小编My *_*Car的帖子

我注意到我的项目中出现了新的 lint 问题。

长话短说：

我需要在我的自定义类中使用 BuildContext

flutter lint 工具与 aysnc 方法一起使用时并不满意。

例子：

   MyCustomClass{

      final buildContext context;
      const MyCustomClass({required this.context});

      myAsyncMethod() async {
        await someFuture();
        # if (!mounted) return;          << has no effect even if i pass state to constructor
        Navigator.of(context).pop(); #   << example
      }
   }

突然这个错误出现在调试控制台中。我不知道我做错了什么。

为什么ValueError: malformed node or string当我将以下格式的数据传递到“parse_webhook”函数时会收到此错误消息？

谢谢！

webhook_data = {"side": "BUY","key": "8234023409fa3242309sdfasdf903024917325"}

def parse_webhook(webhook_data):

    """
    :param webhook_data: POST data from tradingview, as a string.
    :return: Dictionary version of string.
    """

    data = ast.literal_eval(webhook_data)
    return data

我得到错误：

  File "C:\Users\User\anaconda3\lib\ast.py", line 55, in _convert_num
    raise ValueError('malformed node or string: ' + repr(node))

ValueError: malformed node or string: {'side': 'BUY', 'key': '8234023409fa3242309sdfasdf903024917325'}

我正在使用web (Chrome)来运行我的应用程序。但是，我收到错误。这是错误：

\xe2\x95\x90\xe2\x95\x90\xe2\x95\xa1 EXCEPTION CAUGHT BY WIDGETS LIBRARY \xe2\x95\x9e\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\nThe following assertion was thrown building Builder:\nAssertion failed:\nfile:///Users/name/development/flutter/packages/flutter/lib/src/foundation/stack_frame.dart:192:7\nline != \'===== asynchronous gap ===========================\'\n"Got a stack frame from package:stack_trace, where a vm or web frame was expected. This can happen\nif FlutterError.demangleStackTrace was not set in an environment that propagates non-standard stack\ntraces to the framework, such as during tests."\n\nThe relevant error-causing widget was:\n  MaterialApp\n  MaterialApp:file:///Users/name/development/projects/flutter/hello_world/lib/src/hello_world.dart:12:12\n\nWhen the exception was thrown, this was the stack:\ndart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 251:49      throw_\ndart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 29:3        assertFailed\npackages/flutter/src/foundation/stack_frame.dart 192:15                           fromStackTraceLine\ndart-sdk/lib/internal/iterable.dart 391:20                                        moveNext\ndart-sdk/lib/internal/iterable.dart …

我面临一个关于 的问题Unhandled Exception: 'package:flutter/src/widgets/navigator.dart': Failed assertion: line 2845 pos 18: '!navigator._debugLocked': is not true。

这是我的调试控制台：

E/flutter ( 5236): [ERROR:flutter/lib/ui/ui_dart_state.cc(198)] Unhandled Exception: 'package:flutter/src/widgets/navigator.dart': Failed assertion: line 2845 pos 18: '!navigator._debugLocked': is not true.\npackage:flutter/\xe2\x80\xa6/widgets/navigator.dart:2845\nE/flutter ( 5236): #0      _AssertionError._doThrowNew (dart:core-patch/errors_patch.dart:51:61)\nE/flutter ( 5236): #1      _AssertionError._throwNew (dart:core-patch/errors_patch.dart:40:5)\nE/flutter ( 5236): #2      _RouteEntry.handlePush.<anonymous closure>\npackage:flutter/\xe2\x80\xa6/widgets/navigator.dart:2845\nE/flutter ( 5236): #3      TickerFuture.whenCompleteOrCancel.thunk\npackage:flutter/\xe2\x80\xa6/scheduler/ticker.dart:407\nE/flutter ( 5236): #4      _rootRunUnary (dart:async/zone.dart:1434:47)\nE/flutter ( 5236): #5      _CustomZone.runUnary (dart:async/zone.dart:1335:19)\nE/flutter ( 5236): <asynchronous suspension>\nE/flutter ( 5236): #6      TickerFuture.whenCompleteOrCancel.thunk\npackage:flutter/\xe2\x80\xa6/scheduler/ticker.dart:406\nE/flutter ( 5236): <asynchronous suspension>\nE/flutter ( 5236):\n

我在尝试在 DartPad 上运行代码时遇到此问题。

'runZoned' is deprecated and shouldn't be used. This will be removed in v9.0.0. Use Bloc.Bloc.transformer instead...

正确的更换方法是什么？

代码：

import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';

void main() {
  BlocOverrides.runZoned(
    () => runApp(const App()),
    blocObserver: AppBlocObserver(),
  );
}

/// Custom [BlocObserver] that observes all bloc and cubit state changes.
class AppBlocObserver extends BlocObserver {
  @override
  void onChange(BlocBase bloc, Change change) {
    super.onChange(bloc, change);
    if (bloc is Cubit) print(change);
  }

  @override
  void onTransition(Bloc bloc, Transition transition) {
    super.onTransition(bloc, transition);
    print(transition);
  }
}

我是颤振新手。我面临一个关于 的问题[ERROR:flutter/lib/ui/ui_dart_state.cc(209)] Unhandled Exception: PlatformException。

