onConnectivityChanged property

Stream<NetworkConnectionInfo> get onConnectivityChanged

监听网络连接变化 / Emits a fresh snapshot whenever connectivity changes.

该流被缓存并支持多订阅，避免多个订阅者各自重复执行一次完整采集（亦见原生 版实现）/ Cached and multi-subscription so N subscribers do not run the whole sampling N times (see the native implementation too).

Implementation

Stream<NetworkConnectionInfo> get onConnectivityChanged =>
    _changes ??= Stream<NetworkConnectionInfo>.multi((controller) {
      StreamSubscription<List<String>>? subscription;
      var active = true;

      Future<void> emit() async {
        if (!active) return;
        final snapshot = await checkConnection();
        if (!active) return;
        controller.add(snapshot);
      }

      unawaited(emit());
      subscription = _adapter.onConnectivityChanged.listen((_) {
        unawaited(emit());
      });
      controller.onCancel = () {
        active = false;
        unawaited(subscription?.cancel());
      };
    });