Android Wifi How to Detect When Specific Wifi Connection Is Available

Android WIFI How To Detect When Specific WIFI Connection is Available

You can use BroadcastReceiver to find out that wifi network has changed:

BroadcastReceiver broadcastReceiver = new WifiBroadcastReceiver();

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

The BroadcastReceiver may look like this.
And to check for specific MAC address see the checkConnectedToDesiredWifi() method bellow.

public class WifiBroadcastReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (WifiManager.SUPPLICANT_STATE_CHANGED_ACTION .equals(action)) {
            SupplicantState state = intent.getParcelableExtra(WifiManager.EXTRA_NEW_STATE);
            if (SupplicantState.isValidState(state) 
                    && state == SupplicantState.COMPLETED) {

                boolean connected = checkConnectedToDesiredWifi();
            }
        }
    }

    /** Detect you are connected to a specific network. */
    private boolean checkConnectedToDesiredWifi() {
        boolean connected = false;

        String desiredMacAddress = "router mac address";

        WifiManager wifiManager = 
            (WifiManager) context.getSystemService(Context.WIFI_SERVICE);

        WifiInfo wifi = wifiManager.getConnectionInfo();
        if (wifi != null) {
            // get current router Mac address
            String bssid = wifi.getBSSID();
            connected = desiredMacAddress.equals(bssid);
        }

        return connected;
    }
}

Auto Detect a specific wifi connection and start app

try this.

 private void checkWifiConnection() {

    ConnectivityManager connMgr = (ConnectivityManager) c.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo netwifi = connMgr.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
    if (netwifi.getState() == NetworkInfo.State.CONNECTED) {
        WifiInfo info = wifi.getConnectionInfo();
        String ssid = info.getSSID();
        if (ssid.equals("your SSID here")) {
            Toast.makeText(this, "Connected to :" + ssid, Toast.LENGTH_SHORT).show();
        } else {
                 //If not then do nothing.
        }
    }
}

How to check if I am connected to a certain wifi network?

Just define a method that will determine if the device is currently connected to a specific SSID:

public boolean isConnectedTo(String ssid, Context context) {
    boolean retVal = false;
    WifiManager wifi = (WifiManager) context.getApplicationContext().getSystemService(Context.WIFI_SERVICE);
    WifiInfo wifiInfo = wifi.getConnectionInfo();
    if (wifiInfo != null) {
        String currentConnectedSSID = wifiInfo.getSSID();
        if (currentConnectedSSID != null && ssid.equals(currentConnectedSSID)) {
            retVal = true;
        }
    }
    return retVal;
}

Then just use the method like this:

if (isConnectedTo("SOME_SSID", MainActivity.this)) {
    //Call into other class
}

Android - Check internet connection through an specific network (WIFI)

Finally, I came to a solution:

    public interface Consumer {
    void accept(Boolean internet);
}

class InternetCheck extends AsyncTask<Void, Void, Boolean> {

    private Consumer mConsumer;

    public InternetCheck(Consumer consumer) {
        mConsumer = consumer;
        execute();
    }

    @Override
    protected Boolean doInBackground(Void... voids) {
        Socket socket = null;
        try {
            WifiManager wifiManager = (WifiManager) mContext.getApplicationContext().getSystemService(Context.WIFI_SERVICE);
            if (wifiManager != null) {
                socket = new Socket();
                socket.setKeepAlive(false);
                String localIpAddress = getIpAddress(wifiManager);
                socket.bind(new InetSocketAddress(localIpAddress, 0));
                socket.connect(new InetSocketAddress("8.8.8.8", 53), 1500);
                return true;
            }
            return false;
        } catch (IOException e) {
            //unbind();
            return false;
        }finally {
            if(socket != null && !socket.isClosed()) {
                try {
                    socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    @Override
    protected void onPostExecute(Boolean internet) {
        mConsumer.accept(internet);
    }
}

public static String getIpAddress(WifiManager wifiManager) {
    WifiInfo wifiInfo = wifiManager.getConnectionInfo();
    int ipAddress = wifiInfo.getIpAddress();
    return String.format(Locale.getDefault(), "%d.%d.%d.%d", (ipAddress & 0xff), (ipAddress >> 8 & 0xff),
            (ipAddress >> 16 & 0xff), (ipAddress >> 24 & 0xff));
}

I came to a solution after saw this question. With this, I obtained the IP address of my wifi connection and with this, I was able to bind the socket (socket.bind(...)) to the wifi connection and be check if my router had internet access.

I hope this solution helps somebody in the future :)

How do I see if Wi-Fi is connected on Android?

You should be able to use the ConnectivityManager to get the state of the Wi-Fi adapter. From there you can check if it is connected or even available.

ConnectivityManager connManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo mWifi = connManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);

if (mWifi.isConnected()) {
    // Do whatever
}

NOTE: It should be noted (for us n00bies here) that you need to add

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

to your

AndroidManifest.xml for this to work.

NOTE2: public NetworkInfo getNetworkInfo (int networkType) is now deprecated:

This method was deprecated in API level 23. This method does not
support multiple connected networks of the same type. Use
getAllNetworks() and getNetworkInfo(android.net.Network) instead.

NOTE3: public static final int TYPE_WIFI is now deprecated:

This constant was deprecated in API level 28.
Applications should instead use NetworkCapabilities.hasTransport(int) or requestNetwork(NetworkRequest, NetworkCallback) to request an appropriate network. for supported transports.

Detect whether there is an Internet connection available on Android

The getActiveNetworkInfo() method of ConnectivityManager returns a NetworkInfo instance representing the first connected network interface it can find or null if none of the interfaces are connected. Checking if this method returns null should be enough to tell if an internet connection is available or not.

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

You will also need:

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

in your android manifest.

Edit:

Note that having an active network interface doesn't guarantee that a particular networked service is available. Network issues, server downtime, low signal, captive portals, content filters and the like can all prevent your app from reaching a server. For instance you can't tell for sure if your app can reach Twitter until you receive a valid response from the Twitter service.

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