Register and unregister connectivity receiver when needed.

android-connectivity-change

private ConnectivityChangeReceiver mConnectivityChangeReceiver;

@Override
protected void onResume() {
    super.onResume();
    mConnectivityChangeReceiver = new ConnectivityChangeReceiver();
    registerReceiver(mConnectivityChangeReceiver, new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION));
}

@Override
protected void onPause() {
    super.onPause();
    unregisterReceiver(mConnectivityChangeReceiver);
}

private class ConnectivityChangeReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        final Bundle extras = intent.getExtras();
        if (extras != null) {
            if (extras.getBoolean(ConnectivityManager.EXTRA_NO_CONNECTIVITY)) {
                
            } else {
               
            }
        }
    }
}