile(title: Text("Log Out"), onTap: _handleLogOutTap()),
    ],
  ),
);
}

这是堆栈的其余部分: 
I/flutter (  722): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter (  722): The following assertion was thrown building PageMain(dirty, dependencies: [_InheritedTheme,
I/flutter (  722): _LocalizationsScope-[GlobalKey#b039d]], state: _PageMainWidgetState#e33af):
I/flutter (  722): setState() or markNeedsBuild() called during build.
I/flutter (  722): This Overlay widget cannot be marked as needing to build because the framework is already in the
I/flutter (  722): process of building widgets. A widget can be marked as needing to be built during the build phase
I/flutter (  722): only if one of its ancestors is currently building. This exception is allowed because the framework
I/flutter (  722): builds parent widgets before children, which means a dirty descendant will always be built.
I/flutter (  722): Otherwise, the framework might not visit this widget during this build phase.
I/flutter (  722): The widget on which setState() or markNeedsBuild() was called was:
I/flutter (  722):   Overlay-[LabeledGlobalKey<OverlayState>#51a6b](state: OverlayState#7d0ac(entries:
I/flutter (  722):   [OverlayEntry#f42cb(opaque: false; maintainState: false), OverlayEntry#d6b18(opaque: false;
I/flutter (  722):   maintainState: true), OverlayEntry#75d78(opaque: false; maintainState: false),
I/flutter (  722):   OverlayEntry#02406(opaque: false; maintainState: true), OverlayEntry#8f4e5(opaque: false;
I/flutter (  722):   maintainState: false), OverlayEntry#11c40(opaque: false; maintainState: true)]))
I/flutter (  722): The widget which was currently being built when the offending call was made was:
I/flutter (  722):   PageMain(dirty, dependencies: [_InheritedTheme, _LocalizationsScope-[GlobalKey#b039d]], state:
I/flutter (  722):   _PageMainWidgetState#e33af) 
I/flutter (  722): When the exception was thrown, this was the stack:
I/flutter (  722): #0      Element.markNeedsBuild.<anonymous closure> (package:flutter/src/widgets/framework.dart:3503:11)
I/flutter (  722): #1      Element.markNeedsBuild (package:flutter/src/widgets/framework.dart:3529:6)
I/flutter (  722): #2      State.setState (package:flutter/src/widgets/framework.dart:1133:14)
I/flutter (  722): #3      OverlayState.insertAll (package:flutter/src/widgets/overlay.dart:346:5)
I/flutter (  722): #4      OverlayRoute.install (package:flutter/src/widgets/routes.dart:43:24)
I/flutter (  722): #5      TransitionRoute.install (package:flutter/src/widgets/routes.dart:180:11)
I/flutter (  722): #6      ModalRoute.install (package:flutter/src/widgets/routes.dart:895:11)
I/flutter (  722): #7      NavigatorState.push (package:flutter/src/widgets/navigator.dart:1742:11)
I/flutter (  722): #8      _PageMainWidgetState._handleMyBusinessesTap (package:bizooc_client/pages/page_main.dart:86:27)
I/flutter (  722): #9      _PageMainWidgetState._buildDrawer (package:bizooc_client/pages/page_main.dart:60:57)
I/flutter (  722): #10     _PageMainWidgetState.build (package:bizooc_client/pages/page_main.dart:33:17)
I/flutter (  722): #11     StatefulElement.build (package:flutter/src/widgets/framework.dart:3825:27)
I/flutter (  722): #12     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3739:15)
I/flutter (  722): #13     Element.rebuild (package:flutter/src/widgets/framework.dart:3565:5)
I/flutter (  722): #14     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3722:5)
I/flutter (  722): #15     StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:3864:11)
I/flutter (  722): #16     ComponentElement.mount (package:flutter/src/widgets/framework.dart:3717:5)
I/flutter (  722): #17     Element.inflateWidget (package:flutter/src/widgets/framework.dart:2961:14)
I/flutter (  722): #18     Element.updateChild (package:flutter/src/widgets/framework.dart:2764:12)
I/flutter (  722): #19     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:4876:14)
I/flutter (  722): #20     Element.inflateWidget (package:flutter/src/widgets/framework.dart:2961:14)
I/flutter (  722): #21     Element.updateChild (package:flutter/src/widgets/framework.dart:2764:12)
