Support custom MediaStream for call/answer.

Author: cloudwebrtc

example/lib/src/callscreen.dart

@@ -199,8 +199,22 @@ class _MyCallScreenWidget extends State<CallScreenWidget>
     _timer.cancel();
   }
 
-  void _handleAccept() {
-    call.answer(helper.buildCallOptions());
+  void _handleAccept() async {
+    final mediaConstraints = <String, dynamic>{'audio': true, 'video': true};
+    MediaStream mediaStream;
+
+    if (kIsWeb) {
+      mediaStream =
+          await navigator.mediaDevices.getDisplayMedia(mediaConstraints);
+      mediaConstraints['video'] = false;
+      MediaStream userStream =
+          await navigator.mediaDevices.getUserMedia(mediaConstraints);
+      mediaStream.addTrack(userStream.getAudioTracks()[0], addToNative: true);
+    } else {
+      mediaStream = await navigator.mediaDevices.getUserMedia(mediaConstraints);
+    }
+
+    call.answer(helper.buildCallOptions(), mediaStream: mediaStream);
   }
 
   void _switchCamera() {

example/lib/src/dialpad.dart

@@ -1,6 +1,8 @@
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:sip_ua/sip_ua.dart';
 import 'package:shared_preferences/shared_preferences.dart';
+import 'package:flutter_webrtc/flutter_webrtc.dart';
 
 import 'widgets/action_button.dart';
 
@@ -41,7 +43,8 @@ class _MyDialPadWidget extends State<DialPadWidget>
     helper.addSipUaHelperListener(this);
   }
 
-  Widget _handleCall(BuildContext context, [bool voiceonly = false]) {
+  Future<Widget> _handleCall(BuildContext context,
+      [bool voiceonly = false]) async {
     var dest = _textController.text;
     if (dest == null || dest.isEmpty) {
       showDialog<Null>(
@@ -64,7 +67,23 @@ class _MyDialPadWidget extends State<DialPadWidget>
       );
       return null;
     }
-    helper.call(dest, voiceonly);
+
+    final mediaConstraints = <String, dynamic>{'audio': true, 'video': true};
+
+    MediaStream mediaStream;
+
+    if (kIsWeb) {
+      mediaStream =
+          await navigator.mediaDevices.getDisplayMedia(mediaConstraints);
+      mediaConstraints['video'] = false;
+      MediaStream userStream =
+          await navigator.mediaDevices.getUserMedia(mediaConstraints);
+      mediaStream.addTrack(userStream.getAudioTracks()[0], addToNative: true);
+    } else {
+      mediaStream = await navigator.mediaDevices.getUserMedia(mediaConstraints);
+    }
+    
+    helper.call(dest, voiceonly: voiceonly, mediaStream: mediaStream);
     _preferences.setString('dest', dest);
     return null;
   }

lib/src/rtc_session.dart

@@ -590,6 +590,7 @@ class RTCSession extends EventManager {
     // A local MediaStream is given, use it.
     if (mediaStream != null) {
       stream = mediaStream;
+      emit(EventStream(session: this, originator: 'local', stream: stream));
     }
     // Audio and/or video requested, prompt getUserMedia.
     else if (mediaConstraints['audio'] != null ||
@@ -2195,6 +2196,7 @@ class RTCSession extends EventManager {
     // A stream is given, var the app set events such as 'peerconnection' and 'connecting'.
     if (mediaStream != null) {
       stream = mediaStream;
+      emit(EventStream(session: this, originator: 'local', stream: stream));
     } // Request for user media access.
     else if (mediaConstraints['audio'] != null ||
         mediaConstraints['video'] != null) {

lib/src/sip_ua_helper.dart

@@ -69,9 +69,13 @@ class SIPUAHelper extends EventManager {
   }
 
   Future<bool> call(String target,
-      [bool voiceonly = false, MediaStream mediaStream = null]) async {
+      {bool voiceonly = false, MediaStream mediaStream = null}) async {
     if (_ua != null && _ua.isConnected()) {
-      _ua.call(target, buildCallOptions(voiceonly));
+      Map<String, Object> options = buildCallOptions(voiceonly);
+      if (mediaStream != null) {
+        options['mediaStream'] = mediaStream;
+      }
+      _ua.call(target, options);
       return true;
     } else {
       logger.error(
@@ -387,8 +391,11 @@ class Call {
   String get id => _id;
   CallStateEnum state;
 
-  void answer(Map<String, Object> options) {
+  void answer(Map<String, Object> options, {MediaStream mediaStream = null}) {
     assert(_session != null, 'ERROR(answer): rtc session is invalid!');
+    if (mediaStream != null) {
+      options['mediaStream'] = mediaStream;
+    }
     _session.answer(options);
   }