interactive ussd session(multi step) does not work on android 8(Oreo)

I am able to get a menu, respond to it by sending a number but past that, I guess am at the mercy of the telco - they send a menu that blocks the entire screen and if you cancel it the entire session dies. Having worked in telecom, I think that this might be different from telco to telco because some of them have gateways that can kill a user initiated session and replace it with a telecom side originated session. technically, the 2 sessions are detached. but here is my code:

    package org.rootio.test.telephony.telephonyautorespond;

import android.annotation.TargetApi;
import android.app.Activity;
import android.content.Context;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.os.ResultReceiver;
import android.telecom.TelecomManager;
import android.telephony.PhoneStateListener;
import android.telephony.SubscriptionManager;
import android.telephony.TelephonyManager;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import android.widget.Switch;
import android.widget.Toast;

import com.google.android.material.snackbar.Snackbar;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import androidx.annotation.RequiresApi;

import static android.content.ContentValues.TAG;

interface UssdResultNotifiable {
    void notifyUssdResult(String request, String returnMessage, int resultCode);
}

public class HomeActivity extends Activity implements UssdResultNotifiable {

    USSDSessionHandler hdl;
    private TelephonyManager telephonyManager;
    private PhoneCallListener listener;
    private TelecomManager telecomManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home);
    }

    public void onUssdSend(View view) {
        //USSDHandler callback = new USSDHandler(view);
        /* if (checkSelfPermission(Manifest.permission.CALL_PHONE) != PackageManager.PERMISSION_GRANTED) {
         *//*if(ActivityCompat.shouldShowRequestPermissionRationale(HomeActivity.this, Manifest.permission.CALL_PHONE))
                    {

                    }
                    else
                    {*//*
                        //ActivityCompat.requestPermissions(HomeActivity.this, new String[]{Manifest.permission.CALL_PHONE}, 0);
                   // }
                    Snackbar.make(view, "permissions were missing", Snackbar.LENGTH_LONG)
                            .setAction("Response", null).show();
                    return;
                }*/
        //HomeActivity.this.telephonyManager.sendUssdRequest("*#123*99#", callback, new Handler());



        hdl = new USSDSessionHandler(HomeActivity.this, HomeActivity.this);

        hdl.doSession(((EditText)this.findViewById(R.id.ussdText)).getText().toString());

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_home, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    public void toggleListener(View v) {
        if (((Switch) v).isChecked()) {
            this.listenForTelephony();
            Toast.makeText(this, "Listening for calls", Toast.LENGTH_LONG).show();
        } else {
            this.stopListeningForTelephony();
        }
    }

    private void listenForTelephony() {
        this.telephonyManager = (TelephonyManager) this.getSystemService(this.TELEPHONY_SERVICE);
        this.telecomManager = (TelecomManager) this.getSystemService(this.TELECOM_SERVICE);
        this.listener = new PhoneCallListener();
        telephonyManager.listen(listener, PhoneStateListener.LISTEN_CALL_STATE);
    }

    private void stopListeningForTelephony() {
        this.telephonyManager = null;
        this.telecomManager = null;
    }

    @Override
    public void notifyUssdResult(final String request, final String returnMessage, final int resultCode) {
        this.runOnUiThread(new Runnable() {
            @Override
            public void run() {
                Toast.makeText(HomeActivity.this, "Request was " + request + "\n response is " + returnMessage + "\n result code is " + resultCode, Toast.LENGTH_LONG).show();

            }
        });

    }


    class PhoneCallListener extends PhoneStateListener {
        @RequiresApi(api = Build.VERSION_CODES.M)
        @Override
        public void onCallStateChanged(int state, String incomingNumber) {

            switch (state) {
                case TelephonyManager.CALL_STATE_RINGING:
                    HomeActivity.this.telecomManager.acceptRingingCall();
                    break;
                case TelephonyManager.CALL_STATE_IDLE:
                    Toast.makeText(HomeActivity.this, "Call is no longer active...", Toast.LENGTH_LONG);
                    break;
            }
        }
    }

