No way to get device callbacks

[Daniel63656]

I am trying to detect when an input device is added on android to update UI. However deviceCallback is private in AndroidMidiAccess. How is one supposed to receive these events? I tried using stateChanges but it always issues 3 changes when I plug/unplug a cable

[atsushieno]

As you tried, it is implemented to invoke MidiAccess.stateChanged() event handler function (not very cool API, only one handler can be set).

It simply dispatches what Android MIDI API emits. If your Android platform emits 3 changes then you will receive 3 events. But I don't think that's the case. It is more likely that you write app in Jetpack Compose and your app triggers multiple state changes for one event. If you still have doubts in ktmidi MidiAccess implementation, maybe please give me some repro code / project so that I can investigate?

[Daniel63656]

These events are fired for each port. If I connect my piano for example, 3 ports are opened, 1 input and 2 output ports, thus 3 state changes.
However one (including me) would like to know when a device has been successfully opened for example. Androids midi API provides a callback for that when calling openOutput().
I would suggest making a unified Midi access listener that receives not just on send but also these device connected/disconnected calls or alternatively a separate listener just for these callbacks

[atsushieno]

Ah okay I understand what you meant. However it is not what ktmidi MidiAccess is like. It is basically following how Web MIDI API organize ports without the concept of "devices". It is by design. If you need platform specific features like this, you should directly use Android MIDI API.