I/flutter (  722): #22     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3750:16)
I/flutter (  722): #23     Element.rebuild (package:flutter/src/widgets/framework.dart:3565:5)
I/flutter (  722): #24     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3722:5)
I/flutter (  722): #25     ComponentElement.mount (package:flutter/src/widgets/framework.dart:3717:5)
I/flutter (  722): #26     Element.inflateWidget (package:flutter/src/widgets/framework.dart:2961:14)
I/flutter (  722): #27     Element.updateChild (package:flutter/src/widgets/framework.dart:2764:12)
I/flutter (  722): #28     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:4876:14)
I/flutter (  722): #29     Element.inflateWidget (package:flutter/src/widgets/framework.dart:2961:14)
I/flutter (  722): #30     Element.updateChild (package:flutter/src/widgets/framework.dart:2764:12)
I/flutter (  722): #31     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:4876:14)
I/flutter (  722): #32     Element.inflateWidget (package:flutter/src/widgets/framework.dart:2961:14)
I/flutter (  722): #33     Element.updateChild (package:flutter/src/widgets/framework.dart:2764:12)
I/flutter (  722): #34     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:4876:14)
I/flutter (  722): #35     Element.inflateWidget (package:flutter/src/widgets/framework.dart:2961:14)
I/flutter (  722): #36     Element.updateChild (package:flutter/src/widgets/framework.dart:2764:12)
I/flutter (  722): #37     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:4876:14)
I/flutter (  722): #38     Element.inflateWidget (package:flutter/src/widgets/framework.dart:2961:14)
I/flutter (  722): #39     Element.updateChild (package:flutter/src/widgets/framework.dart:2764:12)
I/flutter (  722): #40     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3750:16)
I/flutter (  722): #41     Element.rebuild (package:flutter/src/widgets/framework.dart:3565:5)
I/flutter (  722): #42     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3722:5)
I/flutter (  722): #43     StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:3864:11)
I/flutter (  722): #44     ComponentElement.mount (package:flutter/src/widgets/framework.dart:3717:5)
I/flutter (  722): #45     Element.inflateWidget (package:flutter/src/widgets/framework.dart:2961:14)
I/flutter (  722): #46     Element.updateChild (package:flutter/src/widgets/framework.dart:2764:12)
I/flutter (  722): #47     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3750:16)
I/flutter (  722): #48     Element.rebuild (package:flutter/src/widgets/framework.dart:3565:5)
I/flutter (  722): #49     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3722:5)
I/flutter (  722): #50     ComponentElement.mount (package:flutter/src/widgets/framework.dart:3717:5)
I/flutter (  722): #51     Element.inflateWidget (package:flutter/src/widgets/framework.dart:2961:14)
I/flutter (  722): #52     Element.updateChild (package:flutter/src/widgets/framework.dart:2764:12)
I/flutter (  722): #53     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3750:16)
I/flutter (  722): #54     Element.rebuild (package:flutter/src/widgets/framework.dart:3565:5)
I/flutter (  722): #55     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3722:5)
I/flutter (  722): #56     StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:3864:11)
I/flutter (  722): #57     ComponentElement.mount (package:flutter/src/widgets/framework.dart:3717:5)
I/flutter (  722): #58     Element.inflateWidget (package:flutter/src/widgets/framework.dart:2961:14)
I/flutter (  722): #59     Element.updateChild (package:flutter/src/widgets/framework.dart:2764:12)
I/flutter (  722): #60     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:4876:14)
I/flutter (  722): #61     Element.inflateWidget (package:flutter/src/widgets/framework.dart:2961:14)
I/flutter (  722): #62     Element.updateChild (package:flutter/src/widgets/framework.dart:2764:12)
I/flutter (  722): #63     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3750:16)
