【发布时间】：2022-06-13 11:34:24
【问题描述】：
我尝试使用相机插件来执行连拍模式。但是每 0.2 秒拍照似乎是不可能的。因为 1 张图片几乎需要 1 秒
谁能指导一下如何在尽可能短的时间内有效地拍摄多张照片？
【问题讨论】：
标签： flutter
【发布时间】：2022-06-13 11:34:24
【问题描述】：
在 pubspc.yml 中添加这个
flutter_better_camera: ^1.0.2+1
例子：
import 'dart:async';
import 'dart:io';
import 'package:flutter_better_camera/camera.dart';
import 'package:flutter/material.dart';
import 'package:path_provider/path_provider.dart';
import 'package:video_player/video_player.dart';
class CameraExampleHome extends StatefulWidget {
@override
_CameraExampleHomeState createState() {
return _CameraExampleHomeState();
}
}
/// Returns a suitable camera icon for [direction].
IconData getCameraLensIcon(CameraLensDirection? direction) {
switch (direction) {
case CameraLensDirection.back:
return Icons.camera_rear;
case CameraLensDirection.front:
return Icons.camera_front;
case CameraLensDirection.external:
return Icons.camera;
}
throw ArgumentError('Unknown lens direction');
}
void logError(String code, String? message) =>
print('Error: $code\nError Message: $message');
class _CameraExampleHomeState extends State<CameraExampleHome>
with WidgetsBindingObserver {
CameraController? controller;
String? imagePath;
late String videoPath;
VideoPlayerController? videoController;
late VoidCallback videoPlayerListener;
bool enableAudio = true;
FlashMode flashMode = FlashMode.off;
@override
void initState() {
super.initState();
WidgetsBinding.instance!.addObserver(this);
}
@override
void dispose() {
WidgetsBinding.instance!.removeObserver(this);
super.dispose();
}
@override
void didChangeAppLifecycleState(AppLifecycleState state) {
// App state changed before we got the chance to initialize.
if (controller == null || !controller!.value.isInitialized!) {
return;
}
if (state == AppLifecycleState.inactive) {
controller?.dispose();
} else if (state == AppLifecycleState.resumed) {
if (controller != null) {
onNewCameraSelected(controller!.description);
}
}
}
final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();
@override
Widget build(BuildContext context) {
return Scaffold(
key: _scaffoldKey,
appBar: AppBar(
title: const Text('Camera example'),
),
body: Column(
children: <Widget>[
Expanded(
child: Container(
child: Padding(
padding: const EdgeInsets.all(1.0),
child: Center(
child: ZoomableWidget(
child: _cameraPreviewWidget(),
onTapUp: (scaledPoint) {
//controller.setPointOfInterest(scaledPoint);
},
onZoom: (zoom) {
print('zoom');
if (zoom < 11) {
controller!.zoom(zoom);
}
})),
),
decoration: BoxDecoration(
color: Colors.black,
border: Border.all(
color: controller != null && controller!.value.isRecordingVideo!
? Colors.redAccent
: Colors.grey,
width: 3.0,
),
),
),
),
_captureControlRowWidget(),
_toggleAudioWidget(),
Padding(
padding: const EdgeInsets.all(5.0),
child: Row(
mainAxisAlignment: MainAxisAlignment.start,
children: <Widget>[
_cameraTogglesRowWidget(),
_thumbnailWidget(),
],
),
),
],
),
);
}
/// Display the preview from the camera (or a message if the preview is not available).
Widget _cameraPreviewWidget() {
if (controller == null || !controller!.value.isInitialized!) {
return const Text(
'Tap a camera',
style: TextStyle(
color: Colors.white,
fontSize: 24.0,
fontWeight: FontWeight.w900,
),
);
} else {
return AspectRatio(
aspectRatio: controller!.value.aspectRatio,
child: CameraPreview(controller!),
);
}
}
/// Toggle recording audio
Widget _toggleAudioWidget() {
return Padding(
padding: const EdgeInsets.only(left: 25),
child: Row(
children: <Widget>[
const Text('Enable Audio:'),
Switch(
value: enableAudio,
onChanged: (bool value) {
enableAudio = value;
if (controller != null) {
onNewCameraSelected(controller!.description);
}
},
),
],
),
);
}
/// Display the thumbnail of the captured image or video.
