Android - Detect if Wifi Requires Browser Login

Question

My university has an open wifi access point, however it requires you to enter your e-mail before it allows you to use the web. My problem is that the Wifi is stupid in that

Answer 1

I used the following code using google's 204 endpoint.

 private boolean networkAvailable() {

        ConnectivityManager mManager = (ConnectivityManager) getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE);
        if(mManager != null) {
            NetworkInfo activeNetwork = mManager.getActiveNetworkInfo();
            if(activeNetwork== null || !activeNetwork.isConnectedOrConnecting()){
                return false;
            }
        }

        OkHttpClient client = new OkHttpClient();

        Request request = new Request.Builder()
                .url("http://clients1.google.com/generate_204")
                .build();
        try {
            Response response = client.newCall(request).execute();
            if(response.code() != 204)
                return  false; // meaning it either responded with a captive html page or did a redirection to captive portal.
            return true;
        } catch (IOException e) {
            return true;
        }
    }

Many applications including Google Chrome use http://clients1.google.com/generate_204 to verify that the the connection is not locked under captive portal.