颤动摄像头0.8.1在流媒体播放时闪光

Question

有没有办法在flutter中使用0.8.1摄像头从我的摄像头中流处理帧，并在流媒体的同时保持闪光灯亮着？在windows上工作并在android上运行

相机0.8.1的例子并没有给我一个如何设置闪光模式状态的想法。但我仍然是一个新手，所以很可能会错过它。谢谢。Get this error══╡EXCEPTION BY WIDGETS LIBRARY╞═══════════════════════════════════════════════════════════The WIDGETS══╡EXCEPTION WIDGETS to the render tree:方法'setFlashMode‘在══╡上被调用。接收方:尝试的调用为空:setFlashMode(‘FlashMode’的实例)

当抛出异常时，这就是堆栈：#0核心补丁(dart: Object.noSuchMethod - (package:flutter/src/widgets/framework.dart:4632:57) /object_patch.dart:54:5) #1 Object.noSuchMethod(软件包：_CameraAppState.initState /main.dart:26:13) #2 StatefulElement._firstBuild Object.noSuchMethod #3 ComponentElement.mount _CameraAppState.initState #4 _CameraAppState.initState(软件包:StatefulElement._firstBuild/src/ComponentElement.mount Element.inflateWidgetRenderObjectToWidgetAdapter.attachToRenderTree. ( /framework.dart:3541:14) #5 Element.updateChild (package:flutter/src/widgets/framework.dart:3306:18) #6 RenderObjectToWidgetElement._rebuild (package:flutter/src/widgets/binding.dart:1182:16) #7 RenderObjectToWidgetElement._rebuild(package:flutter/src/widgets/binding.dart:1182:16) #8 RenderObjectToWidgetAdapter.attachToRenderTree.(package:flutter/src/widgets/binding.dart:1095:18) #9 BuildOwner.buildScope RenderObjectToWidgetAdapter.attachToRenderTree (package:flutter/src/widgets/binding.dart:1094:13) #10 (package:flutter/src/widgets/binding.dart:934:7) #11 BuildOwner.buildScope WidgetsBinding.attachRootWidget (package:flutter/src/widgets/binding.dart:934:7) #12 WidgetsBinding.scheduleAttachRootWidget。(package:flutter/src/widgets/binding.dart:915:7) (从_RawReceivePortImpl类、_Timer类、dart:async和dart:async-patch中省略了11帧)我有的代码是为了在这个时候进行预览，并希望在应用程序启动时启动flash。

    import 'dart:async';
    import 'dart:io';

    import 'package:flutter/material.dart';
    import 'package:camera/camera.dart';

    List<CameraDescription> cameras;

    Future<void> main() async {
      WidgetsFlutterBinding.ensureInitialized();

      cameras = await availableCameras();
         _cameraController.setFlashMode(FlashMode.always);

      runApp(CameraApp());
    }

    class CameraApp extends StatefulWidget {
      @override
      _CameraAppState createState() => _CameraAppState();
    }

    class _CameraAppState extends State<CameraApp> {
     CameraController controller;
 
      @override
      void initState() {

        super.initState();
        controller = CameraController(cameras[0],                         ResolutionPreset.max);

        controller.initialize().then((_) {

          if (!mounted) {
            return;
          }
          setState(() { 
    });

        });
      }

      @override
      void dispose() {
        controller?.dispose();
        super.dispose();
      }

      @override
      Widget build(BuildContext context) {
        if (!controller.value.isInitialized) {

          return Container();
        }
        return MaterialApp(
          home: CameraPreview(controller),
        );
      }
    }

Answer 1

您可以使用相机控制器设置flashmode，如下所示

CameraController  _cameraController;
List<CameraDescription> cameras=await availableCameras();
controller = CameraController(cameras[0], ResolutionPreset.max);
_cameraController.setFlashMode(FlashMode.always);
     _cameraController.setFlashMode(FlashMode.always);

并将控制器指定给相机预览

CameraPreview(_cameraController)

Answer 2

为了在流媒体的同时保持闪光灯的亮起，我唯一能做的就是使用controller.setFlashMode(FlashMode.torch)；