bug修复：分机呼叫主机，主机接听后迅速挂断，分机出现异常崩溃

callingbed/src/main/java/com/wdkl/app/ncs/callingbed/fragment/SkyCallFragment.kt

@@ -443,7 +443,7 @@ class SkyCallFragment: BaseCallFragment(), CallSession.CallSessionCallback {
                 //远端画面
                 val surfaceView = gEngineKit!!.currentSession.setupRemoteVideo(userId, false)
                 Log.e("dds", "didReceiveRemoteVideoTrack,surfaceView = $surfaceView")
-                if (surfaceView != null) {
+                if (surfaceView != null && fullscreen_video_frame != null) {
                     remoteSurfaceView = surfaceView as SurfaceViewRenderer
                     fullscreen_video_frame.removeAllViews()
                     if (remoteSurfaceView!!.parent != null) {