Get Network connection warning in Android

Question

I am trying to programmatically detect, when an Android phone is triggering this "warning", that the established internet connection currently seems to be unreachable (In this case: Edge / 2G), like this:

Indeed when this warning appears, the internet cannot be accessed, without it, it works.

What i am currently doing is to detect the correct network:

public String getNetworkClass() {

    if (ActivityCompat.checkSelfPermission(context, Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) {
        return "Unknown";
    } else {
        int networkType = mTelephonyManager.getNetworkType();
        Log.i("NETWORK", String.valueOf(networkType));
        mobileNetworkType = networkType;

        switch (networkType) {
            case TelephonyManager.NETWORK_TYPE_GPRS:
            case TelephonyManager.NETWORK_TYPE_EDGE:
            case TelephonyManager.NETWORK_TYPE_CDMA:
            case TelephonyManager.NETWORK_TYPE_1xRTT:
            case TelephonyManager.NETWORK_TYPE_IDEN:
                return "2G";
            case TelephonyManager.NETWORK_TYPE_UMTS:
            case TelephonyManager.NETWORK_TYPE_EVDO_0:
            case TelephonyManager.NETWORK_TYPE_EVDO_A:
            case TelephonyManager.NETWORK_TYPE_HSDPA:
            case TelephonyManager.NETWORK_TYPE_HSUPA:
            case TelephonyManager.NETWORK_TYPE_HSPA:
            case TelephonyManager.NETWORK_TYPE_EVDO_B:
            case TelephonyManager.NETWORK_TYPE_EHRPD:
            case TelephonyManager.NETWORK_TYPE_HSPAP:
                return "3G";
            case TelephonyManager.NETWORK_TYPE_LTE:
                return "4G";
            case TelephonyManager.NETWORK_TYPE_NR:
                return "5G";
            default:
                return "Unknown";
        }
    }
}

When it is 2G, i am measuring the download / upload rate. I orientated myself here to guess that a download rate below 150 kbps might cause that "warning":

if(Arrays.asList(new String[]{"2G"}).contains(getNetworkClass())) {
    ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkCapabilities nc = cm.getNetworkCapabilities(cm.getActiveNetwork());
    int downSpeed = nc.getLinkDownstreamBandwidthKbps();
    int upSpeed = nc.getLinkUpstreamBandwidthKbps();
    

    if(downSpeed < 150) {
        // I assume the connection is bad here                            
    } else {
        // All fine!
    }

However, my measured values are between 30 and 100 kbps (every five seconds), and sometimes within this range, the warning appears, sometimes not.

How can i successfully capture this? Is there any Android interface to check this? If possible, i would like to avoid ping checks like:

public boolean canAccessInternet() {
    Runtime runtime = Runtime.getRuntime();
    try {
        Process ipProcess = runtime.exec("/system/bin/ping -c 1 8.8.8.8");
        int exitValue = ipProcess.waitFor();
        System.out.println("Network mExitValue " + exitValue);
        return (exitValue == 0);
    } catch (IOException e) {
        System.out.println(" IO Error ");
        e.printStackTrace();
    } catch (InterruptedException e) {
        System.out.println(" Interrupted Error ");
        e.printStackTrace();
    }
    return false;
}

score 1 · Accepted Answer · answered May 26 '22 at 04:27

AFAIK, the UX you referenced with the exclamation point showing on a connectivity icon is driven by the network capability NET_CAPABILITY_VALIDATED (link).

Indicates that connectivity on this network was successfully validated. For example, for a network with NET_CAPABILITY_INTERNET, it means that Internet connectivity was successfully detected.

Therefore in your code, you would update it to this:

...
ConnectivityManager cm = (ConnectivityManager) context.getSystemService(
    Context.CONNECTIVITY_SERVICE);
NetworkCapabilities nc = cm.getNetworkCapabilities(cm.getActiveNetwork());
if(!nc.hasCapability(NET_CAPABILITY_VALIDATED)) {
    // Show the exclamation point
}

Indeed it helped, thank you! Further investigation has shown that if especially happens when freshly enabling mobile internet, but also sometimes in between. Together with my speed measurements its a good result now! — Gary Klasen, May 27 '22 at 17:14

Get Network connection warning in Android

1 Answers1