feat(connectivity_plus): add checkConnectivity.hasConnectivity() utility getter

[EchoEllet]

Description

A very minor feature that is commonly used (e.g., serverpod_flutter):

final result = await checkConnectivity();
print(result.hasConnectivity);

Related Issues

• Fix [Request]: Add hasConnectivity getter extension to List<ConnectivityResult> #3841

Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I titled the PR using Conventional Commits.
• I did not modify the CHANGELOG.md nor the plugin version in pubspec.yaml files.
• All existing and new tests are passing.
• The analyzer (flutter analyze) does not report any problems on my PR.

Breaking Change

Does your PR require plugin users to manually update their apps to accommodate your change?

• Yes, this is a breaking change (please indicate that with a ! in the title as explained in Conventional Commits).
• No, this is not a breaking change.

[EchoEllet]

This PR does not modify sensors_plus, so this CI failure is most likely irrelevant.

[vbuberen]

I like the idea, but there is some work to do before we can merge this.

My main suggestion is to export extension via show as I suggested in one of my review comments.

Additionally, let's add mention and code example with the new extension to the README file and the example app, so it is easy to find for package users.

[vbuberen]

It won't work the way it is described as currently calls like checkConnectivity() are not done without Connectivity() class. And hasConnectivity is only available if there is an import of 'package:connectivity_plus_platform_interface/connectivity_plus_platform_interface.dart' in the file.
So this doc comment is misleading and needs an improvement. I would suggest to move this example comment about hasConnectivity to be above the extension itself.

[EchoEllet]

I would suggest to move this example comment about hasConnectivity to be above the extension itself.

ConnectivityResultListX is inside connectivity_plus_platform_interface, so it should probably not assume the API shape of code that depends on connectivity_plus.

I would avoid the reference to Connectivity() entirely inside the platform interface package.

So this doc comment is misleading and needs an improvement.

With the proposed change, consumers cannot find this extension by only reading connectivity_plus.

I think we can add a doc comment to hasConnectivity instead:

extension ConnectivityResultListX on List<ConnectivityResult> {
  /// Returns whether any active network connection exists.
  bool get hasConnectivity =>
      !(length == 1 && first == ConnectivityResult.none);
}

And then document it in README.md of connectivity_plus instead?

[vbuberen]

Let's add the new extension here to avoid the need for additional import of platform interface by package users.

[EchoEllet]

This will cause a temporary Dart analysis warning since connectivity_plus depends on connectivity_plus_platform_interface from pub.dev, and ConnectivityResultListX does not exist in the latest published version.

Should I add a temporary dependency override, or leave that to the project maintainers?

We also probably want to validate whether ConnectivityResultListX is a good name, because changing it later is a breaking change.