diff --git a/example/ios/Podfile b/example/ios/Podfile
index 9411102..fab83c6 100644
--- a/example/ios/Podfile
+++ b/example/ios/Podfile
@@ -37,5 +37,8 @@ end
 post_install do |installer|
   installer.pods_project.targets.each do |target|
     flutter_additional_ios_build_settings(target)
+    target.build_configurations.each do |config|
+      config.build_settings['IPHONEOS_DEPLOYMENT_TARGET'] = '10.0'
+    end
   end
 end
diff --git a/example/lib/main.dart b/example/lib/main.dart
index 1784065..d64a2f3 100644
--- a/example/lib/main.dart
+++ b/example/lib/main.dart
@@ -12,8 +12,8 @@ import 'privacy.dart';
 
 void main() {
   runApp(MaterialApp(
-      debugShowCheckedModeBanner: false,
-      home: Platform.isAndroid? Privacy() : Home(),
+    debugShowCheckedModeBanner: false,
+    home: Platform.isAndroid ? Privacy() : Home(),
   ));
 }
 
@@ -34,7 +34,7 @@ class _HomeState extends State<Home> {
   bool _isPublish = false;
   bool _isPublishing = false;
   // The controller for publisher.
-  camera.CameraController _cameraController = null;
+  camera.CameraController _cameraController;
 
   @override
   Widget build(BuildContext context) {
@@ -64,7 +64,9 @@ class _HomeState extends State<Home> {
     _urlController.addListener(_onUserEditUrl);
 
     PackageInfo.fromPlatform().then((info) {
-      setState(() { _info = info; });
+      setState(() {
+        _info = info;
+      });
     }).catchError((e) {
       print('Platform error $e');
     });
@@ -100,7 +102,7 @@ class _HomeState extends State<Home> {
     return _url != null && _url.contains('://');
   }
 
-  void disposeCamera() async {
+  Future disposeCamera() async {
     if (_cameraController == null) {
       return;
     }
@@ -113,8 +115,8 @@ class _HomeState extends State<Home> {
 
   void stopPublish() async {
     await disposeCamera();
-    setState(() { });
-    print('Stop publish url=$_url, publishing=$_isPublishing, controller=${_cameraController?.value.isInitialized}');
+    setState(() {});
+    print('Stop publish url=$_url, publishing=$_isPublishing, controller=${_cameraController.value.isInitialized}');
   }
 
   void _onStartPlayOrPublish(BuildContext context) async {
@@ -123,12 +125,12 @@ class _HomeState extends State<Home> {
       return;
     }
 
-    print('${_isPublishing? "Stop":""} ${_isPublish? "Publish":"Play"} url=$_url, publishing=$_isPublishing');
+    print('${_isPublishing ? "Stop" : ""} ${_isPublish ? "Publish" : "Play"} url=$_url, publishing=$_isPublishing');
 
     // For player.
     if (!_isPublish) {
       Navigator.push(context, MaterialPageRoute(builder: (context) {
-        return _url.startsWith('webrtc://')? WebRTCStreamingPlayer(_url) : LiveStreamingPlayer(_url);
+        return _url.startsWith('webrtc://') ? WebRTCStreamingPlayer(_url) : LiveStreamingPlayer(_url);
       }));
       return;
     }
@@ -160,7 +162,9 @@ class _HomeState extends State<Home> {
 
       _cameraController = camera.CameraController(desc, camera.ResolutionPreset.low);
       _cameraController.addListener(() {
-        setState(() { print('got camera event'); });
+        setState(() {
+          print('got camera event');
+        });
       });
 
       await _cameraController.initialize();
@@ -169,7 +173,9 @@ class _HomeState extends State<Home> {
       await _cameraController.startVideoStreaming(_url, bitrate: 300 * 1000);
       print('Start streaming to $_url');
 
-      setState(() { _isPublishing = true; });
+      setState(() {
+        _isPublishing = true;
+      });
     }
   }
 
@@ -177,7 +183,9 @@ class _HomeState extends State<Home> {
     if (!v) {
       stopPublish();
     }
-    setState(() { _isPublish = v; });
+    setState(() {
+      _isPublish = v;
+    });
   }
 }
 