Widget _thumbnailWidget() {
return Expanded(
child: Align(
alignment: Alignment.centerRight,
child: Row(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
videoController == null && imagePath == null
? Container()
: SizedBox(
child: (videoController == null)
? Image.file(File(imagePath!))
: Container(
child: Center(
child: AspectRatio(
aspectRatio:
videoController!.value.size != null
? videoController!.value.aspectRatio
: 1.0,
child: VideoPlayer(videoController!)),
),
decoration: BoxDecoration(
border: Border.all(color: Colors.pink)),
),
width: 64.0,
height: 64.0,
),
],
),
),
);
}
/// Display the control bar with buttons to take pictures and record videos.
Widget _captureControlRowWidget() {
return Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
mainAxisSize: MainAxisSize.max,
children: <Widget>[
IconButton(
icon: const Icon(Icons.camera_alt),
color: Colors.blue,
onPressed: controller != null &&
controller!.value.isInitialized! &&
!controller!.value.isRecordingVideo!
? onTakePictureButtonPressed
: null,
),
IconButton(
icon: const Icon(Icons.videocam),
color: Colors.blue,
onPressed: controller != null &&
controller!.value.isInitialized! &&
!controller!.value.isRecordingVideo!
? onVideoRecordButtonPressed
: null,
),
IconButton(
icon: controller != null && controller!.value.isRecordingPaused
? Icon(Icons.play_arrow)
: Icon(Icons.pause),
color: Colors.blue,
onPressed: controller != null &&
controller!.value.isInitialized! &&
controller!.value.isRecordingVideo!
? (controller != null && controller!.value.isRecordingPaused
? onResumeButtonPressed
: onPauseButtonPressed)
: null,
),
IconButton(
icon: controller != null && controller!.value.autoFocusEnabled!
? Icon(Icons.access_alarm)
: Icon(Icons.access_alarms),
color: Colors.blue,
onPressed: (controller != null && controller!.value.isInitialized!)
? toogleAutoFocus
: null,
),
_flashButton(),
IconButton(
icon: const Icon(Icons.stop),
color: Colors.red,
onPressed: controller != null &&
controller!.value.isInitialized! &&
controller!.value.isRecordingVideo!
? onStopButtonPressed
: null,
),
],
);
}
/// Flash Toggle Button
Widget _flashButton() {
IconData iconData = Icons.flash_off;
Color color = Colors.black;
if (flashMode == FlashMode.alwaysFlash) {
iconData = Icons.flash_on;
color = Colors.blue;
} else if (flashMode == FlashMode.autoFlash) {
iconData = Icons.flash_auto;
color = Colors.red;
}
return IconButton(
icon: Icon(iconData),
color: color,
onPressed: controller != null && controller!.value.isInitialized!
? _onFlashButtonPressed
: null,
);
}
/// Toggle Flash
Future<void> _onFlashButtonPressed() async {
bool hasFlash = false;
if (flashMode == FlashMode.off || flashMode == FlashMode.torch) {
// Turn on the flash for capture
flashMode = FlashMode.alwaysFlash;
} else if (flashMode == FlashMode.alwaysFlash) {
// Turn on the flash for capture if needed
flashMode = FlashMode.autoFlash;
} else {
// Turn off the flash
flashMode = FlashMode.off;
}
// Apply the new mode
await controller!.setFlashMode(flashMode);
// Change UI State
setState(() {});
}
/// Display a row of toggle to select the camera (or a message if no camera is available).
Widget _cameraTogglesRowWidget() {
final List<Widget> toggles = <Widget>[];
if (cameras.isEmpty) {
return const Text('No camera found');
} else {
for (CameraDescription cameraDescription in cameras) {
toggles.add(
SizedBox(
width: 90.0,
child: RadioListTile<CameraDescription>(
title: Icon(getCameraLensIcon(cameraDescription.lensDirection)),
groupValue: controller?.description,
value: cameraDescription,
onChanged: controller != null && controller!.value.isRecordingVideo!
