How to detect when WIFI Connection has been established in Android?

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 v

Answer 1

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 2

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
    }      
}

Answer 3

I have two methods to detect WIFI connection receiving the application context:

1)my old method

public boolean isConnectedWifi1(Context context) {
    try {
        ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();           
        if (networkInfo != null) {
            NetworkInfo[] netInfo = connectivityManager.getAllNetworkInfo();
            for (NetworkInfo ni : netInfo) {
                if ((ni.getTypeName().equalsIgnoreCase("WIFI"))
                        && ni.isConnected()) {
                    return true;
                }                   
            }
        }
        return false;
    } catch (Exception e) {
        Log.e(TAG, e.getMessage());
    }
    return false;
}

2)my New method (I´m currently using this method):

public boolean isConnectedWifi(Context context) {
         ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
         NetworkInfo networkInfo = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);     
         return networkInfo.isConnected();
}

Answer 4

You can register a BroadcastReceiver to be notified when a WiFi connection is established (or if the connection changed).

Register the BroadcastReceiver:

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

And then in your BroadcastReceiver do something like this:

@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 more info, see the documentation for BroadcastReceiver and WifiManager

Of course you should check whether the device is already connected to WiFi before this.

EDIT: Thanks to ban-geoengineering, here's a method to check whether the device is already connected:

private boolean isConnectedViaWifi() {
     ConnectivityManager connectivityManager = (ConnectivityManager) appObj.getSystemService(Context.CONNECTIVITY_SERVICE);
     NetworkInfo mWifi = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);     
     return mWifi.isConnected();
}

Answer 5

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 6

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:)