Android Q, programmatically connect to different WiFi AP for internet

Try calling bindProcessToNetwork() in onAvailable() callback to regain network connectivity, it works fine for me.

Connect to network:

    WifiNetworkSpecifier.Builder builder = new WifiNetworkSpecifier.Builder();
    builder.setSsid("wifi-ap-ssid");
    builder.setWpa2Passphrase("wifi-ap-password");

    WifiNetworkSpecifier wifiNetworkSpecifier = builder.build();

    NetworkRequest.Builder networkRequestBuilder1 = new NetworkRequest.Builder();
    networkRequestBuilder1.addTransportType(NetworkCapabilities.TRANSPORT_WIFI);
    networkRequestBuilder1.setNetworkSpecifier(wifiNetworkSpecifier);

    NetworkRequest nr = networkRequestBuilder1.build();
    ConnectivityManager cm = (ConnectivityManager)
            context.getSystemService(Context.CONNECTIVITY_SERVICE);
    ConnectivityManager.NetworkCallback networkCallback = new 
        ConnectivityManager.NetworkCallback() {
        @Override
        public void onAvailable(Network network) {
            super.onAvailable(network);
            Log.d(TAG, "onAvailable:" + network);
            cm.bindProcessToNetwork(network);
        }
    });
    cm.requestNetwork(nr, networkCallback);

Disconnect from the bound network:

cm.unregisterNetworkCallback(networkCallback);