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Using Connectivity Plus#

To start using Connectivity Plus, initialize the singleton, which will give you accesss to all methods in the API.

final Connectivity _connectivity = Connectivity();

WiFi or Cellular?#

Using Connectivity API, you can know whether the device is connected to WiFi or to cellular network.

ConnectivityResult connectivityResult = await _connectivity.checkConnectivity();
if (connectivityResult == ConnectivityResult.mobile) {
// I am connected to a mobile network.
} else if (connectivityResult == ConnectivityResult.wifi) {
// I am connected to a wifi network.
}

Using checkConnectivity() method, you may get one of 3 network statuses:

  1. Mobile: connected to a mobile cellular network.
  2. WiFi: connected to WiFi access point.
  3. None: not connected at all.
caution

Note that on Android, this does not guarantee connection to internet. For instance, the app might have WiFi access but it might be a VPN or a hotel WiFi with no access to internet.

Get Notified of Network Changes#

In most use casses, you will probably use this package to know when your user is connected to the internet or not, and for that you are provided with a method that gives you the realtime status of the connection, therefore enable and disable certain parts of your app that dependss on user's connectivity.

1. Declare a StreamSubscription#

StreamSubscription<ConnectivityResult> _connectivitySubscription;

2. Listen to the Stream#

Use onConnectivityChanged method that has a return type Stream<ConnectivityResult>, to register a listener.

note

Note that connectivity changes are no longer communicated to Android apps in the background starting with Android 8.0. You should always check for connectivity status when your app is resumed. The broadcast is only useful when your application is in the foreground.

// Initialize a variable with [none] status to avoid nulls at startup
ConnectivityResult connectivityResult = ConnectivityResult.none;
@override
void initState() {
super.initState();
_connectivitySubscription =
_connectivity.onConnectivityChanged.listen(_updateConnectionStatus);
}
// Make sure to cancel subscription after you are done
@override
dispose() {
super.dispose();
subscription.cancel();
}

The listener will update the connectivity status.

Future<void> _updateConnectionStatus(ConnectivityResult result) async {
setState((){
_connectionResult = result;
});
}
caution

You should not be using the current network status for deciding whether you can reliably make a network connection. Always guard your app code against timeouts and errors that might come from the network layer with try/catch.

[Web Only] Limitations#

In order to retrieve information about the quality/speed of a browser's connection, the web implementation of the connectivity plugin uses the browser's NetworkInformation Web API, which as of this writing (Feburary 2021) is still "experimental", and not available in all browsers:

Data on support for the netinfo feature across the major browsers from caniuse.com

On desktop browsers, this API only returns a very broad set of connectivity statuses (One of 'slow-2g', '2g', '3g', or '4g'), and may not provide a Stream of changes. Firefox still hasn't enabled this feature by default.

Fallback to navigator.onLine

For those browsers where the NetworkInformation Web API is not available, the plugin falls back to the NavigatorOnLine Web API, which is more broadly supported:

Data on support for the online-status feature across the major browsers from caniuse.com

The NavigatorOnLine API is provided by dart:html, and only supports a boolean connectivity status (either online or offline), with no network speed information. In those cases the plugin will return either wifi (when the browser is online) or none (when it's not).

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