我正在开发一个颤振应用程序(我仍然是个新手),我被以下错误困住了:
Error: Could not find the correct Provider<List<Category>> above this Exercises Widget
This likely happens because you used a `BuildContext` that does not include the provider
of your choice. There are a few common scenarios:
- The provider you are try
我是一个颤振初学者,我正在制作一个应用程序,但我有这样的问题:
总的来说,我编写了以下代码:
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MultiProvider(
providers: [
ChangeNotifierProvider.va
我推了四个屏幕ScreenOne >> ScreenTwo >> ScreenThree >> ScreenFour
我现在在ScreenFour我想回到ScreenTwo
在Swift中,它的工作方式如下:
if let viewControllers: [UIViewController] = self.navigationController!.viewControllers {
for vc in viewControllers
{
if (vc is SecondViewController)
{
我有一个供应商和导航的问题。
我有一个包含对象列表的HomeScreen。当你点击一个对象时,我会导航到一个带有标签导航的DetailScreen。此DetailScreen由提供ViewModel的ChangenotifierProvider包装
现在,当我使用Navigator.of(context).push(EditScreen)导航到另一个屏幕时,我无法在EditScreen中访问ViewModel,会抛出以下错误
════════ Exception caught by gesture ═══════════════════════════════════════════
The
Google登录提供程序类没有导航到下一个屏幕。登录用户工作,但用户必须登录,然后离开应用程序,然后重新打开。重新打开后,该应用程序在用户登录时运行良好。 错误日志显示:[ERROR:flutter/lib/ui/ui_dart_state.cc(209)] Unhandled Exception: Null check operator used on a null value E/flutter ( 9884): #0 StatefulElement.state (package:flutter/src/widgets/framework.dart:4789:44) E/flu