    @TargetApi(Build.VERSION_CODES.O)
    class USSDHandler extends TelephonyManager.UssdResponseCallback {

        View parent;

        USSDHandler(View v) {
            this.parent = v;
        }

        @Override
        public void onReceiveUssdResponse(TelephonyManager telephonyManager, String request, CharSequence response) {
            super.onReceiveUssdResponse(telephonyManager, request, response);
            Snackbar.make(this.parent, response, Snackbar.LENGTH_LONG)
                    .setAction("Response", null).show();
        }

        @Override
        public void onReceiveUssdResponseFailed(TelephonyManager telephonyManager, String request, int failureCode) {
            super.onReceiveUssdResponseFailed(telephonyManager, request, failureCode);
            Snackbar.make(this.parent, "error is " + failureCode + " for req " + request, Snackbar.LENGTH_LONG)
                    .setAction("Response", null).show();
        }
    }


}

class USSDSessionHandler {

    TelephonyManager tm;
    private UssdResultNotifiable client;
    private Method handleUssdRequest;
    private Object iTelephony;

    USSDSessionHandler(Context parent, UssdResultNotifiable client) {
        this.client = client;
        this.tm = (TelephonyManager) parent.getSystemService(Context.TELEPHONY_SERVICE);
        try {
            this.getUssdRequestMethod();
        } catch (Exception ex) {
            //log
        }

    }

    private void getUssdRequestMethod() throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        if (tm != null) {
            Class telephonyManagerClass = Class.forName(tm.getClass().getName());
            if (telephonyManagerClass != null) {
                Method getITelephony = telephonyManagerClass.getDeclaredMethod("getITelephony");
                getITelephony.setAccessible(true);
                this.iTelephony = getITelephony.invoke(tm); // Get the internal ITelephony object
                Method[] methodList = iTelephony.getClass().getMethods();
                this.handleUssdRequest = null;
                /*
                 *  Somehow, the method wouldn't come up if I simply used:
                 *  iTelephony.getClass().getMethod('handleUssdRequest')
                 */

                for (Method _m : methodList)
                    if (_m.getName().equals("handleUssdRequest")) {
                        handleUssdRequest = _m;
                        break;
                    }
            }
        }
    }

    public void doSession(String ussdRequest) {
        try {

            if (handleUssdRequest != null) {
                handleUssdRequest.setAccessible(true);
                handleUssdRequest.invoke(iTelephony, SubscriptionManager.getDefaultSubscriptionId(), ussdRequest, new ResultReceiver(new Handler()) {

                    @Override
                    protected void onReceiveResult(int resultCode, Bundle ussdResponse) {
                        /*
                         * Usually you should the getParcelable() response to some Parcel
                         * child class but that's not possible here, since the "UssdResponse"
                         * class isn't in the SDK so we need to
                         * reflect again to get the result of getReturnMessage() and
                         * finally return that!
                         */

                        Object p = ussdResponse.getParcelable("USSD_RESPONSE");

                        if (p != null) {

                            Method[] methodList = p.getClass().getMethods();
                            for(Method m : methodList)
                            {
                                Log.i(TAG, "onReceiveResult: " + m.getName());
                            }
                            try {
                                CharSequence returnMessage = (CharSequence) p.getClass().getMethod("getReturnMessage").invoke(p);
                                CharSequence request = (CharSequence) p.getClass().getMethod("getUssdRequest").invoke(p);
                                USSDSessionHandler.this.client.notifyUssdResult("" + request, "" + returnMessage, resultCode); //they could be null
                            } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
                                e.printStackTrace();
                            }
                        }
                    }

                });
            }
        } catch (IllegalAccessException | InvocationTargetException e1) {
            e1.printStackTrace();
        }
    }
}

please ignore the call answering stuff - I was using this app before to test automatic call answering on Oreo. And below is the Layout file for the display:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".HomeActivity">


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <TextView
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="USSD Input"
            android:textSize="18sp" />

        <EditText
            android:id="@+id/ussdText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:ems="10"
            android:inputType="textPersonName" />
    </LinearLayout>

    <Button
        android:id="@+id/button"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="onUssdSend"
        android:text="send" />
</LinearLayout>

I managed to bypass some of the problems (like the multisession USSD responses not working) by using Reflection. I've made a GitHub gist here.

