在颤振上显示空白屏幕的Agora局部视图

Question

我试图集成Agora SDK，我已经能够设置它的功能，但唯一的问题是本地视图是空白的，直到我做热重启，热重启后一切都很好，远程视图工作正常，我一直试图调试这个问题没有用，下面是我的代码。

    import 'dart:async';
    import 'package:flutter/material.dart';
    import 'package:permission_handler/permission_handler.dart';
    
    import 'package:agora_rtc_engine/rtc_engine.dart';
    import 'package:agora_rtc_engine/rtc_local_view.dart' as RtcLocalView;
    import 'package:agora_rtc_engine/rtc_remote_view.dart' as RtcRemoteView;
    
    const appId = "e660ebb529e34d838fedc01ed1a1b5e4";
    const token =
        "006e660ebb529e34d838fedc01ed1a1b5e4IABB69OL6buUPHAgM4dq+hpsHKMLCooStMhXyvSdauF2eNzDPrsAAAAAEADHF4BY49MwYQEAAQDi0zBh";
    
    void main() => runApp(MaterialApp(home: MyApp()));
    
    class MyApp extends StatefulWidget {
      @override
      _MyAppState createState() => _MyAppState();
    }
    
    class _MyAppState extends State {
      int _remoteUid;
      RtcEngine _engine;
    
      @override
      void initState() {
        super.initState();
        initAgora();
      }
    
      Future initAgora() async {
        // retrieve permissions
        await [Permission.microphone, Permission.camera].request();
    
        //create the engine
        _engine = await RtcEngine.create(appId);
        await _engine.enableVideo();
        _engine.setEventHandler(
          RtcEngineEventHandler(
            joinChannelSuccess: (String channel, int uid, int elapsed) {
              print("local user $uid joined");
            },
            userJoined: (int uid, int elapsed) {
              print("remote user $uid joined");
              setState(() {
                _remoteUid = uid;
              });
            },
            userOffline: (int uid, UserOfflineReason reason) {
              print("remote user $uid left channel");
              setState(() {
                _remoteUid = null;
              });
            },
          ),
        );
    
        await _engine.joinChannel(token, "firstchannel", null, 0);
      }
    
      // Create UI with local view and remote view
      @override
      Widget build(BuildContext context) {
        return Scaffold(
          appBar: AppBar(
            title: const Text('Agora Video Call'),
          ),
          body: Stack(
            children: [
              Center(
                child: _remoteVideo(),
              ),
              Align(
                alignment: Alignment.topLeft,
                child: Container(
                  width: 100,
                  height: 100,
                  child: Center(
                    child: RtcLocalView.SurfaceView(),
                  ),
                ),
              ),
            ],
          ),
        );
      }
    
      Widget _renderLocalPreview() {
        return RtcLocalView.SurfaceView();
      }
    
      // Display remote user's video
      Widget _remoteVideo() {
        if (_remoteUid != null) {
          return RtcRemoteView.SurfaceView(uid: _remoteUid);
        } else {
          return Text(
            'Please wait for remote user to join',
            textAlign: TextAlign.center,
          );
        }
      }
    }

   

Answer 1

在与这个问题斗争了一段时间后，我意识到问题来自哪里。在尝试显示本地预览之前，我需要包含一个布尔变量来检查本地用户是否加入了频道。实际上，Agora SDK被设计为仅当用户加入频道时才显示本地预览。

Widget _renderLocalPreview() {
    if (_localUserJoined) {
      return RtcLocalView.SurfaceView();
    } else {
      return Text(
        'Joining Channel, Please wait.....',
        textAlign: TextAlign.center,
      );
    }
  }