@@ -189,9 +197,9 @@ class UrlInputDisplay extends StatelessWidget {
   Widget build(BuildContext context) {
     return Container(
       child: TextField(
-        controller: _controller, autofocus: false,
-        decoration: InputDecoration(hintText: 'Please select or input url...')
-      ),
+          controller: _controller,
+          autofocus: false,
+          decoration: InputDecoration(hintText: 'Please select or input url...')),
       padding: EdgeInsets.fromLTRB(5, 0, 5, 0),
     );
   }
@@ -205,80 +213,94 @@ class DemoUrlsDisplay extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Container(child:
-      _isPublish? Column(children: [
-        ListTile(
-          title: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
-            Text('RTMP', style: TextStyle(fontWeight: FontWeight.bold)),
-            Text(flutter_live.FlutterLive.rtmp_publish, style: TextStyle(color: Colors.grey[500])),
-          ]),
-          onTap: () => _onUserSelectUrl(flutter_live.FlutterLive.rtmp_publish), contentPadding: EdgeInsets.zero,
-          leading: Radio(value: flutter_live.FlutterLive.rtmp_publish, groupValue: _url, onChanged: _onUserSelectUrl),
-        ),
-        ListTile(
-          title: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
-            Text('RTMP', style: TextStyle(fontWeight: FontWeight.bold)),
-            Text(flutter_live.FlutterLive.rtmp_publish2, style: TextStyle(color: Colors.grey[500])),
-          ]),
-          onTap: () => _onUserSelectUrl(flutter_live.FlutterLive.rtmp_publish2), contentPadding: EdgeInsets.zero,
-          leading: Radio(value: flutter_live.FlutterLive.rtmp_publish2, groupValue: _url, onChanged: _onUserSelectUrl),
-        ),
-      ],) : Column(children: [
-        ListTile(
-          title: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
-            Text('RTMP', style: TextStyle(fontWeight: FontWeight.bold)),
-            Text(flutter_live.FlutterLive.rtmp, style: TextStyle(color: Colors.grey[500])),
-          ]),
-          onTap: () => _onUserSelectUrl(flutter_live.FlutterLive.rtmp), contentPadding: EdgeInsets.zero,
-          leading: Radio(value: flutter_live.FlutterLive.rtmp, groupValue: _url, onChanged: _onUserSelectUrl),
-        ),
-        ListTile(
-          title: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
-            Text('HLS', style: TextStyle(fontWeight: FontWeight.bold)),
-            Text(flutter_live.FlutterLive.hls, style: TextStyle(color: Colors.grey[500])),
-          ]),
-          onTap: () => _onUserSelectUrl(flutter_live.FlutterLive.hls), contentPadding: EdgeInsets.zero,
-          leading: Radio(value: flutter_live.FlutterLive.hls, groupValue: _url, onChanged: _onUserSelectUrl),
-        ),
-        ListTile(
-          title: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
-            Text('HTTP-FLV', style: TextStyle(fontWeight: FontWeight.bold)),
-            Text(flutter_live.FlutterLive.flv, style: TextStyle(color: Colors.grey[500])),
-          ]),
-          onTap: () => _onUserSelectUrl(flutter_live.FlutterLive.flv), contentPadding: EdgeInsets.zero,
-          leading: Radio(value: flutter_live.FlutterLive.flv, groupValue: _url, onChanged: _onUserSelectUrl),
-        ),
-        ListTile(
-          title: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
-            Text('WebRTC', style: TextStyle(fontWeight: FontWeight.bold)),
-            Text(flutter_live.FlutterLive.rtc, style: TextStyle(color: Colors.grey[500], fontSize: 15)),
-          ]),
-          onTap: () => _onUserSelectUrl(flutter_live.FlutterLive.rtc), contentPadding: EdgeInsets.zero,
-          leading: Radio(value: flutter_live.FlutterLive.rtc, groupValue: _url, onChanged: _onUserSelectUrl),
-        ),
-        ListTile(
-          title: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
-            Text('HTTPS-FLV', style: TextStyle(fontWeight: FontWeight.bold)),
-            Container(
-              child: Text(flutter_live.FlutterLive.flvs, style: TextStyle(color: Colors.grey[500], fontSize: 15)),
-              padding: EdgeInsets.only(top: 3, bottom:3),
-            ),
-          ]),
-          onTap: () => _onUserSelectUrl(flutter_live.FlutterLive.flvs), contentPadding: EdgeInsets.zero,
-          leading: Radio(value: flutter_live.FlutterLive.flvs, groupValue: _url, onChanged: _onUserSelectUrl),
-        ),
-        ListTile(
-          title: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
-            Text('HTTPS-HLS', style: TextStyle(fontWeight: FontWeight.bold)),
-            Container(
-              child: Text(flutter_live.FlutterLive.hlss, style: TextStyle(color: Colors.grey[500], fontSize: 14)),
-              padding: EdgeInsets.only(top: 3, bottom: 3),
-            ),
-          ]),
-          onTap: () => _onUserSelectUrl(flutter_live.FlutterLive.hlss), contentPadding: EdgeInsets.zero,
-          leading: Radio(value: flutter_live.FlutterLive.hlss, groupValue: _url, onChanged: _onUserSelectUrl),
-        ),
-      ]),
+    return Container(
+      child: _isPublish
+          ? Column(
+              children: [
+                ListTile(
+                  title: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
+                    Text('RTMP', style: TextStyle(fontWeight: FontWeight.bold)),
