The Android.Net.ConnectivityManager class provides information about all the possible network connections for an Android device. To query the network state, the application must request a NetworkInfo object for a type of network. The NetworkInfo class which holds information about a given network type. A instance of NetworkInfo is obtained by calling the GetNetworkInfo member of the ConnectivityManager class. This method takes a ConnectivityType describing which network to query for more information.

This image shows the sample application for this recipe running while connected to different networks:

ℹ️ This recipe requires Android 5.0 (API level 21) or higher.

The first thing the sample application must do is obtain a reference to the ConnectivityManager:

ConnectivityManager connectivityManager = (ConnectivityManager) GetSystemService(ConnectivityService);

To query the device for network state, the app must request the android.permission.ACCESS_NETWORK_STATE in the manifest:

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>

To check if the device is connected to any type of network the ActiveNetworkInfo property of ConnectivityManager returns information about the type of network the device is using. The app uses this NetworkInfo object to see if the device is connected:

NetworkInfo networkInfo = connectivityManager.ActiveNetworkInfo;
bool isOnline = networkInfo.IsConnected;

The property NetworkInfo.Type returns a ConnectivityType value which can be checked to see if the device is connected to a WiFi network:

bool isWifi = networkInfo.Type == ConnectivityType.Wifi;
if(isWifi)
{
    Log.Debug(TAG, "Wifi connected.");
    _wifiImage.SetImageResource(Resource.Drawable.green_square);
} else
{
    Log.Debug(TAG, "Wifi disconnected.");
    _wifiImage.SetImageResource(Resource.Drawable.red_square);
}

The .IsRoaming property on the NetworkInfo class is a boolean value that is used to determine if they device is roaming while connected to a mobile network. The following code snippet from the sample application will display a green square when the device is roaming, and a red square when it is not:

if (networkInfo.IsRoaming)
{
    Log.Debug(TAG, "Roaming.");
    _roamingImage.SetImageResource(Resource.Drawable.green_square);
} else
{
    Log.Debug(TAG, "Not roaming.");
    _roamingImage.SetImageResource(Resource.Drawable.red_square);
}