Bind to AIDL remote service on Android

Question

I have an Android app that specifies two AIDL files and a service. This service should be used from another app to invoke the methods defined on the AIDL. I have followed the Android Documentation on AIDL to implement the AIDL files and the service (see the code below).

Then I created a very simple client app (also shown below) to bind to the service and invoke the method defined on my AIDL file. However, the bindService always returns false and mentions that the intent cannot be found. These are some things I tried to correctly reference the intent on the client side:

Intent intent = new Intent("a.b.c.service");
intent.setPackage("a.b.c");

---

Intent intent = new Intent("service");
intent.setPackage("a.b.c");

---

Intent intent = new Intent();
intent.setClassName("a.b.c", "a.b.c.services.MyService");

---

Intent intent = new Intent();
intent.setClassName("a.b.c.services", "a.b.c.services.MyService");

---

Intent intent = new Intent();
intent.setClassName("a.b.c", ".services.MyService");

---

Intent intent = new Intent();
intent.setAction("service");
intent.setPackage("a.b.c");
intent.setClassName("a.b.c", ".services.MyService");

---

Intent intent = new Intent();
intent.setAction("service");
intent.setClassName("a.b.c", ".services.MyService");

If I try from the same application where the service resides, I can use the following and it will work:

Intent intent = new Intent(this, MyService.class);

But since this is a remote service, I do not have access to MyService class from the client app, so I can't find any way of making it work.

I have wondered through a lot of StackOverflow posts without any luck. Examples:

Android: Binding to a remote service How can I use AIDL remote service to deal with defferent clients' concurrent requests? Android Bind Service returns false every time

How should I specify my intent in this case?

Thanks in advance.

Relevant code:

IServiceInterface.aidl

package a.b.c;

import a.b.c.IServiceInterfaceGetStuffCallback;

interface IServiceInterface
{
    void getStuff(String arg1, IServiceInterfaceGetStuffCallback callback);
}

IServiceInterfaceGetStuffCallback

package a.b.c;

interface IServiceInterfaceGetStuffCallback
{
    void onGetStuffResponse(String arg1, boolean arg2, int arg3, int arg4);
}

a.b.c./services/MyService.java

public class MyService extends Service
{
    private final MyService self = this;
    private MyServiceHandler handler = null;
    private final HandlerThread handlerThread = new HandlerThread("AidlServiceThread");

    //Callbacks
    private final ArrayList getStuffCallbacks = new ArrayList<>();

    private final int MY_SERVICE_GET_STUFF_MSG                                   = 1;

    public MyService()
    {
    }

    @Override
    public IBinder onBind(Intent intent)
    {
        // Handler Thread handling all callback methods
        handlerThread.start();
        handler = new MyServiceHandler(handlerThread.getLooper());

        return mBinder;
    }

    IServiceInterface.Stub mBinder = new IServiceInterface.Stub()
    {
        @Override
        public void getStuff(String arg1, IServiceInterfaceGetStuffCallback callback) throws RemoteException
        {
            //Register the callback internally
            getStuffCallbacks.add(callback);
            final int cbIndex = getStuffCallbacks.size() - 1;

            getStuff((arg1, arg2, arg3, arg4) ->
            {
                MyServiceResponse response = new MyServiceResponse();
                response.arg1 = arg1;
                response.arg2 = arg2;
                response.arg3 = arg3;
                response.arg4 = arg4;

                Message message = handler.obtainMessage();
                message.arg1 = cbIndex;
                message.obj = response;
                message.what = MY_SERVICE_GET_STUFF_MSG;

                handler.sendMessage(message);
            });
        }
    };

    private class MyServiceHandler extends Handler
    {
        int callbackIndex = 0;

        MyServiceHandler (Looper looper)
        {
            super(looper);
        }

        @Override
        public void handleMessage(Message msg)
        {
            callbackIndex = msg.arg1;
            MyServiceHandler response = (MyServiceHandler)msg.obj;

            switch (msg.what)
            {
                case MY_SERVICE_GET_STUFF_MSG:
                {
                    try
                    {                        
getStuffCallbacks.get(callbackIndex).onGetStuffResponse(response.arg1, response.arg2, response.arg3, response.arg4);
                    }
                    catch (RemoteException e)
                    {
                        e.printStackTrace();
                    }

                    break;
                }
                default:
                    break;
            }
        }
    }

    private static class MyServiceResponse
    {
        public String arg1;
        public boolean arg2;
        public int arg3;
        public int arg4;
    }
}

Android Manifest

Client app - MainActivity.java

public class MainActivity extends AppCompatActivity implements View.OnClickListener
{
    private final String TAG = "aidltest";

    MainActivity self = this;
    IServiceInterface service = null;

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

        findViewById(R.id.btn_get_stuff).setOnClickListener(this);
    }

    @Override
    public void onClick(View view)
    {
        if (view.getId() == R.id.btn_get_stuff)
            getStuff();
    }

    void getStuff()
    {
        Log.e(TAG, "getStuff invoked");

        Intent intent = new Intent("a.b.c.myservice");
        intent.setPackage("a.b.c");

        boolean res = getApplicationContext().bindService(intent, serviceConnection, Context.BIND_AUTO_CREATE);

        Log.e(TAG, "Service binding result: " + res);
    }

    private ServiceConnection serviceConnection = new ServiceConnection()
    {
        public void onServiceConnected(ComponentName className, IBinder service)
        {
            // This is called when the connection with the service has been
            // established, giving us the service object we can use to
            // interact with the service.  We are communicating with our
            // service through an IDL interface, so get a client-side
            // representation of that from the raw service object.
            self.service = IServiceInterface.Stub.asInterface(service);

            Log.e(TAG, "ServiceInterface attached");
        }

        public void onServiceDisconnected(ComponentName className)
        {
            service = null;
            Log.e(TAG, "Service disconnected");
        }
    };
}

Bind to AIDL remote service on Android

Answers (1)

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