? null
: onNewCameraSelected,
),
),
);
}
}
return Row(children: toggles);
}
String timestamp() => DateTime.now().millisecondsSinceEpoch.toString();
void showInSnackBar(String message) {
_scaffoldKey.currentState!.showSnackBar(SnackBar(content: Text(message)));
}
void onNewCameraSelected(CameraDescription? cameraDescription) async {
if (controller != null) {
await controller!.dispose();
}
controller = CameraController(
cameraDescription!,
ResolutionPreset.medium,
enableAudio: enableAudio,
);
// If the controller is updated then update the UI.
controller!.addListener(() {
if (mounted) setState(() {});
if (controller!.value.hasError) {
showInSnackBar('Camera error ${controller!.value.errorDescription}');
}
});
try {
await controller!.initialize();
} on CameraException catch (e) {
_showCameraException(e);
}
if (mounted) {
setState(() {});
}
}
void onTakePictureButtonPressed() {
takePicture().then((String? filePath) {
if (mounted) {
setState(() {
imagePath = filePath;
videoController?.dispose();
videoController = null;
});
if (filePath != null) showInSnackBar('Picture saved to $filePath');
}
});
}
void onVideoRecordButtonPressed() {
startVideoRecording().then((String? filePath) {
if (mounted) setState(() {});
if (filePath != null) showInSnackBar('Saving video to $filePath');
});
}
void onStopButtonPressed() {
stopVideoRecording().then((_) {
if (mounted) setState(() {});
showInSnackBar('Video recorded to: $videoPath');
});
}
void onPauseButtonPressed() {
pauseVideoRecording().then((_) {
if (mounted) setState(() {});
showInSnackBar('Video recording paused');
});
}
void onResumeButtonPressed() {
resumeVideoRecording().then((_) {
if (mounted) setState(() {});
showInSnackBar('Video recording resumed');
});
}
void toogleAutoFocus() {
controller!.setAutoFocus(!controller!.value.autoFocusEnabled!);
showInSnackBar('Toogle auto focus');
}
Future<String?> startVideoRecording() async {
if (!controller!.value.isInitialized!) {
showInSnackBar('Error: select a camera first.');
return null;
}
final Directory extDir = await getApplicationDocumentsDirectory();
final String dirPath = '${extDir.path}/Movies/flutter_test';
await Directory(dirPath).create(recursive: true);
final String filePath = '$dirPath/${timestamp()}.mp4';
if (controller!.value.isRecordingVideo!) {
// A recording is already started, do nothing.
return null;
}
try {
videoPath = filePath;
await controller!.startVideoRecording(filePath);
} on CameraException catch (e) {
_showCameraException(e);
return null;
}
return filePath;
}
Future<void> stopVideoRecording() async {
if (!controller!.value.isRecordingVideo!) {
return null;
}
try {
await controller!.stopVideoRecording();
} on CameraException catch (e) {
_showCameraException(e);
return null;
}
await _startVideoPlayer();
}
Future<void> pauseVideoRecording() async {
if (!controller!.value.isRecordingVideo!) {
return null;
}
try {
await controller!.pauseVideoRecording();
} on CameraException catch (e) {
_showCameraException(e);
rethrow;
}
}
Future<void> resumeVideoRecording() async {
if (!controller!.value.isRecordingVideo!) {
return null;
}
try {
await controller!.resumeVideoRecording();
} on CameraException catch (e) {
_showCameraException(e);
rethrow;
}
}
Future<void> _startVideoPlayer() async {
final VideoPlayerController vcontroller =
VideoPlayerController.file(File(videoPath));
videoPlayerListener = () {
if (videoController != null && videoController!.value.size != null) {
// Refreshing the state to update video player with the correct ratio.
if (mounted) setState(() {});
videoController!.removeListener(videoPlayerListener);
}
};
vcontroller.addListener(videoPlayerListener);
await vcontroller.setLooping(true);
await vcontroller.initialize();
await videoController?.dispose();
if (mounted) {
setState(() {
imagePath = null;
videoController = vcontroller;
});
}
await vcontroller.play();
}
Future<String?> takePicture() async {
if (!controller!.value.isInitialized!) {
showInSnackBar('Error: select a camera first.');
return null;
}
final Directory extDir = await getApplicationDocumentsDirectory();
final String dirPath = '${extDir.path}/Pictures/flutter_test';
await Directory(dirPath).create(recursive: true);
final String filePath = '$dirPath/${timestamp()}.jpg';
if (controller!.value.isTakingPicture!) {
// A capture is already pending, do nothing.