I/flutter (  722): #64     Element.rebuild (package:flutter/src/widgets/framework.dart:3565:5)
I/flutter (  722): #65     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3722:5)
I/flutter (  722): #66     ComponentElement.mount (package:flutter/src/widgets/framework.dart:3717:5)
I/flutter (  722): #67     Element.inflateWidget (package:flutter/src/widgets/framework.dart:2961:14)
I/flutter (  722): #68     Element.updateChild (package:flutter/src/widgets/framework.dart:2764:12)
I/flutter (  722): #69     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:4876:14)
I/flutter (  722): #70     Element.inflateWidget (package:flutter/src/widgets/framework.dart:2961:14)
I/flutter (  722): #71     Element.updateChild (package:flutter/src/widgets/framework.dart:2764:12)
I/flutter (  722): #72     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3750:16)
I/flutter (  722): #73     Element.rebuild (package:flutter/src/widgets/framework.dart:3565:5)
I/flutter (  722): #74     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3722:5)
I/flutter (  722): #75     StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:3864:11)
I/flutter (  722): #76     ComponentElement.mount (package:flutter/src/widgets/framework.dart:3717:5)
I/flutter (  722): #77     Element.inflateWidget (package:flutter/src/widgets/framework.dart:2961:14)
I/flutter (  722): #78     Element.updateChild (package:flutter/src/widgets/framework.dart:2764:12)
I/flutter (  722): #79     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3750:16)
I/flutter (  722): #80     Element.rebuild (package:flutter/src/widgets/framework.dart:3565:5)
I/flutter (  722): #81     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3722:5)
I/flutter (  722): #82     ComponentElement.mount (package:flutter/src/widgets/framework.dart:3717:5)
I/flutter (  722): #83     Element.inflateWidget (package:flutter/src/widgets/framework.dart:2961:14)
I/flutter (  722): #84     Element.updateChild (package:flutter/src/widgets/framework.dart:2764:12)
I/flutter (  722): #85     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:4876:14)
I/flutter (  722): #86     Element.inflateWidget (package:flutter/src/widgets/framework.dart:2961:14)
I/flutter (  722): #87     Element.updateChild (package:flutter/src/widgets/framework.dart:2764:12)
I/flutter (  722): #88     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3750:16)
I/flutter (  722): #89     Element.rebuild (package:flutter/src/widgets/framework.dart:3565:5)
I/flutter (  722): #90     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3722:5)
I/flutter (  722): #91     ComponentElement.mount (package:flutter/src/widgets/framework.dart:3717:5)
I/flutter (  722): #92     Element.inflateWidget (package:flutter/src/widgets/framework.dart:2961:14)
I/flutter (  722): #93     Element.updateChild (package:flutter/src/widgets/framework.dart:2764:12)
I/flutter (  722): #94     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3750:16)
I/flutter (  722): #95     Element.rebuild (package:flutter/src/widgets/framework.dart:3565:5)
I/flutter (  722): #96     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3722:5)
I/flutter (  722): #97     StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:3864:11)
I/flutter (  722): #98     ComponentElement.mount (package:flutter/src/widgets/framework.dart:3717:5)
I/flutter (  722): #99     Element.inflateWidget (package:flutter/src/widgets/framework.dart:2961:14)
I/flutter (  722): #100    Element.updateChild (package:flutter/src/widgets/framework.dart:2764:12)
I/flutter (  722): #101    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3750:16)
I/flutter (  722): #102    Element.rebuild (package:flutter/src/widgets/framework.dart:3565:5)
I/flutter (  722): #103    ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3722:5)
I/flutter (  722): #104    StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:3864:11)
I/flutter (  722): #105    ComponentElement.mount (package:flutter/src/widgets/framework.dart:3717:5)
I/flutter (  722): #106    Element.inflateWidget (package:flutter/src/widgets/framework.dart:2961:14)
