如何在颤振中打开相机闪光灯?

Question

我正在构建一个应用程序，您可以在其中将他们的视频上传到Firebase。我正在使用相机模块的相机包。我想在用户单击闪光灯图标或将其关闭时打开闪光灯。

我试图找到一种通过相机包打开闪光灯的方法，但我找不到任何打开闪光灯的方法。然后，我尝试使用灯包，但由于某种原因闪光灯没有打开。

import 'dart:io';
import 'package:firebase_storage/firebase_storage.dart';
import 'package:flutter/material.dart';
import 'package:camera/camera.dart';
import 'package:flutter_icons/flutter_icons.dart';
import 'package:fluttertoast/fluttertoast.dart';
import 'package:path/path.dart';
import 'package:path_provider/path_provider.dart';
import 'package:flutter/foundation.dart';
import 'package:lamp/lamp.dart';
enum FlashState { Flash_OFF, Flash_On, Flash_Auto }
class CameraView extends StatefulWidget {
final List<CameraDescription> cameras = [];
CameraView() {
availableCameras().then((cams) {
cameras.addAll(cams);
print(cameras.length);
print(cams.toString());
});
}
@override
_CameraViewState createState() => _CameraViewState();
}
class _CameraViewState extends State<CameraView>
with SingleTickerProviderStateMixin {
CameraController _controller;
int _selectedCameraIndex;
bool _isRecording;
FlashState currentFlashState = FlashState.Flash_OFF;
String flashIcon = 'flash-off';
AnimationController _animationController;
Animation _colorTween;
@override
void initState() {
_animationController =
AnimationController(vsync: this, duration: Duration(milliseconds: 300));
_colorTween = ColorTween(begin: Colors.blueGrey, end: Colors.red)
.animate(_animationController);
// _controller = CameraController(widget.cameras[0], ResolutionPreset.high,
//     enableAudio: true);
// _isRecording = false;
// _controller.initialize().then((_) {
//   if (!mounted) {
//     return;
//   }
//   setState(() {});
// });
if (widget.cameras.length > 0) {
setState(() {
_selectedCameraIndex = 0;
});
_switchCamera(widget.cameras[_selectedCameraIndex]);
}
super.initState();
}
@override
void dispose() {
_controller?.dispose();
super.dispose();
}
Future<void> _startVideoRecording(BuildContext context) async {
if (!_controller.value.isInitialized) {
await showDialog(
context: context,
builder: (BuildContext context) {
return AlertDialog(
title: Text('Camera Not Responding.'),
content: Center(
child: Text('Something went wrong.Try Again Later.'),
),
actions: <Widget>[
FlatButton(
child: Text('Okay.'),
onPressed: () {
Navigator.of(context).pop();
},
)
],
);
});
return null;
}
if (_controller.value.isRecordingVideo) {
return null;
}
setState(() {
_isRecording = true;
});
final Directory appDirectory = await getApplicationDocumentsDirectory();
final String videoDirectory = '${appDirectory.path}/Videos';
await Directory(videoDirectory).create(recursive: true);
final String currentTime = DateTime.now().millisecondsSinceEpoch.toString();
final String filePath = '$videoDirectory/$currentTime.mp4';
try {
//Lamp.turnOn();
await _controller.startVideoRecording(filePath);
//Lamp.turnOff();
StorageReference firebaseStorageReference =
FirebaseStorage.instance.ref().child(basename(filePath));
StorageUploadTask videoUploadTask = firebaseStorageReference.putFile(
File(filePath),
StorageMetadata(contentType: 'video/mp4'),
);
StorageTaskSnapshot uploadSnapshot = await videoUploadTask.onComplete;
} catch (error) {
print(error);
return null;
}
}
Future<void> _stopVideoRecording() async {
if (!_controller.value.isRecordingVideo) {
return null;
}
try {
await _controller.stopVideoRecording();
setState(() {
_isRecording = false;
});
} catch (error) {
print(error);
return null;
}
}
Future<void> _switchCamera(CameraDescription cameraDescription) async {
if (_controller != null) {
await _controller.dispose();
}
_controller = CameraController(cameraDescription, ResolutionPreset.high);
_controller.addListener(() {
if (mounted) {
setState(() {});
}
if (_controller.value.hasError) {
Fluttertoast.showToast(
msg: 'An Error Occured',
toastLength: Toast.LENGTH_SHORT,
gravity: ToastGravity.BOTTOM,
timeInSecForIos: 2,
textColor: Colors.white,
backgroundColor: Colors.black38);
}
});
try {
await _controller.initialize();
} catch (error) {
print(error);
}
if (mounted) {
setState(() {});
}
}
void _onSwitchCamera() {
_selectedCameraIndex = _selectedCameraIndex < widget.cameras.length - 1
? _selectedCameraIndex + 1
: 0;
CameraDescription selectedCamera = widget.cameras[_selectedCameraIndex];
_switchCamera(selectedCamera);
setState(() {
_selectedCameraIndex = _selectedCameraIndex;
});
}
@override
Widget build(BuildContext context) {
return _controller.value.isInitialized
? Stack(
fit: StackFit.expand,
children: <Widget>[
AspectRatio(
aspectRatio: _controller.value.aspectRatio,
child: CameraPreview(_controller),
),
Positioned(
left: MediaQuery.of(context).size.width * 0.40,
bottom: MediaQuery.of(context).size.height * 0.04,
child: AnimatedBuilder(
animation: _colorTween,
builder: (context, child) => IconButton(
icon: Icon(
MaterialCommunityIcons.getIconData('video'),
),
color: _colorTween.value,
iconSize: 80.0,
onPressed: () {
if (!_isRecording) {
_animationController.forward();
_startVideoRecording(context);
} else if (_isRecording) {
_animationController.reverse();
_stopVideoRecording();
}
},
),
),
),
Positioned(
right: 22.0,
top: 22.0,
child: IconButton(
icon: Icon(
MaterialCommunityIcons.getIconData('camera-switch'),
),
onPressed: _onSwitchCamera,
iconSize: 28.0,
),
),
Positioned(
left: 22.0,
top: 22.0,
child: IconButton(
icon: Icon(
MaterialCommunityIcons.getIconData(flashIcon),
),
onPressed: () {
currentFlashState =
currentFlashState.index < FlashState.values.length - 1
? FlashState.values[currentFlashState.index + 1]
: FlashState.values[0];
if(currentFlashState == FlashState.Flash_On){
setState(() {
flashIcon = 'flash';
});
//Lamp.turnOn(); Turning on the flash through lamp package flutter but the flash not opening 
} else if(currentFlashState == FlashState.Flash_Auto){
setState(() {
flashIcon = 'flash-auto';
});
} else {
setState(() {
flashIcon = 'flash-off';
});
//Lamp.turnOff(); 
}
},
),
)
],
)
: Container(
child: Center(
child: Text('Loading'),
),
);
}
}

