System managed connection - place outbound call without treating it as a sim call

Question

I'm working on implementing the calling functionality for a voip app and struggling with making an outbound call with a system managed connection service **

The part I'm struggling with is as follows:

    val extras = Bundle()
    extras.putString(EXTRA_PHONE_ACCOUNT_HANDLE, phoneAccountHandle.id) // I assume I need this, otherwise how will it know which connection service to invoke?
    telecomManager.placeCall(Uri.parse("tel:+4412345"), extras)

what I'd like to happen is that the default dialler is invoked and then because I told it my own phone account handle it will then callback to my own implementation of connection service via: onCreateOutgoingConnection where I can then rig up the voip call and maintain the connection state myself.

What actually happens however is that the default dialler is invoked and then it just attempts to ring it as it would with a normal sim call (so I can't broker the connection myself via webrtc)

My setup for the phone account is as follows:

    val extras = Bundle()
    val builder = PhoneAccount.builder(phoneAccountHandle, label)
    builder.setCapabilities(PhoneAccount.CAPABILITY_CONNECTION_MANAGER) // because I want to manage my own call connections but use default UI
    builder.setCapabilities(PhoneAccount.CAPABILITY_CALL_PROVIDER) // because I want to make calls
    // builder.setCapabilities(PhoneAccount.CAPABILITY_SELF_MANAGED) // commented out because otherwise I have to be self managed for inbound
    builder.setExtras(extras)
    val phoneAccount = builder.build()

    telecomManager.registerPhoneAccount(phoneAccount)

For what it's worth I've figured out the inbound side of things and that's working pretty well (I receive a firebase message, I tell telecom there is an inbound call, it then calls back to onCreateIncomingConnection , it then invokes the default in call UI, and I then crack on with completing the webrtc connection between both parties)

I'm fairly new to android development so I'm hoping that I've missed something "obvious" as opposed to what I'm attempting being impossible. Can anyone give me any help on this?

Note: I'm aware of the documentation at https://developer.android.com/guide/topics/connectivity/telecom/selfManaged but that is for a self managed connection, (also, I did initially follow this when attempting a self-managed solution but then gave up (see below). In my case I don't really want to show my own UI (because that would break symmetry with the inbound calls - and then I have the pain of trying to interoperate with other UIs correctly))

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** The reason I've chosen system managed over self managed is that I have to play nicely with other sim calls and I had a world of pain trying to handle the case that my app call follows an ongoing sim call (seemed that nothing I did to my own connection did anything to cause a change in the other connection (like hold the call) so I wound up with two calls going on at the same time).

Update : helps if I add the right kind of extra. it should be parcelable and provide the phoneAccountHandle... managed to get a bit further and may answer my own question if I get this working...

Answer 1

My mistake here (left in original post for posterity) is that instead of adding the phone account handle id as a string extra when placing the call, I should have supplied the actual phone account handle as a parcelable extra. This now brings up the default UI, calls out to my connection service and then does nothing (which is fine because I haven't rigged up the webrtc yet)