Update NetworkObserver to call connectivityManager.registerDefaultNetworkCallback instead of connectivityManager.registerNetworkCallback

[daniellevass]

Hi,

We'd like to update the NetworkObserver to call connectivityManager.registerDefaultNetworkCallback instead of connectivityManager.registerNetworkCallback to ensure images load across our Android Automotive app regardless of the network assigned.

Android Automotive OEMs use a feature called Per-application network selection (PANS) to separate network traffic amongst various cellular network interfaces. OEMs generally prioritize critical car functionality to an "OEM-paid" network and keep entertainment functionality to a "Customer-paid" network.

Calling registerNetworkCallback is not recommended to track the default network assigned - Google recommend using registerDefaultNetworkCallback to track the default network assigned to the app.

I'm happy to open a pull request for this change, if there are no concerns with this?

Thank you,

Danielle.

[colinrtwhite]

Thanks for the context. I think it's possible changing NetworkObserver to use registerDefaultNetworkCallback could have side effects for existing users so I think we should probably add ImageLoader.Builder.observeDefaultNetwork(true/false) to allow opting into the change. By default we only load over the default network, but it's possible a user could be supplying a custom SocketFactory to use a different network. PR welcome!

I think this is also a good reason to make NetworkObserver public in Coil 3.x so the behaviour can be custom.

[daniellevass]

Thank you so much for your quick feedback! I've opened a PR over here : https://github.com/coil-kt/coil/pull/2379 - any feedback on the PR welcome 🙇‍♀️ I ran the ./test.sh locally, but it looks like CI won't let me know if I did everything okay until someone approves the build 🙈

[colinrtwhite]

This will be available in 2.8.0 - unfortunately I don't have a timeline for when the next release will be.