fix issue flutter-webrtc#478.

cloudwebrtc · cloudwebrtc · commit a80e742af119 · 2021-02-20T21:16:59.000+08:00
diff --git a/android/src/main/java/com/cloudwebrtc/webrtc/PeerConnectionObserver.java b/android/src/main/java/com/cloudwebrtc/webrtc/PeerConnectionObserver.java
@@ -999,6 +999,9 @@ public void getTransceivers(Result result) {
     }
 
     protected MediaStreamTrack getTransceiversTrack(String trackId) {
+        if(this.configuration.sdpSemantics != PeerConnection.SdpSemantics.UNIFIED_PLAN) {
+            return null;
+        }
         MediaStreamTrack track = null;
         List<RtpTransceiver> transceivers = peerConnection.getTransceivers();
         for (RtpTransceiver transceiver : transceivers) {

Original file line number	Diff line number	Diff line change
`@@ -999,6 +999,9 @@ public void getTransceivers(Result result) {`
`999`	`999`	`}`
`1000`	`1000`
`1001`	`1001`	`protected MediaStreamTrack getTransceiversTrack(String trackId) {`
	`1002`	`+ if(this.configuration.sdpSemantics != PeerConnection.SdpSemantics.UNIFIED_PLAN) {`
	`1003`	`+ return null;`
	`1004`	`+ }`
`1002`	`1005`	`MediaStreamTrack track = null;`
`1003`	`1006`	`List<RtpTransceiver> transceivers = peerConnection.getTransceivers();`
`1004`	`1007`	`for (RtpTransceiver transceiver : transceivers) {`