The named parameter 'child' isn't defined. in Center() constructor - dart

Question

I ran flutter upgrade today, and now I am getting an error that says-
[dart] The named parameter 'child' isn't defined.
The project is newly created and the default code is untouched, but it still has the same Error:

Answer 1

Clean the project cache by running
flutter clean cache
Then invalidate caches / restart Android Studio or VS Code.

Answer 2

Try Restarting your Analysis Dart Server.
At the bottom of Android Studio click on the Dart Analysis tab
Click on the Restart icon.

Answer 3

In my case it happens when I name the widget with the same name of a flutter component, like so:
class OutlineButton extends StatelessWidget {
#override
Widget build(BuildContext context) {
return OutlineButton(
child: Text('+R\$ 5'),
onPressed: () {},
borderSide: BorderSide(color: Colors.grey),
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(30.0),
),
);
}
}
You need to change the name of the created component with a different name, for example:
class CustomOutlineButton extends StatelessWidget {
#override
Widget build(BuildContext context) {
return OutlineButton(
child: Text('+R\$ 5'),
onPressed: () {},
borderSide: BorderSide(color: Colors.grey),
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(30.0),
),
);
}
}

Answer 4

Go to file Settings
Search Flutter (in the search bar)
Provide Flutter SDK path

Answer 5

Actually, I reinstalled the flutter SDK to solve the problem. After a few days, the same error occurred, but then I Started hovering over the red line, after a minute, the error was solved automatically. I guess the SDK connects with internet to check for all the libraries and syntax stuff once we open the IDE.

Answer 6

It happens because of the old cache. Just clean the cache with the following command
flutter clean cache

Answer 7

I just had the same issue. It looks like I changed a flutter lib file by mistake.
To fix this, without reinstalling Flutter SDK:
go to your Flutter SDK installation path
open terminal and type: git status
it will show the modified files in red (ex: modified: packages/flutter/lib/src/widgets/basic.dart
revert modifications file using: git checkout FILE_PATH (ex: git checkout packages/flutter/lib/src/widgets/basic.dart)

Answer 8

The solution is -
Change the name of the class in which you are using the Center widget because, according to the standards of flutter you cannot write the name of the class same as the widget you are using inside that class. If you do so, then you cannot be able to make child or children inside that widget.
Also, the solution of Felipe Augusto is correct.