fix ANR error (blockingSubscribe in setupWebsocket)

The request seems to cause problems so blockingSubscribe doesn't seem to be a good choice here. This commit will replace blockingSubscribe by subscribe and modify the related code in order to be executed when the request succeeds.
The root cause why the request seems to cause problems may have to be analyzed further.

I was not able to reproduce the ANR without this PR, however the following error was reported on gplay console very often!:

      at jdk.internal.misc.Unsafe.park (Native method)
      at java.util.concurrent.locks.LockSupport.park (LockSupport.java:341)
      at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionNode.block (AbstractQueuedSynchronizer.java:506)
      at java.util.concurrent.ForkJoinPool.unmanagedBlock (ForkJoinPool.java:3466)
      at java.util.concurrent.ForkJoinPool.managedBlock (ForkJoinPool.java:3437)
      at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await (AbstractQueuedSynchronizer.java:1623)
      at java.util.concurrent.LinkedBlockingQueue.take (LinkedBlockingQueue.java:435)
      at io.reactivex.internal.operators.observable.ObservableBlockingSubscribe.subscribe (ObservableBlockingSubscribe.java:56)
      at io.reactivex.Observable.blockingSubscribe (Observable.java:5552)
      at com.nextcloud.talk.chat.ChatActivity.setupWebsocket (ChatActivity.kt:2445)
      at com.nextcloud.talk.chat.ChatActivity.joinRoomWithPassword (ChatActivity.kt:2402)
      at com.nextcloud.talk.chat.ChatActivity.initObservers$lambda$13 (ChatActivity.kt:594)
      at com.nextcloud.talk.chat.ChatActivity.$r8$lambda$QKH5JCFLmCzRMlSJ-EV-m4IW5ig (unavailable)
      at com.nextcloud.talk.chat.ChatActivity$$ExternalSyntheticLambda38.invoke (D8$$SyntheticClass)
      at com.nextcloud.talk.chat.ChatActivity$sam$androidx_lifecycle_Observer$0.onChanged (unavailable:2)
      at androidx.lifecycle.LiveData.considerNotify (LiveData.java:133)
      at androidx.lifecycle.LiveData.dispatchingValue (LiveData.java:151)
      at androidx.lifecycle.LiveData.setValue (LiveData.java:309)
      at androidx.lifecycle.MutableLiveData.setValue (MutableLiveData.java:50)
      at com.nextcloud.talk.chat.viewmodels.ChatViewModel.getCapabilities (ChatViewModel.kt:240)
      at com.nextcloud.talk.chat.ChatActivity$initObservers$1$1.invokeSuspend (ChatActivity.kt:553)
      at com.nextcloud.talk.chat.ChatActivity$initObservers$1$1.invoke (unavailable:8)
      at com.nextcloud.talk.chat.ChatActivity$initObservers$1$1.invoke (unavailable:4)
      at kotlinx.coroutines.flow.FlowKt__TransformKt$onEach$$inlined$unsafeTransform$1$2.emit (Emitters.kt:219)
      at kotlinx.coroutines.flow.FlowKt__ErrorsKt$catchImpl$2.emit (Errors.kt:154)
      at kotlinx.coroutines.flow.FlowKt__TransformKt$onEach$$inlined$unsafeTransform$1$2.emit (Emitters.kt:220)
      at kotlinx.coroutines.flow.SharedFlowImpl.collect$suspendImpl (SharedFlow.kt:392)
      at kotlinx.coroutines.flow.SharedFlowImpl$collect$1.invokeSuspend (unavailable:15)
      at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith (ContinuationImpl.kt:33)
      at kotlinx.coroutines.DispatchedTask.run (DispatchedTask.kt:104)
      at android.os.Handler.handleCallback (Handler.java:938)
      at android.os.Handler.dispatchMessage (Handler.java:99)
      at android.os.Looper.loopOnce (Looper.java:210)
      at android.os.Looper.loop (Looper.java:299)
      at android.app.ActivityThread.main (ActivityThread.java:8168)
      at java.lang.reflect.Method.invoke (Native method)
      at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:556)
      at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:1037)

Signed-off-by: Marcel Hibbe <dev@mhibbe.de>

app/src/main/java/com/nextcloud/talk/chat/ChatActivity.kt

@@ -184,7 +184,9 @@ import com.stfalcon.chatkit.messages.MessageHolders.ContentChecker
 import com.stfalcon.chatkit.messages.MessagesListAdapter
 import com.stfalcon.chatkit.utils.DateFormatter
 import io.reactivex.Observer
+import io.reactivex.android.schedulers.AndroidSchedulers
 import io.reactivex.disposables.Disposable
+import io.reactivex.schedulers.Schedulers
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.delay
@@ -702,14 +704,8 @@ class ChatActivity :
                     logConversationInfos("joinRoomWithPassword#onNext")
 
                     setupWebsocket()
-                    if (webSocketInstance != null) {
-                        webSocketInstance?.joinRoomWithRoomTokenAndSession(
-                            roomToken,
-                            sessionIdAfterRoomJoined,
-                            externalSignalingServer?.federation
-                        )
-                    }
-                    if (startCallFromNotification != null && startCallFromNotification) {
+
+                    if (startCallFromNotification) {
                         startCallFromNotification = false
                         startACall(voiceOnly, false)
                     }
@@ -2477,13 +2473,6 @@ class ChatActivity :
             Log.d(TAG, "sessionID was valid -> skip joinRoom")
 
             setupWebsocket()
-            if (webSocketInstance != null) {
-                webSocketInstance?.joinRoomWithRoomTokenAndSession(
-                    roomToken,
-                    sessionIdAfterRoomJoined,
-                    externalSignalingServer?.federation
-                )
-            }
         }
     }
 