I/flutter (  722): #107    Element.updateChild (package:flutter/src/widgets/framework.dart:2764:12)
I/flutter (  722): #108    RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:4659:32)
I/flutter (  722): #109    MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4992:17)
I/flutter (  722): #110    Element.updateChild (package:flutter/src/widgets/framework.dart:2753:15)
I/flutter (  722): #111    _TheatreElement.update (package:flutter/src/widgets/overlay.dart:607:16)
I/flutter (  722): #112    Element.updateChild (package:flutter/src/widgets/framework.dart:2753:15)
I/flutter (  722): #113    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3750:16)
I/flutter (  722): #114    Element.rebuild (package:flutter/src/widgets/framework.dart:3565:5)
I/flutter (  722): #115    StatefulElement.update (package:flutter/src/widgets/framework.dart:3894:5)
I/flutter (  722): #116    Element.updateChild (package:flutter/src/widgets/framework.dart:2753:15)
I/flutter (  722): #117    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3750:16)
I/flutter (  722): #118    Element.rebuild (package:flutter/src/widgets/framework.dart:3565:5)
I/flutter (  722): #119    ProxyElement.update (package:flutter/src/widgets/framework.dart:4006:5)
I/flutter (  722): #120    Element.updateChild (package:flutter/src/widgets/framework.dart:2753:15)
I/flutter (  722): #121    SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4883:14)
I/flutter (  722): #122    Element.updateChild (package:flutter/src/widgets/framework.dart:2753:15)
I/flutter (  722): #123    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3750:16)
I/flutter (  722): #124    Element.rebuild (package:flutter/src/widgets/framework.dart:3565:5)
I/flutter (  722): #125    StatefulElement.update (package:flutter/src/widgets/framework.dart:3894:5)
I/flutter (  722): #126    Element.updateChild (package:flutter/src/widgets/framework.dart:2753:15)
I/flutter (  722): #127    SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4883:14)
I/flutter (  722): #128    Element.updateChild (package:flutter/src/widgets/framework.dart:2753:15)
I/flutter (  722): #129    SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4883:14)
I/flutter (  722): #130    Element.updateChild (package:flutter/src/widgets/framework.dart:2753:15)
I/flutter (  722): #131    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3750:16)
I/flutter (  722): #132    Element.rebuild (package:flutter/src/widgets/framework.dart:3565:5)
I/flutter (  722): #133    BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2278:33)
I/flutter (  722): #134    _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding&WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:700:20)
I/flutter (  722): #135    _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:286:5)
I/flutter (  722): #136    _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1012:15)
I/flutter (  722): #137    _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:952:9)
I/flutter (  722): #138    _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:864:5)
I/flutter (  722): #142    _invoke (dart:ui/hooks.dart:219:10)
I/flutter (  722): #143    _drawFrame (dart:ui/hooks.dart:178:3)
I/flutter (  722): (elided 3 frames from package dart:async)
I/flutter (  722): ════════════════════════════════════════════════════════════════════════════════════════════════════
I/flutter (  722): Another exception was thrown: NoSuchMethodError: The getter 'status' was called on null.
I/flutter (  722): Another exception was thrown: NoSuchMethodError: The method 'drive' was called on null.

最佳答案

这是使用回调函数时的常见错误。

   ListTile(title: Text("Log Out"), onTap: _handleLogOutTap()),

要解决您的问题，您有一些选择:

1- 
 ListTile(title: Text("Log Out"), onTap: _handleLogOutTap),

2- 
  ListTile(title: Text("Log Out"), onTap: () => _handleLogOutTap()),

3- 
  ListTile(title: Text("Log Out"), onTap: () { _handleLogOutTap() ; }),

您的所有 ListTile 都一样的。

关于flutter - NoSuchMethodError : The method 'drive' was called on null，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/56329987/

26 4 0
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