+                    Text(flutter_live.FlutterLive.rtmp_publish, style: TextStyle(color: Colors.grey[500])),
+                  ]),
+                  onTap: () => _onUserSelectUrl(flutter_live.FlutterLive.rtmp_publish),
+                  contentPadding: EdgeInsets.zero,
+                  leading: Radio(
+                      value: flutter_live.FlutterLive.rtmp_publish, groupValue: _url, onChanged: _onUserSelectUrl),
+                ),
+                ListTile(
+                  title: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
+                    Text('RTMP', style: TextStyle(fontWeight: FontWeight.bold)),
+                    Text(flutter_live.FlutterLive.rtmp_publish2, style: TextStyle(color: Colors.grey[500])),
+                  ]),
+                  onTap: () => _onUserSelectUrl(flutter_live.FlutterLive.rtmp_publish2),
+                  contentPadding: EdgeInsets.zero,
+                  leading: Radio(
+                      value: flutter_live.FlutterLive.rtmp_publish2, groupValue: _url, onChanged: _onUserSelectUrl),
+                ),
+              ],
+            )
+          : Column(children: [
+              ListTile(
+                title: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
+                  Text('RTMP', style: TextStyle(fontWeight: FontWeight.bold)),
+                  Text(flutter_live.FlutterLive.rtmp, style: TextStyle(color: Colors.grey[500])),
+                ]),
+                onTap: () => _onUserSelectUrl(flutter_live.FlutterLive.rtmp),
+                contentPadding: EdgeInsets.zero,
+                leading: Radio(value: flutter_live.FlutterLive.rtmp, groupValue: _url, onChanged: _onUserSelectUrl),
+              ),
+              ListTile(
+                title: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
+                  Text('HLS', style: TextStyle(fontWeight: FontWeight.bold)),
+                  Text(flutter_live.FlutterLive.hls, style: TextStyle(color: Colors.grey[500])),
+                ]),
+                onTap: () => _onUserSelectUrl(flutter_live.FlutterLive.hls),
+                contentPadding: EdgeInsets.zero,
+                leading: Radio(value: flutter_live.FlutterLive.hls, groupValue: _url, onChanged: _onUserSelectUrl),
+              ),
+              ListTile(
+                title: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
+                  Text('HTTP-FLV', style: TextStyle(fontWeight: FontWeight.bold)),
+                  Text(flutter_live.FlutterLive.flv, style: TextStyle(color: Colors.grey[500])),
+                ]),
+                onTap: () => _onUserSelectUrl(flutter_live.FlutterLive.flv),
+                contentPadding: EdgeInsets.zero,
+                leading: Radio(value: flutter_live.FlutterLive.flv, groupValue: _url, onChanged: _onUserSelectUrl),
+              ),
+              ListTile(
+                title: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
+                  Text('WebRTC', style: TextStyle(fontWeight: FontWeight.bold)),
+                  Text(flutter_live.FlutterLive.rtc, style: TextStyle(color: Colors.grey[500], fontSize: 15)),
+                ]),
+                onTap: () => _onUserSelectUrl(flutter_live.FlutterLive.rtc),
+                contentPadding: EdgeInsets.zero,
+                leading: Radio(value: flutter_live.FlutterLive.rtc, groupValue: _url, onChanged: _onUserSelectUrl),
+              ),
+              ListTile(
+                title: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
+                  Text('HTTPS-FLV', style: TextStyle(fontWeight: FontWeight.bold)),
+                  Container(
+                    child: Text(flutter_live.FlutterLive.flvs, style: TextStyle(color: Colors.grey[500], fontSize: 15)),
+                    padding: EdgeInsets.only(top: 3, bottom: 3),
+                  ),
+                ]),
+                onTap: () => _onUserSelectUrl(flutter_live.FlutterLive.flvs),
+                contentPadding: EdgeInsets.zero,
+                leading: Radio(value: flutter_live.FlutterLive.flvs, groupValue: _url, onChanged: _onUserSelectUrl),
+              ),
+              ListTile(
+                title: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
+                  Text('HTTPS-HLS', style: TextStyle(fontWeight: FontWeight.bold)),
+                  Container(
+                    child: Text(flutter_live.FlutterLive.hlss, style: TextStyle(color: Colors.grey[500], fontSize: 14)),
+                    padding: EdgeInsets.only(top: 3, bottom: 3),
+                  ),
+                ]),
+                onTap: () => _onUserSelectUrl(flutter_live.FlutterLive.hlss),
+                contentPadding: EdgeInsets.zero,
+                leading: Radio(value: flutter_live.FlutterLive.hlss, groupValue: _url, onChanged: _onUserSelectUrl),
+              ),
+            ]),
     );
   }
 }
@@ -289,7 +311,8 @@ class ControlDisplay extends StatelessWidget {
   final bool _isPubslish;
   final bool _isPublishing;
   final ValueChanged<bool> _onSwitchPublish;
-  ControlDisplay(this._urlAvailable, this._onStartPlayOrPublish, this._isPubslish, this._isPublishing, this._onSwitchPublish);
+  ControlDisplay(
+      this._urlAvailable, this._onStartPlayOrPublish, this._isPubslish, this._isPublishing, this._onSwitchPublish);
 
