Flutter - Get data with an Event Channel from Kotlin to Dart - kotlin

Question

I have the following problem that I am already working on for over 20 hours: I want to use an Event Channel to get a data stream from the Spotify SDK. On the native side, I can automatically display the status of a current song by subscribing to my PlayerState. My goal is to be able to access this data stream with my Flutter app. On the native side I can output the data flow without problems. But I also want to be able to access this data in my Flutter App. The problem is that I do not get the data from Kotlin to Dart. I can not execute the command mEventSink?.success(position) because the mEventSink is zero.
It would be really great if someone could help me with this problem.
//...
class Spotifysdk04Plugin(private var registrar: Registrar): MethodCallHandler, EventChannel.StreamHandler {
//...
private var mEventSink: EventChannel.EventSink? = null
companion object {
#JvmStatic
fun registerWith(registrar: Registrar) {
val channel = MethodChannel(registrar.messenger(), "spotifysdk")
channel.setMethodCallHandler(Spotifysdk04Plugin(registrar))
val eventChannel = EventChannel(registrar.messenger(), "timerStream")
eventChannel.setStreamHandler(Spotifysdk04Plugin(registrar))
}
}
override fun onMethodCall(call: MethodCall, result: Result) {
if (call.method == "loginAppRemote") {
//...
} else if(call.method == "initEventStream") {
try {
spotifyAppRemote!!.playerApi.subscribeToPlayerState()
.setEventCallback { playerState: PlayerState? ->
Log.d("test", "test24")
var position = playerState!!.playbackPosition.toDouble()
Log.d("playbackPosition1", position.toString())
if(mEventSink != null) {
Log.d("test", "test25")
mEventSink?.success(position)
} else {
Log.d("test", "mEventSink == null")
}
}
} catch (err:Throwable) {
Log.v("initEventStreamError",err.message.toString())
result.success(false)
}
} else {
result.notImplemented()
}
}
override fun onCancel(arguments: Any?) {
mEventSink = null
}
override fun onListen(arguments: Any?, eventSink: EventChannel.EventSink) {
mEventSink = eventSink
}
}

Answer 1

I found a solution:
override fun onListen(p0: Any?, p1: EventChannel.EventSink?) {
mEventSink = p1
Log.d("test", "test1")
if(spotifyAppRemote == null) {
Log.d("test", "test2")
}
val connectionParams = ConnectionParams.Builder(clientId)
.setRedirectUri(redirectUri)
.showAuthView(true)
.build()
SpotifyAppRemote.connect(registrar.context(), connectionParams, object : Connector.ConnectionListener {
override fun onConnected(appRemote: SpotifyAppRemote) {
spotifyAppRemote = appRemote
if(spotifyAppRemote != null) {
Log.d("test", "test3")
spotifyAppRemote!!.playerApi.subscribeToPlayerState()
.setEventCallback { playerState: PlayerState? ->
Log.d("test", "test24")
var position = playerState!!.playbackPosition.toDouble()
Log.d("playbackPosition1", position.toString())
if(mEventSink != null) {
Log.d("test", "test25")
mEventSink?.success(position)
} else {
Log.d("test", "mEventSink == null")
}
}
}
Log.d("Spotify App Remote Login", "Connected!")
}
override fun onFailure(throwable: Throwable) {
Log.e("Spotify App Remote Login", "Error!", throwable)
}
})
}