这是我的调试控制台：

Launching lib\\main.dart on sdk gphone x86 in debug mode...\nlib\\main.dart:1\n\xe2\x88\x9a  Built build\\app\\outputs\\flutter-apk\\app-debug.apk.\nW/FlutterActivityAndFragmentDelegate(10702): A splash screen was provided to Flutter, but this is deprecated. See flutter.dev/go/android-splash-migration for migration steps.\nConnecting to VM Service at ws://127.0.0.1:59535/02E90npmd4s=/ws\nE/flutter (10702): [ERROR:flutter/lib/ui/ui_dart_state.cc(209)] Unhandled Exception: PlatformException(network_error, com.google.android.gms.common.api.ApiException: 7: , null, null)\nE/flutter (10702): #0      StandardMethodCodec.decodeEnvelope\npackage:flutter/\xe2\x80\xa6/services/message_codecs.dart:607\nE/flutter (10702): #1      MethodChannel._invokeMethod\npackage:flutter/\xe2\x80\xa6/services/platform_channel.dart:156\nE/flutter (10702): <asynchronous suspension>\nE/flutter (10702): #2      MethodChannel.invokeMapMethod\npackage:flutter/\xe2\x80\xa6/services/platform_channel.dart:356\nE/flutter (10702): <asynchronous suspension>\nE/flutter (10702): #3      GoogleSignIn._callMethod\npackage:google_sign_in/google_sign_in.dart:244\nE/flutter (10702): <asynchronous suspension>\nE/flutter (10702): #4      GoogleSignIn.signIn.isCanceled (package:google_sign_in/google_sign_in.dart)\nE/flutter (10702): <asynchronous suspension>\nE/flutter …

我正在尝试新的SegmentedButton小部件：

SegmentedButton<int>(
  onSelectionChanged: (i) {},
  showSelectedIcon: false,
  style: ButtonStyle(
    backgroundColor: MaterialStatePropertyAll(Theme.of(context).primaryColor),
    iconColor: MaterialStateProperty.all(Colors.white),
  ),
  segments: const <ButtonSegment<int>>[
    ButtonSegment<int>(
      value: 12,
      icon: Icon(FlutterRemix.thumb_up_fill),
      enabled: true,
    ),
    ButtonSegment<int>(
      value: 20,
      icon: Icon(FlutterRemix.thumb_down_fill),
    ),
  ],
  selected: {12},
),

此代码显示了两个分段按钮，如下所示：

当我设置时，如何自定义选定和未选定按钮的颜色：

backgroundColor: MaterialStatePropertyAll(Theme.of(context).primaryColor),

它确实为选定的和选定的设置背景颜色。

谢谢你！

我能够在 PaginatoredDataTable 上显示普通文本字段。但我想将 PaginatoredDataTable 上的 Firestore 字段显示为流构建器方法。我在互联网上搜索过，但找不到与我的要求相关的内容。如何将 firestore 数据获取到 PaginatedDataTable 源中。或者有什么其他方法请告诉我。寻找解决方案，如果也有可磁带行或可选择行，则非常有用。我只想从 firestore 获取数据，而不是从 firebase auth 获取数据。我将 firestore 集合名称命名为“users”。我也有所不同 需要帮助 如何做到这一点？如果在PaginatedDataTable 中不可能，DataTable 也可以。

以下是我的示例 Firestore 集合和文档结构：

firestore collection name: users

documentID1-
    email: 'email1'
    name : 'name1'
    role : 'role1'
    uid  : 'uid1'

documentID2-
    email: 'email2'
    name : 'name2'
    role : 'role2'
    uid  : 'uid2'   

（20多个文件）

下面是我的示例代码，通常能够以普通文本显示：

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';

class AdminDashboard extends StatefulWidget {
  const AdminDashboard({Key? key}) : super(key: key);

  @override
  _AdminDashboardState createState() => _AdminDashboardState();
}

class _AdminDashboardState extends State<AdminDashboard> …

我需要在每个之间添加一个分隔线NavigationRailDestination。里面 NavigationRail有我们添加的目的地NavigationRailDestination。

它只接受 type 的孩子NavigationRailDestination。

我尝试以这种方式执行此操作，但这不是我想要的，有不必要的填充，我无法使用它，并且当我单击它时它会执行操作

这是我的代码：

 NavigationRail(
  backgroundColor: customTheme.card,
  leading: IconButton(
      onPressed: () => Navigator.of(context).pop(),
      icon: Icon(
        FeatherIcons.chevronLeft,
        size: 20,
        color: theme.colorScheme.onBackground,
      )),
  selectedIndex: _selectedIndex,
  onDestinationSelected: (int index) {
    setState(() {
      _selectedIndex = index;
      controller.animateToPage(index,
          duration: const Duration(milliseconds: 250),
          curve: Curves.easeInOut);
    });
  },
  labelType: NavigationRailLabelType.selected,
  /*------------- Build Tabs -------------------*/
  destinations: [
    NavigationRailDestination(
      icon: const Icon(Icons.dashboard),
      selectedIcon: const Icon(Icons.dashboard),
      label: FxText.titleSmall('Dashboard',
          fontWeight: 500, color: theme.colorScheme.primary),
    ),
    NavigationRailDestination(
      icon: Divider(color: Colors.black),
      selectedIcon: Divider(color: Colors.black), …