How to detect when WIFI Connection has been establ

Question

I need to detect when I have network connectivity over WIFI. What broadcast is sent to establish that a valid network connection has been made. I need to validate that a valid network connection for HTTP exists. What should I listen for and what additional tests do I need to make to know that a valid connection exists.

Answer 1

You can start a wifi connection if you give the user a choice to override the normal behavior of asking each time.

I choose to use three methods...

public boolean isOnline() 
{
 ConnectivityManager connMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
 NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
 return (networkInfo != null && networkInfo.isConnected());
}  

This is quick check if there is an internet connect either Wifi or CellData. From here you can choose what action you want to take. Is it in Airplane mode needs to be checked also.

On a separate thread. I set a variable IpAddress to = " " And poll until I have a valid an ip address.

  WifiManager wifi;
  wifi = (WifiManager) this.getSystemService(Context.WIFI_SERVICE);
  WifiInfo wifiInfo = wifi.getConnectionInfo();
  int ipAddress = wifiInfo.getIpAddress();
  String ip = null;
  ip = String.format("%d.%d.%d.%d",
  (ipAddress & 0xff),
  (ipAddress >> 8 & 0xff),
  (ipAddress >> 16 & 0xff),
  (ipAddress >> 24 & 0xff));
  Log.e(" >>IP number Begin ",ip);

Another code snippet... If its not on turn it on (with users prior permission)

   if(wifi.isWifiEnabled()!=true)wifi.setWifiEnabled(true);  

Answer 2

To detect WIFI connection state, I have used CONNECTIVITY_ACTION from ConnectivityManager class so:

    IntentFilter filter=new IntentFilter();
    filter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
    registerReceiver(receiver, filter);

and from your BroadCastReceiver:

    if (ConnectivityManager.CONNECTIVITY_ACTION.equals(action)) {
        int networkType = intent.getIntExtra(
                android.net.ConnectivityManager.EXTRA_NETWORK_TYPE, -1);
        if (ConnectivityManager.TYPE_WIFI == networkType) {
            NetworkInfo networkInfo = (NetworkInfo) intent
                    .getParcelableExtra(WifiManager.EXTRA_NETWORK_INFO);
            if (networkInfo != null) {
                if (networkInfo.isConnected()) {

                    // TODO: wifi is connected
                } else {
                    // TODO: wifi is not connected
                }
            }
        }

    }

ps:works fine for me:)

Answer 3

For all those who enjoying CONNECTIVITY_CHANGE broadcast, please note this is no more fired when app is in background in Android O.

https://developer.android.com/about/versions/o/background.html

Answer 4

Answer given by user @JPM and @usman are really very useful. It works fine but in my case it come in onReceive multiple time in my case 4 times so my code execute multiple time.

I do some modification and make as per my requirement and now it comes only 1 time

Here is java class for Broadcast.

public class WifiReceiver extends BroadcastReceiver {

String TAG = getClass().getSimpleName();
private Context mContext;

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

    mContext = context;


    if (intent.getAction().equals(ConnectivityManager.CONNECTIVITY_ACTION)) {

        ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = cm.getActiveNetworkInfo();

        if (networkInfo != null && networkInfo.getType() == ConnectivityManager.TYPE_WIFI &&
                networkInfo.isConnected()) {
            // Wifi is connected
            WifiManager wifiManager = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
            WifiInfo wifiInfo = wifiManager.getConnectionInfo();
            String ssid = wifiInfo.getSSID();

            Log.e(TAG, " -- Wifi connected --- " + " SSID " + ssid );

        }
    }
    else if (intent.getAction().equalsIgnoreCase(WifiManager.WIFI_STATE_CHANGED_ACTION))
    {
        int wifiState = intent.getIntExtra(WifiManager.EXTRA_WIFI_STATE, WifiManager.WIFI_STATE_UNKNOWN);
        if (wifiState == WifiManager.WIFI_STATE_DISABLED)
        {
            Log.e(TAG, " ----- Wifi  Disconnected ----- ");
        }

    }
}
}

In AndroidManifest

<receiver android:name=".util.WifiReceiver" android:enabled="true">
        <intent-filter>
            <action android:name="android.net.wifi.WIFI_STATE_CHANGED" />
            <action android:name="android.net.conn.CONNECTIVITY_CHANGE"/>
        </intent-filter>
    </receiver>


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

Answer 5

Here is an example of my code, that takes into account the users preference of only allowing comms when connected to Wifi.

I am calling this code from inside an IntentService before I attempt to download stuff.

Note that NetworkInfo will be null if there is no network connection of any kind.

private boolean canConnect()
{
    ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);

    boolean canConnect = false;
    boolean wifiOnly = SharedPreferencesUtils.wifiOnly();

    NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
    if(networkInfo != null)
    {
        if(networkInfo.isConnected())
        {
            if((networkInfo.getType() == ConnectivityManager.TYPE_WIFI) ||
               (networkInfo.getType() != ConnectivityManager.TYPE_WIFI && !wifiOnly))
            {
                canConnect = true;
            }
        }
    }

    return canConnect;
}

Answer 6

For me only WifiManager.NETWORK_STATE_CHANGED_ACTION works.

Register a broadcast receiver:

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

and receive:

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

    final String action = intent.getAction();

    if(action.equals(WifiManager.NETWORK_STATE_CHANGED_ACTION)){
        NetworkInfo info = intent.getParcelableExtra(WifiManager.EXTRA_NETWORK_INFO);
        boolean connected = info.isConnected();

        //call your method
    }      
}