return null;
}
try {
await controller!.takePicture(filePath);
} on CameraException catch (e) {
_showCameraException(e);
return null;
}
return filePath;
}
void _showCameraException(CameraException e) {
logError(e.code, e.description);
showInSnackBar('Error: ${e.code}\n${e.description}');
}
}
class CameraApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return
MaterialApp(
theme: ThemeData(
accentTextTheme: TextTheme(body2: TextStyle(color: Colors.white)),
),
home: CameraExampleHome(),
);
}
}
List<CameraDescription> cameras = [];
Future<void> main() async {
// Fetch the available cameras before initializing the app.
try {
WidgetsFlutterBinding.ensureInitialized();
cameras = await availableCameras();
} on CameraException catch (e) {
logError(e.code, e.description);
}
runApp(CameraApp());
}
//Zoomer this will be a seprate widget
class ZoomableWidget extends StatefulWidget {
final Widget? child;
final Function? onZoom;
final Function? onTapUp;
const ZoomableWidget({Key? key, this.child, this.onZoom, this.onTapUp})
: super(key: key);
@override
_ZoomableWidgetState createState() => _ZoomableWidgetState();
}
class _ZoomableWidgetState extends State<ZoomableWidget> {
Matrix4 matrix = Matrix4.identity();
double zoom = 1;
double prevZoom = 1;
bool showZoom = false;
Timer? t1;
bool handleZoom(newZoom){
if (newZoom >= 1) {
if (newZoom > 10) {
return false;
}
setState(() {
showZoom = true;
zoom = newZoom;
});
if (t1 != null) {
t1!.cancel();
}
t1 = Timer(Duration(milliseconds: 2000), () {
setState(() {
showZoom = false;
});
});
}
widget.onZoom!(zoom);
return true;
}
@override
Widget build(BuildContext context) {
return GestureDetector(
onScaleStart: (scaleDetails) {
print('scalStart');
setState(() => prevZoom = zoom);
//print(scaleDetails);
},
onScaleUpdate: (ScaleUpdateDetails scaleDetails) {
var newZoom = (prevZoom * scaleDetails.scale);
handleZoom(newZoom);
},
onScaleEnd: (scaleDetails) {
print('end');
//print(scaleDetails);
},
onTapUp: (TapUpDetails det) {
final RenderBox box = context.findRenderObject() as RenderBox;
final Offset localPoint = box.globalToLocal(det.globalPosition);
final Offset scaledPoint =
localPoint.scale(1 / box.size.width, 1 / box.size.height);
// TODO IMPLIMENT
// widget.onTapUp(scaledPoint);
},
child: Stack(children: [
Column(
children: <Widget>[
Container(
child: Expanded(
child: widget.child!,
),
),
],
),
Visibility(
visible: showZoom, //Default is true,
child: Positioned.fill(
child: Container(
child: Column(
crossAxisAlignment: CrossAxisAlignment.center,
mainAxisSize: MainAxisSize.max,
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
Align(
alignment: Alignment.bottomCenter,
child:
SliderTheme(
data: SliderTheme.of(context).copyWith(
valueIndicatorTextStyle: TextStyle(
color: Colors.amber, letterSpacing: 2.0, fontSize: 30),
valueIndicatorColor: Colors.blue,
// This is what you are asking for
inactiveTrackColor: Color(0xFF8D8E98),
// Custom Gray Color
activeTrackColor: Colors.white,
thumbColor: Colors.red,
overlayColor: Color(0x29EB1555),
// Custom Thumb overlay Color
thumbShape:
RoundSliderThumbShape(enabledThumbRadius: 12.0),
overlayShape:
RoundSliderOverlayShape(overlayRadius: 20.0),
),
child: Slider(
value: zoom,
onChanged: (double newValue) {
handleZoom(newValue);
},
label: "$zoom",
min: 1,
max: 10,
),
),
),
],
)),
),
//maintainSize: bool. When true this is equivalent to invisible;
//replacement: Widget. Defaults to Sizedbox.shrink, 0x0
)
]));
}
}
更多请查看此链接： https://pub.flutter-io.cn/packages/flutter_better_camera
【讨论】：