   @override
   Widget build(BuildContext context) {
@@ -297,7 +320,7 @@ class ControlDisplay extends StatelessWidget {
       if (_isPublishing) {
         return 'Stop';
       }
-      return _isPubslish? 'Publish' : 'Play';
+      return _isPubslish ? 'Publish' : 'Play';
     };
 
     return Row(
@@ -311,9 +334,9 @@ class ControlDisplay extends StatelessWidget {
         ),
         Container(
           width: 120,
-          child:ElevatedButton(
+          child: ElevatedButton(
             child: Text(actionText()),
-            onPressed: _urlAvailable? _onStartPlayOrPublish : null,
+            onPressed: _urlAvailable ? _onStartPlayOrPublish : null,
           ),
         ),
       ],
@@ -337,15 +360,16 @@ class CameraDisplay extends StatelessWidget {
     }
 
     if (!_cameraController.value.isInitialized) {
-      return Container(child: Center(child: Text(
-        'Camera not available', style: TextStyle(color: Colors.red[500]),
+      return Container(
+          child: Center(
+              child: Text(
+        'Camera not available',
+        style: TextStyle(color: Colors.red[500]),
       )));
     }
 
     return AspectRatio(
-        aspectRatio: _cameraController.value.aspectRatio,
-        child: camera.CameraPreview(_cameraController)
-    );
+        aspectRatio: _cameraController.value.aspectRatio, child: camera.CameraPreview(_cameraController));
   }
 }
 
@@ -361,10 +385,11 @@ class PlatformDisplay extends StatelessWidget {
         Text.rich(
           TextSpan(
             text: 'SRS/v${_info.version}+${_info.buildNumber}',
-            recognizer: TapGestureRecognizer() ..onTap = () async {
-              SharedPreferences prefs = await SharedPreferences.getInstance();
-              prefs.setBool("login", false);
-            },
+            recognizer: TapGestureRecognizer()
+              ..onTap = () async {
+                SharedPreferences prefs = await SharedPreferences.getInstance();
+                prefs.setBool("login", false);
+              },
           ),
         ),
       ],
@@ -388,9 +413,7 @@ class _LiveStreamingPlayerState extends State<LiveStreamingPlayer> {
     return Scaffold(
       appBar: AppBar(title: Text('SRS Live Streaming')),
       body: fijkplayer.FijkView(
-          player: _player.fijk, panelBuilder: fijkplayer.fijkPanel2Builder(),
-          fsFit: fijkplayer.FijkFit.fill
-      ),
+          player: _player.fijk, panelBuilder: fijkplayer.fijkPanel2Builder(), fsFit: fijkplayer.FijkFit.fill),
     );
   }
 
@@ -430,9 +453,9 @@ class _WebRTCStreamingPlayerState extends State<WebRTCStreamingPlayer> {
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(title: Text('SRS WebRTC Streaming')),
-      body: GestureDetector(onTap: _switchLoudspeaker, child: Container(
-          child: webrtc.RTCVideoView(_video), decoration: BoxDecoration(color: Colors.grey[500])
-      )),
+      body: GestureDetector(
+          onTap: _switchLoudspeaker,
+          child: Container(child: webrtc.RTCVideoView(_video), decoration: BoxDecoration(color: Colors.grey[500]))),
     );
   }
 
