Question

Possible Duplicate:
How to check internet access on Android? InetAddress never timeouts

I need to detect whether the Android device is connected to the Internet.

The NetworkInfo class provides a non-static method isAvailable() that sounds perfect.

Problem is that:

NetworkInfo ni = new NetworkInfo();
if (!ni.isAvailable()) {
    // do something
}

throws this error:

The constructor NetworkInfo is not visible.

Safe bet is there is another class that returns a NetworkInfo object. But I don’t know which.

1. How to get the above snippet of code to work?
2. How could I have found myself the information I needed in the online documentation?
3. Can you suggest a better way for this type of detection?

Answer 1

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.