How to communicate with HostApduService from an Activity

Question

I have asked this question here but it was marked as duplicate - however I didn't find any solution helpful mentioned in comments. Here, I am asking again with more details ... I am doing a sample app (PoC) on HCE and using HostApduService as per Android user guide. I have created two apps 1) ReaderApp - acting as card reader 2) HCEApp - emulating a card In HCEApp, I have created a class 'MyService' extending HostApduService ``` public class MyService extends HostApduService { private int messageCounter; private final String TAG = "MyService"; Intent mIntent; @Override public void onCreate() { super.onCreate(); Log.i(TAG, "onCreate"); mIntent = new Intent(this, MyActivity.class); mIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); startActivity(mIntent); } /** * returned bytes will be sent as response. This method runs in Main thread * so return ASAP. */ @Override public byte[] processCommandApdu(byte[] apdu, Bundle extras) { if (selectAidApdu(apdu)) { Log.i(TAG, "Application selected");…

Accepted Answer

Whether you can use onBind or not I do not know, but I recently worked with a BroadcastReceiver from which I had to start a Service. You cannot `bind` a Service from a BroadcastReceiver according to docs, you can only `start` it. I needed to send some data to the Service from my BroadcastReceiver at some later point, and since the binder techniques was not available to me, I had to find a different way to communicate with the Service, much like your case where you don't have a reference to it.

I did some research but could not find any solution, but then I remembered that you can pass intent data with the startService(intent) call. I start my Service work in onCreate instead, as onCreate is only called once when the Service is created.

In your Activity

```
public void sendDataToService(){
    Intent intent = new Intent(context, MyService.class);
    intent.putExtra("message", SOME_DATA);
    context.startService(intent);
}
```

In your Service

```
@Override
public int onStartCommand(Intent intent, int flags, int startId) {

// Check if intent has extras
    if(intent.getExtras() != null){

// Get message
        int message = intent.getExtras().getInt("message");
    }

return START_NOT_STICKY;
}
```

This may be some sort what of a hack since "startService" does not sound like it should be used to send messages, and am not sure if this is exactly what you need, but it worked for me, so I hope it works for you. Cheers

Edit: BTW. I use it to tell a LocationService that a particular activity no longer want location updates.

How to communicate with HostApduService from an Activity

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