Answer 1

根据相机的最新更新：^0.8.0。 您可以手动使用相机闪光灯：

步骤1： 首先按照整个相机说明进行操作： https://flutter.dev/docs/cookbook/plugins/picture-using-camera

步骤2： 然后创建任何按钮，并在其onPressing函数上，只需写下这一行。

//**For Flash OFF**:
ElevatedButton(
onPressed: () {
_cameraController.setFlashMode(FlashMode.off);
},
style: ElevatedButton.styleFrom(primary: Colors.transparent),
child: Text(
"Flash Off",
style: TextStyle(
color: Colors.white, backgroundColor: Colors.transparent),
),
),

// **For Flash ON**
ElevatedButton(
onPressed: () {
_cameraController.setFlashMode(FlashMode.always);
},
style: ElevatedButton.styleFrom(primary: Colors.transparent),
child: Text(
"Flash On",
style: TextStyle(
color: Colors.white, backgroundColor: Colors.transparent),
),
)
//**For AUTO Flash:**
ElevatedButton(
onPressed: () {
_cameraController.setFlashMode(FlashMode.auto);
},
style: ElevatedButton.styleFrom(primary: Colors.transparent),
child: Text(
"Auto Flash",
style: TextStyle(
color: Colors.white, backgroundColor: Colors.transparent),
),
)

Answer 2

目前还没有相机插件接受使用闪光灯。人们正在使用的一种解决方法是使用此软件包 https://pub.dev/packages/lamp 在拍照前打开手机灯，然后关闭。

这不是理想的解决方案，但现在是最好的解决方案

Answer 3

Asim Zubairs 的答案是正确的，对于颤振相机插件，最好强调FlashMode.always仅在拍摄照片时打开手电筒，但如果您想打开手电筒并保留它，对于视频录制等情况，FlashMode.torch将为此工作。

这是来自相机插件的闪光模式枚举

enum FlashMode {
/// Do not use the flash when taking a picture.
off,
/// Let the device decide whether to flash the camera when taking a picture.
auto,
/// Always use the flash when taking a picture.
always,
/// Turns on the flash light and keeps it on until switched off.
torch,
}

Answer 4

我尝试camera:^0.10.5+2并尝试在这里实施建议，但没有奏效。经过一段时间的研究，我找到了一种使用FlashMode.torch打开手电筒的方法。

像这样：_cameraController.setFlashMode(FlashMode.torch);

注： 我使用POCO电话。