Fix remote participants display with both video and screen share

ParticipantDisplayItems are not associated to a full participant but to
each of the single connections that the participant may have (video and
screen). However, when they are added to the map only the session ID is
used as key. Due to this when a participant starts a screen share the
ParticipantDisplayItem for the screen share overwrites the item for the
video, and once the screen share is stopped the old item is not
restored. Moreover, if a participant is already sharing a screen when
the local participant joins whether the video or the screen share is
shown is undefined and depends on which connection is established first.

To solve that the ParticipantDisplayItems are now associated with both
the session ID and the video stream type ("video" or "screen"). Due to
this both the video and the screen share of the remote participant are
shown in the grid view; in the future it might be better to only show
the screen share, or allow switching between screen share and video, or
show the screen share in full screen and hide the grid... but for now,
as a quick fix, this is good enough :-)

Signed-off-by: Daniel Calviño Sánchez <danxuliu@gmail.com>

app/src/main/java/com/nextcloud/talk/activities/CallActivity.java

@@ -2087,8 +2087,9 @@ public class CallActivity extends CallBaseActivity {
         if (!(peerConnectionWrappers = getPeerConnectionWrapperListForSessionId(sessionId)).isEmpty()) {
             for (PeerConnectionWrapper peerConnectionWrapper : peerConnectionWrappers) {
                 if (peerConnectionWrapper.getSessionId().equals(sessionId)) {
-                    if (VIDEO_STREAM_TYPE_SCREEN.equals(peerConnectionWrapper.getVideoStreamType()) || !justScreen) {
-                        runOnUiThread(() -> removeMediaStream(sessionId));
+                    String videoStreamType = peerConnectionWrapper.getVideoStreamType();
+                    if (VIDEO_STREAM_TYPE_SCREEN.equals(videoStreamType) || !justScreen) {
+                        runOnUiThread(() -> removeMediaStream(sessionId, videoStreamType));
                         deletePeerConnection(peerConnectionWrapper);
                     }
                 }
@@ -2096,9 +2097,9 @@ public class CallActivity extends CallBaseActivity {
         }
     }
 
-    private void removeMediaStream(String sessionId) {
+    private void removeMediaStream(String sessionId, String videoStreamType) {
         Log.d(TAG, "removeMediaStream");
-        participantDisplayItems.remove(sessionId);
+        participantDisplayItems.remove(sessionId + "-" + videoStreamType);
 
         if (!isDestroyed()) {
             initGridAdapter();
@@ -2409,7 +2410,7 @@ public class CallActivity extends CallBaseActivity {
                                                                                    videoStreamType,
                                                                                    videoStreamEnabled,
                                                                                    rootEglBase);
-        participantDisplayItems.put(session, participantDisplayItem);
+        participantDisplayItems.put(session + "-" + videoStreamType, participantDisplayItem);
 
         initGridAdapter();
     }