android how to get indicate when the internet connection is lost?

Question

I'm developing an android application and I want to get a notification when the internet (wifi or packet data connection) connection is lost. On my approach I can get the status of the connection as:

private boolean isNetworkAvailable() {
ConnectivityManager connectivityManager 
      = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
return activeNetworkInfo != null && activeNetworkInfo.isConnected();
}

while having this in the Manifest:

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

How could I be notified automatically when the connection is lost?

Answer 1

For WIFI you could register a broadcast receiver as:

IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(WifiManager.SUPPLICANT_CONNECTION_CHANGE_ACTION);
registerReceiver(broadcastReceiver, intentFilter);

You can also register the receiver in the Manifest.

Then in your receiver:

@Override
public void onReceive(Context context, Intent intent) {
    final String action = intent.getAction();
    if (action.equals(WifiManager.SUPPLICANT_CONNECTION_CHANGE_ACTION)) {
        if (intent.getBooleanExtra(WifiManager.EXTRA_SUPPLICANT_CONNECTED, false)){
            //do stuff
        } else {
            // wifi connection was lost
        }
    }
}

For any type of data connection listeners you could use the following receiver registered as:

<receiver android:name=".receiver.ConnectivityReceiver">
    <intent-filter>
        <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
        <action android:name="android.net.wifi.WIFI_STATE_CHANGED" />
    </intent-filter>
</receiver>

and the in your ConnectivityReceiver:

public class ConnectivityReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
    }
}

In the onReceive method you could check if you have internet connectivity or not using this developer article.