How to check if network is available

Question

I am writing an app which sends some data to the server by POST method and receives a response. To do this, I firstly need to check if network is available. I am using this method:

private boolean isNetworkAvailable() {
    ConnectivityManager connManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo activeNetworkInfo = connManager.getActiveNetworkInfo();

    return activeNetworkInfo != null && activeNetworkInfo.isConnected();
}

However, this function is not very accurate. For example, sometimes my device network indicator in status bar shows that it is currently connected to an EDGE network or a 3G network, but when I try to access the network, it starts changing immediately to another network type and changing back and there is no actual valid connection, but this function still returns true . How to make sure that the network connection is valid and data can be sent through it?

Answer 1

I don't think there is straight away API to check if a connection is valid. you can only detect if you are connected to a router or not. You can try to connect to a known stable domain to check if it connects. But you add extra delay in connection to do this check

Answer 2

You have to try connect to server and get response code to check connection.

try this.

public boolean isOnline(Context context) {
try {
    ConnectivityManager cm = (ConnectivityManager) context .getSystemService(Context.CONNECTIVITY_SERVICE); 
    if (cm.getActiveNetworkInfo().isConnectedOrConnecting()) {
        URL url = new URL("http://www.ripansekhon.blogspot.com");
        HttpURLConnection urlc = (HttpURLConnection) url .openConnection();
        urlc.setRequestProperty("User-Agent", "test");
        urlc.setRequestProperty("Connection", "close"); 
        urlc.setConnectTimeout(1000); // mTimeout is in seconds
        urlc.connect();
        if (urlc.getResponseCode() == 200) {
            return true;
        } else {
            return false;
        }
    }
} catch (IOException e) {
    e.printStackTrace();
}
return false;

}