Null safety

[deakjahn]

Minimal changes to support null safety. Also removes dependency on wifi package that lags behind, replacing it with a simple function call. Some deprecated functions also fixed.

[renanzdm]

several packages from this developer seem abandoned to me, it may be necessary to forked this package

[phan-dev]

Minimal changes to support null safety. Also removes dependency on wifi package that lags behind, replacing it with a simple function call. Some deprecated functions also fixed.

@deakjahn
Hi, does it work on iOS without wifi package?

[deakjahn]

I only use it on Android so I can't really tell.

[machointossh]

@phan-dev FYI: I tried this branch and I'm confirmed the flutter_example worked fine on the iOS emulator. (iPhone 12 Pro Max; iOS 14.5)

[joeyw7]

For _getLocalIpAddress, maybe use this package instead. https://pub.dev/packages/network_info_plus

import 'package:network_info_plus/network_info_plus.dart';
final info = NetworkInfo();
var wifiIP = await info.getWifiIP(); 

[deakjahn]

@joeyw7 I tried to add it to my fork (https://github.com/deakjahn/ping_discover_network) but the package would need some refactoring to work well with the new Android embedding. I can't test on iOS, either. It wasn't my original intention to create a new independent fork, just to create the base PR but I don't know if this gets abandoned now here or not.