Android Network State Check, `android.permission.ACCESS_NETWORK_STATE` permission required.

checkNetworkType1.java

// This method was deprecated in API level 28
// https://developer.android.com/reference/android/net/NetworkInfo
import android.net.ConnectivityManager;
import android.net.NetworkInfo;

final ConnectivityManager connMgr = (ConnectivityManager)this.getSystemService(Context.CONNECTIVITY_SERVICE);
final NetworkInfo wifi = connMgr.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
final NetworkInfo mobile = connMgr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
if (wifi.isConnectedOrConnecting()) {
    output.setText("Network Type: WIFI");
} else if (mobile.isConnectedOrConnecting()) {
    output.setText("Network Type: Data");
} else {
    output.setText("Network Type: Unknown");
}

checkNetworkType2.java

// This method was deprecated in API level 28.
// https://developer.android.com/reference/android/net/NetworkInfo
import android.net.ConnectivityManager;
import android.net.NetworkInfo;

final ConnectivityManager connMgr = (ConnectivityManager)this.getSystemService(Context.CONNECTIVITY_SERVICE);
final NetworkInfo activeNetwork = connMgr.getActiveNetworkInfo();
if (activeNetwork == null) {
    output.setText("Network Type: Unknown");
    return;
}
int networkType = activeNetwork.getType();
switch (networkType) {
    case ConnectivityManager.TYPE_WIFI:
        output.setText("Network Type: WIFI");
        break;
    case ConnectivityManager.TYPE_MOBILE:
        output.setText("Network Type: Data");
        break;
    default:
        output.setText("Network Type: Other");
        break;
}

checkNetworkType3.java

import android.net.ConnectivityManager;
import android.net.Network;
import android.net.NetworkCapabilities;

final ConnectivityManager connMgr = (ConnectivityManager)this.getSystemService(Context.CONNECTIVITY_SERVICE);
final Network n = connMgr.getActiveNetwork();
final NetworkCapabilities nc = connMgr.getNetworkCapabilities(n);
if (nc.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR)) {
    output.setText("Network Type: Data");
} else if (nc.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)) {
    output.setText("Network Type: WIFI");
} else {
    // while VPN connected, the result is here
    output.setText("Network Type: Unknown");
}

checkVPNConnected.java

import android.net.ConnectivityManager;
import android.net.Network;
import android.net.NetworkCapabilities;

final ConnectivityManager connMgr = (ConnectivityManager)this.getSystemService(Context.CONNECTIVITY_SERVICE);
final Network n = connMgr.getActiveNetwork();
final NetworkCapabilities nc = connMgr.getNetworkCapabilities(n);
if (nc.hasTransport(NetworkCapabilities.TRANSPORT_VPN)) {
    output.setText("VPN Connected: True");
} else {
    output.setText("VPN Connected: False");
}