@@ -2519,52 +2508,73 @@ class ChatActivity :
             ncApi.getSignalingSettings(
                 credentials,
                 ApiUtils.getUrlForSignalingSettings(apiVersion, conversationUser!!.baseUrl, roomToken)
-            ).blockingSubscribe(object : Observer<SignalingSettingsOverall> {
-                override fun onSubscribe(d: Disposable) {
-                    // unused atm
-                }
-
-                override fun onNext(signalingSettingsOverall: SignalingSettingsOverall) {
-                    if (signalingSettingsOverall.ocs!!.settings!!.externalSignalingServer == null ||
-                        signalingSettingsOverall.ocs!!.settings!!.externalSignalingServer?.isEmpty() == true
-                    ) {
-                        return
+            )
+                .subscribeOn(Schedulers.io())
+                ?.observeOn(AndroidSchedulers.mainThread())
+                ?.subscribe(object : Observer<SignalingSettingsOverall> {
+                    override fun onSubscribe(d: Disposable) {
+                        // unused atm
                     }
 
-                    externalSignalingServer = ExternalSignalingServer()
-                    externalSignalingServer!!.externalSignalingServer = signalingSettingsOverall.ocs!!.settings!!
-                        .externalSignalingServer
-                    externalSignalingServer!!.externalSignalingTicket = signalingSettingsOverall.ocs!!.settings!!
-                        .externalSignalingTicket
-                    externalSignalingServer!!.federation = signalingSettingsOverall.ocs!!.settings!!.federation
+                    override fun onNext(signalingSettingsOverall: SignalingSettingsOverall) {
+                        if (signalingSettingsOverall.ocs!!.settings!!.externalSignalingServer == null ||
+                            signalingSettingsOverall.ocs!!.settings!!.externalSignalingServer?.isEmpty() == true
+                        ) {
+                            return
+                        }
 
-                    webSocketInstance = WebSocketConnectionHelper.getExternalSignalingInstanceForServer(
-                        externalSignalingServer!!.externalSignalingServer,
-                        conversationUser,
-                        externalSignalingServer!!.externalSignalingTicket,
-                        TextUtils.isEmpty(credentials)
-                    )
-                }
+                        externalSignalingServer = ExternalSignalingServer()
+                        externalSignalingServer!!.externalSignalingServer = signalingSettingsOverall.ocs!!.settings!!
+                            .externalSignalingServer
+                        externalSignalingServer!!.externalSignalingTicket = signalingSettingsOverall.ocs!!.settings!!
+                            .externalSignalingTicket
+                        externalSignalingServer!!.federation = signalingSettingsOverall.ocs!!.settings!!.federation
 
-                override fun onError(e: Throwable) {
-                    Log.e(CallActivity.TAG, e.message, e)
-                }
+                        webSocketInstance = WebSocketConnectionHelper.getExternalSignalingInstanceForServer(
+                            externalSignalingServer!!.externalSignalingServer,
+                            conversationUser,
+                            externalSignalingServer!!.externalSignalingTicket,
+                            TextUtils.isEmpty(credentials)
+                        )
 
-                override fun onComplete() {
-                    // unused atm
-                }
-            })
+                        if (webSocketInstance != null) {
+                            webSocketInstance?.joinRoomWithRoomTokenAndSession(
+                                roomToken,
+                                sessionIdAfterRoomJoined,
+                                externalSignalingServer?.federation
+                            )
+                        }
+
+                        signalingMessageSender = webSocketInstance?.signalingMessageSender
+                        webSocketInstance?.getSignalingMessageReceiver()?.addListener(localParticipantMessageListener)
+                        webSocketInstance?.getSignalingMessageReceiver()?.addListener(conversationMessageListener)
+                    }
+
+                    override fun onError(e: Throwable) {
+                        Log.e(TAG, e.message, e)
+                    }
+
+                    override fun onComplete() {
+                        // unused atm
+                    }
+                })
         } else {
             webSocketInstance = WebSocketConnectionHelper.getWebSocketInstanceForUser(conversationUser!!)
-        }
 
-        if (webSocketInstance == null) {
-            Log.d(TAG, "webSocketInstance not set up. This should only happen when not using the HPB")
-        }
+            if (webSocketInstance != null) {
+                webSocketInstance?.joinRoomWithRoomTokenAndSession(
+                    roomToken,
+                    sessionIdAfterRoomJoined,
+                    null
+                )
 
-        signalingMessageSender = webSocketInstance?.signalingMessageSender
-        webSocketInstance?.getSignalingMessageReceiver()?.addListener(localParticipantMessageListener)
-        webSocketInstance?.getSignalingMessageReceiver()?.addListener(conversationMessageListener)
+                signalingMessageSender = webSocketInstance?.signalingMessageSender
+                webSocketInstance?.getSignalingMessageReceiver()?.addListener(localParticipantMessageListener)
+                webSocketInstance?.getSignalingMessageReceiver()?.addListener(conversationMessageListener)
+            } else {
+                Log.d(TAG, "webSocketInstance not set up. This is only expected when not using the HPB")
+            }
+        }
     }
 
     private fun processCallStartedMessages(chatMessageList: List<ChatMessage>) {