@@ -449,7 +472,9 @@ class _WebRTCStreamingPlayerState extends State<WebRTCStreamingPlayer> {
     // Render stream when got remote stream.
     _player.onRemoteStream = (webrtc.MediaStream stream) {
       // @remark It's very important to use setState to set the srcObject and notify render.
-      setState(() { _video.srcObject = stream; });
+      setState(() {
+        _video.srcObject = stream;
+      });
     };
 
     // Auto start play WebRTC streaming.
@@ -457,7 +482,7 @@ class _WebRTCStreamingPlayerState extends State<WebRTCStreamingPlayer> {
   }
 
   void _switchLoudspeaker() {
-    print('setSpeakerphoneOn: $_loudspeaker(${_loudspeaker? "Loudspeaker":"Earpiece"})');
+    print('setSpeakerphoneOn: $_loudspeaker(${_loudspeaker ? "Loudspeaker" : "Earpiece"})');
     flutter_live.FlutterLive.setSpeakerphoneOn(_loudspeaker);
     _loudspeaker = !_loudspeaker;
   }
@@ -469,4 +494,3 @@ class _WebRTCStreamingPlayerState extends State<WebRTCStreamingPlayer> {
     _player.dispose();
   }
 }
-
diff --git a/lib/flutter_live.dart b/lib/flutter_live.dart
index 6cd7607..ab3133a 100644
--- a/lib/flutter_live.dart
+++ b/lib/flutter_live.dart
@@ -110,9 +110,10 @@ class RealtimePlayer {
 ///   streamUrl: "webrtc://d.ossrs.net:11985/live/livestream"
 class WebRTCUri {
   /// The api server url for WebRTC streaming.
-  String api;
+  String api = "";
+
   /// The stream url to play or publish.
-  String streamUrl;
+  String streamUrl = "";
 
   /// Parse the url to WebRTC uri.
   static WebRTCUri parse(String url) {
@@ -120,21 +121,21 @@ class WebRTCUri {
 
     var schema = 'https'; // For native, default to HTTPS
     if (uri.queryParameters.containsKey('schema')) {
-      schema = uri.queryParameters['schema'];
+      schema = uri.queryParameters['schema']!;
     } else {
       schema = 'https';
     }
 
-    var port = (uri.port > 0)? uri.port : 443;
+    var port = (uri.port > 0) ? uri.port : 443;
     if (schema == 'https') {
-      port = (uri.port > 0)? uri.port : 443;
+      port = (uri.port > 0) ? uri.port : 443;
     } else if (schema == 'http') {
-      port = (uri.port > 0)? uri.port : 1985;
+      port = (uri.port > 0) ? uri.port : 1985;
     }
 
     var api = '/rtc/v1/play/';
     if (uri.queryParameters.containsKey('play')) {
-      api = uri.queryParameters['play'];
+      api = uri.queryParameters['play']!;
     }
 
     var apiParams = [];
@@ -145,7 +146,7 @@ class WebRTCUri {
     }
 
     var apiUrl = '${schema}://${uri.host}:${port}${api}';
-    if (!apiParams.isEmpty) {
+    if (apiParams.isEmpty) {
       apiUrl += '?' + apiParams.join('&');
     }
 
@@ -159,8 +160,8 @@ class WebRTCUri {
 
 /// A WebRTC player, using [flutter_webrtc](https://pub.dev/packages/flutter_webrtc)
 class WebRTCPlayer {
-  webrtc.AddStreamCallback _onRemoteStream;
-  webrtc.RTCPeerConnection _pc;
+  webrtc.AddStreamCallback? _onRemoteStream;
+  webrtc.RTCPeerConnection? _pc;
 
   /// When got a remote stream.
   set onRemoteStream(webrtc.AddStreamCallback v) {
@@ -168,14 +169,13 @@ class WebRTCPlayer {
   }
 
   /// Initialize the player.
-  void initState() {
-  }
+  void initState() {}
 
   /// Start play a url.
   /// [url] must a path parsed by [WebRTCUri.parse] in https://github.com/rtcdn/rtcdn-draft
   Future<void> play(String url) async {
     if (_pc != null) {
-      await _pc.close();
+      await _pc!.close();
     }
 