Obviously the assumption is that, the correct permissions (only CALL_PHONE at this point) are given - In terms of Contexts, I've only ever run this in an Activity but I think it would work fine in most if not all/any.

The next thing is figuring out how to sustain the session, if at all possible.

These APIs don't properly handle menu-based USSDs. Their intended use case would be for things like querying simple things like minutes or data left in the user's plan. For menu-based systems there would need to be some notion of a continued session, which is not something the APIs support.

public class MainActivity extends AppCompatActivity {
private Button dail;
private String number;
private TelephonyManager telephonyManager;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    telephonyManager = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);

    dail = (Button) findViewById(R.id.dail);
    dail.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (ActivityCompat.checkSelfPermission(MainActivity.this, Manifest.permission.CALL_PHONE) != PackageManager.PERMISSION_GRANTED) {
                    runtimepermissions();
                    return;
                }else{
                    telephonyManager.sendUssdRequest("*121#", new TelephonyManager.UssdResponseCallback() {
                        @Override
                        public void onReceiveUssdResponse(TelephonyManager telephonyManager, String request, CharSequence response) {
                            super.onReceiveUssdResponse(telephonyManager, request, response);

                            Log.d("Received response","okay");
                            ((TextView)findViewById(R.id.response)).setText(response);
                        }

                        @Override
                        public void onReceiveUssdResponseFailed(TelephonyManager telephonyManager, String request, int failureCode) {
                            super.onReceiveUssdResponseFailed(telephonyManager, request, failureCode);
                            Log.e("ERROR ","can't receive response"+failureCode);
                        }
                    },new Handler(Looper.getMainLooper()){
                        @Override
                        public void handleMessage(Message msg) {
                            Log.e("ERROR","error");
                        }
                    });
                }

        }
    });

    }
    public boolean runtimepermissions() {
        if (Build.VERSION.SDK_INT >= 23 && ContextCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED
                && ContextCompat.checkSelfPermission(this, Manifest.permission.CALL_PHONE) != PackageManager.PERMISSION_GRANTED) {
            requestPermissions(new String[]{Manifest.permission.READ_PHONE_STATE, Manifest.permission.CALL_PHONE}, 100);
            return true;
        }
        return false;
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == 100) {
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED && grantResults[1] == PackageManager.PERMISSION_GRANTED) {
                Log.d("PERMISSIONS","granted");
               // doJob();
            } else {
                runtimepermissions();
            }
        }

}

}

if your using dual sim make sure change to the network that your going to test(In my i used Airtel(*121#).

Unfortunately the API that Google added in Oreo only works for USSD services where you can dial the entire USSD code at the start and get back the response without entering anything into the session. What they apparently don't realize is that most telcos prevent this for security reasons, especially when there is a PIN entry. The design of the API actually appears to be meant to handle the case of further responses, but as various posters have noted doesn't actually work even as of Android 10.

My company Hover has developed an Android SDK which uses accessibility services to run multi-step USSD sessions and have it appear to happen inside your app. You create configurations for USSD services, trigger the session to run from your app and pass in any runtime variables you need. The user never sees the USSD session and when the response is returned your app is notified and you can parse it as you need. It works on Android 4.3 and above.

The SDK is free to integrate and use until you hit large scale. Please see our docs to get started.

(Disclosure: I am the CTO of Hover)