From aac2f5e80cbe629350e1a0eecb61662cce792f26 Mon Sep 17 00:00:00 2001
From: Juan Navarro <juan.navarro@gmx.es>
Date: Fri, 5 Nov 2021 15:46:09 +0100
Subject: [PATCH] android: add stored remote ICE candidates after SDP
 Offer/Answer finishes

ICE candidates are emitted asynchronously, so by the time that SDP messages
have been exchanged, some remote candidates might have already arrived and
stored in temporary variables.

These candidates must be added to the PeerConnection, to make sure that none
is left out!

Corresponds to equivalent code in OpenVidu-Browser:
https://github.com/OpenVidu/openvidu/blob/v2.20.0/openvidu-browser/src/OpenViduInternal/WebRtcPeer/WebRtcPeer.ts#L140-L148
---
 .../openvidu_android/openvidu/Session.java        | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/openvidu-android/app/src/main/java/io/openvidu/openvidu_android/openvidu/Session.java b/openvidu-android/app/src/main/java/io/openvidu/openvidu_android/openvidu/Session.java
index c068af67..cd4c60ee 100644
--- a/openvidu-android/app/src/main/java/io/openvidu/openvidu_android/openvidu/Session.java
+++ b/openvidu-android/app/src/main/java/io/openvidu/openvidu_android/openvidu/Session.java
@@ -13,6 +13,7 @@ import io.openvidu.openvidu_android.websocket.CustomWebSocket;
 import org.webrtc.IceCandidate;
 import org.webrtc.MediaConstraints;
 import org.webrtc.MediaStream;
+import org.webrtc.MediaStreamTrack;
 import org.webrtc.PeerConnection;
 import org.webrtc.PeerConnectionFactory;
 import org.webrtc.RtpReceiver;
@@ -88,6 +89,19 @@ public class Session {
                 super.onIceCandidate(iceCandidate);
                 websocket.onIceCandidate(iceCandidate, localParticipant.getConnectionId());
             }
+
+            @Override
+            public void onSignalingChange(PeerConnection.SignalingState signalingState) {
+                if (PeerConnection.SignalingState.STABLE.equals(signalingState)) {
+                    // SDP Offer/Answer finished. Add stored remote candidates.
+                    Iterator<IceCandidate> it = localParticipant.getIceCandidateList().iterator();
+                    while (it.hasNext()) {
+                        IceCandidate candidate = it.next();
+                        localParticipant.getPeerConnection().addIceCandidate(candidate);
+                        it.remove();
+                    }
+                }
+            }
         });
 
         if (localParticipant.getAudioTrack() != null) {
@@ -132,6 +146,7 @@ public class Session {
             @Override
             public void onSignalingChange(PeerConnection.SignalingState signalingState) {
                 if (PeerConnection.SignalingState.STABLE.equals(signalingState)) {
+                    // SDP Offer/Answer finished. Add stored remote candidates.
                     final RemoteParticipant remoteParticipant = remoteParticipants.get(connectionId);
                     Iterator<IceCandidate> it = remoteParticipant.getIceCandidateList().iterator();
                     while (it.hasNext()) {