     // Create the peer connection.
@@ -187,36 +187,36 @@ class WebRTCPlayer {
     print('WebRTC: createPeerConnection done');
 
     // Setup the peer connection.
-    _pc.onAddStream = (webrtc.MediaStream stream) {
+    _pc!.onAddStream = (webrtc.MediaStream stream) {
       print('WebRTC: got stream ${stream.id}');
       if (_onRemoteStream == null) {
         print('Warning: Stream ${stream.id} is leak');
         return;
       }
-      _onRemoteStream(stream);
+      _onRemoteStream!(stream);
     };
 
-    _pc.addTransceiver(
-        kind: webrtc.RTCRtpMediaType.RTCRtpMediaTypeAudio,
-        init: webrtc.RTCRtpTransceiverInit(direction: webrtc.TransceiverDirection.RecvOnly),
+    _pc!.addTransceiver(
+      kind: webrtc.RTCRtpMediaType.RTCRtpMediaTypeAudio,
+      init: webrtc.RTCRtpTransceiverInit(direction: webrtc.TransceiverDirection.RecvOnly),
     );
-    _pc.addTransceiver(
+    _pc!.addTransceiver(
       kind: webrtc.RTCRtpMediaType.RTCRtpMediaTypeVideo,
       init: webrtc.RTCRtpTransceiverInit(direction: webrtc.TransceiverDirection.RecvOnly),
     );
     print('WebRTC: Setup PC done, A|V RecvOnly');
 
     // Start SDP handshake.
-    webrtc.RTCSessionDescription offer = await _pc.createOffer({
+    webrtc.RTCSessionDescription offer = await _pc!.createOffer({
       'mandatory': {'OfferToReceiveAudio': true, 'OfferToReceiveVideo': true},
     });
-    await _pc.setLocalDescription(offer);
-    print('WebRTC: createOffer, ${offer.type} is ${offer.sdp.replaceAll('\n', '\\n').replaceAll('\r', '\\r')}');
+    await _pc!.setLocalDescription(offer);
+    print('WebRTC: createOffer, ${offer.type} is ${offer.sdp?.replaceAll('\n', '\\n').replaceAll('\r', '\\r')}');
 
-    webrtc.RTCSessionDescription answer = await _handshake(url, offer.sdp);
-    print('WebRTC: got ${answer.type} is ${answer.sdp.replaceAll('\n', '\\n').replaceAll('\r', '\\r')}');
+    webrtc.RTCSessionDescription answer = await _handshake(url, offer.sdp ?? "");
+    print('WebRTC: got ${answer.type} is ${answer.sdp?.replaceAll('\n', '\\n').replaceAll('\r', '\\r')}');
 
-    await _pc.setRemoteDescription(answer);
+    await _pc!.setRemoteDescription(answer);
   }
 
   /// Handshake to exchange SDP, send offer and got answer.
@@ -261,8 +261,7 @@ class WebRTCPlayer {
   /// Dispose the player.
   void dispose() {
     if (_pc != null) {
-      _pc.close();
+      _pc!.close();
     }
   }
 }
-
diff --git a/pubspec.yaml b/pubspec.yaml
index 4d7c961..9345643 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -2,17 +2,28 @@ name: flutter_live
 version: 1.0.17
 description: Live streaming player, iOS+Android, RTMP/HTTP-FLV/HLS/WebRTC, by Flutter+SRS.
 homepage: https://github.com/ossrs/flutter_live
+publish_to: 'none'
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
-  flutter: ">=1.20.0 <2.0.0"
+  sdk: ">=2.13.0 <3.0.0"
 
 dependencies:
   flutter:
     sdk: flutter
-  fijkplayer: ^0.8.8
-  flutter_webrtc: ^0.6.3
-  camera_with_rtmp: ^0.3.2
+  fijkplayer: ^0.10.0
+  flutter_webrtc: ^0.6.5
+  rtmp_publisher: 
+    git: 
+      url: git@github.com:hetao29/flutter_rtmp_publisher.git  
+      ref: 172c092a9d23aab1d873a67963d625a98ab7c21f
+  #camera_with_rtmp:
+    #path: ../flutter_rtmppublisher_hetao29
+  #  git: 
+  #    url: git@github.com:babulpatel1309/flutter_rtmppublisher.git
+
+    #git:
+    #  url: https://github.com/hetao29/flutter_rtmppublisher.git
+    #  ref: 79010b3724574f79b60974b64982aad751b56803
 
 dev_dependencies:
   flutter_test: