class CallPage extends StatefulWidget {
  final String cid;
  final int uid;

  CallPage({Key? key, required this.cid, required this.uid});

  @override
  _CallPageState createState() {
    return _CallPageState();
  }
}

class _CallPageState extends State<CallPage>
    with
        NERtcVideoRendererEventListener,
        NERtcChannelEventCallback,
        NERtcAudioMixingEventCallback,
        NERtcAudioEffectEventCallback,
        NERtcStatsEventCallback,
        NERtcDeviceEventCallback,
        NERtcLiveTaskCallback {
  late Settings _settings;
  NERtcEngine _engine = NERtcEngine.instance;
  List<_UserSession> _remoteSessions = [];
  _UserSession? _localSession;
  _UserSession? _localSubStreamSession;
  
  bool isAudioEnabled = false;
  bool isVideoEnabled = false;
  bool isFrontCamera = true;
  bool isFrontCameraMirror = true;
  bool isSpeakerphoneOn = false;

  bool forceSubAndUnsubVideo = false;
  final foregroundServiceChannel = const MethodChannel(
      'com.netease.nertc_core.nertc_core_example.foreground_service');

  @override
  void initState() {
    super.initState();
    print('start call: uid=${widget.uid}, cid=${widget.cid}');
    _initSettings().then((value) => _initRtcEngine());
    if (Platform.isAndroid) {
      foregroundServiceChannel.invokeMethod('startForegroundService');
    }
  }

  @override
  Widget build(BuildContext context) {
    screenSize = MediaQuery.of(context).size;

    return WillPopScope(
      child: GestureDetector(
        onTap: () {
          setState(() {
            showControlPanel = !showControlPanel;
          });
        },
        child: Scaffold(
          appBar: AppBar(
            automaticallyImplyLeading: false,
            centerTitle: true,
            title: Text(widget.cid),
          ),
          body: buildCallingWidget(context),
        ),
      ),
      // ignore: missing_return
      onWillPop: () {
        _requestPop();
        return Future.value(true);
      },
    );
  }

  Widget buildCallingWidget(BuildContext context) {
    return Stack(children: <Widget>[
      buildVideoViews(context),
      if (showControlPanel) buildControlPanel(context)
    ]);
  }

  Widget buildControlPanel(BuildContext context) {
    return Container(
        height: 40,
        child: Row(
          children: [
            Expanded(
                child: buildControlButton(
              () {
                bool audioEnabled = !isAudioEnabled;
                _engine.enableLocalAudio(audioEnabled).then((value) {
                  if (value == 0) {
                    setState(() {
                      isAudioEnabled = audioEnabled;
                    });
                  }
                });
              },
              Text(
                isAudioEnabled ? '关闭语音' : '打开语音',
                style: TextStyle(fontSize: 12),
              ),
            )),
            Expanded(
                child: buildControlButton(
              () {
                bool videoEnabled = !isVideoEnabled;
                _engine.enableLocalVideo(videoEnabled).then((value) {
                  if (value == 0) {
                    setState(() {
                      isVideoEnabled = videoEnabled;
                    });
                  }
                });
              },
              Text(
                isVideoEnabled ? '关闭视频' : '打开视频',
                style: TextStyle(fontSize: 12),
              ),
            )),
            Expanded(
                child: buildControlButton(
              () {
                _engine.deviceManager.switchCamera().then((value) {
                  if (value == 0) {
                    isFrontCamera = !isFrontCamera;
                    updateLocalMirror();
                  }
                });
              },
              Text(
                '切换摄像头',
                style: TextStyle(fontSize: 12),
              ),
            )),
            Expanded(
                child: buildControlButton(
              () {
                bool speakerphoneOn = !isSpeakerphoneOn;
                _engine.deviceManager
                    .setSpeakerphoneOn(speakerphoneOn)
                    .then((value) {
                  if (value == 0) {
                    setState(() {
                      isSpeakerphoneOn = speakerphoneOn;
                    });
                  }
                });
              },
              Text(
                isSpeakerphoneOn ? '关闭扬声器' : '打开扬声器',
                style: TextStyle(fontSize: 12),
              ),
            )),
          ],
        ));
  }

  Widget buildVideoViews(BuildContext context) {
    final sessions = [
      if (_localSession != null) _localSession!,
      if (_localSubStreamSession != null) _localSubStreamSession!,
      ..._remoteSessions,
    ];

    return OrientationBuilder(
      builder: (BuildContext context, Orientation orientation) {
        final isLandscape = orientation == Orientation.landscape;
        return GridView.builder(
          scrollDirection: isLandscape ? Axis.horizontal : Axis.vertical,
          gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
            crossAxisCount: isLandscape ? 1 : 3,
            childAspectRatio: isLandscape ? 16 / 9 : 9 / 16,
            crossAxisSpacing: 2.0,
            mainAxisSpacing: 2.0,
          ),
          itemCount: sessions.length,
          itemBuilder: (BuildContext context, int index) {
            return buildVideoView(context, sessions[index]);
          },
        );
      },
    );
  }

  Widget buildVideoView(BuildContext context, _UserSession session) {
    return Container(
      child: Stack(
        children: [
          NERtcVideoView(
            uid: session.uid == widget.uid ? null : session.uid,
            subStream: session.subStream,
            mirrorListenable: session.mirror,
            rendererEventLister: this,
          ),
          Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              Text(
                session.subStream ? '${session.uid} @ Sub' : '${session.uid}',
                style: TextStyle(color: Colors.red, fontSize: 10),
              )
            ],
          )
        ],
      ),
    );
  }

 NERtcEngine _engine = NERtcEngine.instance;
//初始化SDK
 await _engine
        .create(
            appKey: Config.APP_KEY,
            channelEventCallback: this,
            options: options)

·//添加callback回调
    // _engine.setStatsEventCallback(this);
    _engine.audioMixingManager.setEventCallback(this);
    _engine.audioEffectManager.setEventCallback(this);
    _engine.deviceManager.setEventCallback(this);
    _engine.setLiveTaskEventCallback(this);
    _engine.setEventCallback(this);
  
//设置本地摄像头的采集偏好等配置
    final config = NERtcCameraCaptureConfig.manual(640, 360);
    await _engine.setCameraCaptureConfig(config);


//设置本地视频参数
NERtcVideoConfig config = NERtcVideoConfig();
    config.videoProfile = _settings.videoProfile;
    config.frameRate = _settings.videoFrameRate;
    config.degradationPrefer = _settings.degradationPreference;
    config.frontCamera = _settings.frontFacingCamera;
    config.videoCropMode = _settings.videoCropMode;
    await _engine.setLocalVideoConfig(config);

//加入房间前提前设置好音视频开启状态
if (Platform.isIOS) {
      await _engine.setAudioSessionOperationRestriction(
          NERtcAudioSessionOperationRestriction
              .values[_settings.audioSessionRestriction]);
    }
    await _engine.setAudioProfile(
        NERtcAudioProfile.values[_settings.audioProfile],
        NERtcAudioScenario.values[_settings.audioScenario]);
    await _engine.enableLocalAudio(isAudioEnabled);
    await _engine.enableLocalVideo(isVideoEnabled);


//加入房间
long yourUid = 1234567;//同一个房间不允许相同uid
_engine.joinChannel('', cid, yourUid)

//结束通话
_engine.leaveChannel();

//释放SDK
_engine.release();

实现基础的音视频通话，建议您参考 xml 界面的示例代码在界面上添加以下控件。

• 房间 ID
• 用户昵称
• 本端视频窗口
• 远端视频窗口
• 麦克风按钮
• 摄像头按钮
• 结束通话按钮

效果图如下图所示。