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flutter开发实战-Camera自定义相机拍照功能实现 在项目中使用image_picker插件时候，在android设备上使用无法默认设置前置摄像头（暂时不清楚什么原因），由于项目默认需要使用前置摄像头，所以最终采用自定义相机实现拍照功能。 二、Camera使用前设置在工程的iOS的info.plist文件中添加相机、麦克风权限描述 NSCameraUsageDescription your usage description here NSMicrophoneUsageDescription your usage description here在工程的Android的gradle设置minSdkVersion 找到android/app/build.gradle文件 minSdkVersion 21 二、使用插件Camera插件camera : 适用于iOS、Android和Web的Flutter插件，允许访问设备摄像头。 我们需要在工程中引入camera插件 pubspec.yaml中引入插件 # Camera相机拍照等 camera: ^0.10.5+5处理相机访问权限 在初始化相机控制器时可能会引发权限错误，需要处理这些错误。 CameraAccessDenied：当用户拒绝相机访问权限时抛出。 CameraAccessDeniedWithoutPrompt：仅限iOS。当用户先前拒绝该权限时抛出。iOS不允许再次提示警报对话框。用户必须进入“设置”>“隐私”>“相机”才能访问相机。 CameraAccessRestricted:仅限iOS。当摄像头访问受到限制且用户无法授予权限（家长控制）时抛出。 AudioAccessDenied：当用户拒绝音频访问权限时抛出。 AudioAccessDeniedWithoutPrompt：目前仅限iOS。当用户先前拒绝该权限时抛出。iOS不允许再次提示警报对话框。用户必须转到“设置”>“隐私”>“麦克风”才能启用音频访问。 AudioAccessRestricted:目前仅限iOS。当音频访问受到限制并且用户无法授予权限（家长控制）时抛出。 2.1、camera功能设置当使用camera时，我们需要设置一些camera的属性内容，比如切换前后摄像头、开启拍照、开启预览、停止预览等。 获取cameras final cameras = await availableCameras();camera中使用CameraController来控制相关功能。 设置缩放级别zoomLevel Future setZoomLevel(double scale) async { await controller!.setZoomLevel(scale); }切换闪光灯模式 void onSetFlashModeButtonPressed(FlashMode mode) { setFlashMode(mode).then((_) { if (mounted) { setState(() {}); } showInSnackBar('Flash mode set to ${mode.toString().split('.').last}'); }); }设置曝光模式 void onSetExposureModeButtonPressed(ExposureMode mode) { setExposureMode(mode).then((_) { if (mounted) { setState(() {}); } showInSnackBar('Exposure mode set to ${mode.toString().split('.').last}'); }); }设置焦距模式 void onSetFocusModeButtonPressed(FocusMode mode) { setFocusMode(mode).then((_) { if (mounted) { setState(() {}); } showInSnackBar('Focus mode set to ${mode.toString().split('.').last}'); }); }开启预览 Future onResumePreview() async { final CameraController? cameraController = controller; if (cameraController == null || !cameraController.value.isInitialized) { print('Error: select a camera first.'); return; } if (cameraController.value.isPreviewPaused) { await cameraController.resumePreview(); } }暂停预览 Future onPausePreview() async { final CameraController? cameraController = controller; if (cameraController == null || !cameraController.value.isInitialized) { print('Error: select a camera first.'); return; } if (!cameraController.value.isPreviewPaused) { await cameraController.pausePreview(); } }切换前后摄像头 void onViewFinderTap(TapDownDetails details, BoxConstraints constraints) { if (controller == null) { return; } final CameraController? cameraController = controller; final Offset offset = Offset( details.localPosition.dx / constraints.maxWidth, details.localPosition.dy / constraints.maxHeight, ); cameraController?.setExposurePoint(offset); cameraController?.setFocusPoint(offset); } Future onNewCameraSelected(CameraDescription cameraDescription) async { final CameraController cameraController = CameraController( cameraDescription, ResolutionPreset.high, enableAudio: enableAudio, imageFormatGroup: ImageFormatGroup.jpeg, ); controller = cameraController; // If the controller is updated then update the UI. cameraController.addListener(() { if (mounted) { setState(() {}); } if (cameraController.value.hasError) { print("Camera error ${cameraController.value.errorDescription}"); } }); try { await cameraController.initialize(); await Future.wait([ // The exposure mode is currently not supported on the web. cameraController .getMaxZoomLevel() .then((double value) => _maxAvailableZoom = value), cameraController .getMinZoomLevel() .then((double value) => _minAvailableZoom = value), ]); } on CameraException catch (e) { // _showCameraException(e); } setState(() { isCameraStarting = true; }); controller!.initialize().then((_) { if (!mounted) { return; } setState(() { isCameraStarting = false; }); }).catchError((Object e) { if (e is CameraException) { switch (e.code) { case 'CameraAccessDenied': // Handle access errors here. break; default: // Handle other errors here. break; } } }); if (mounted) { setState(() {}); } }上面介绍了一些CameraController的常用设置，当然肯定不全，大致列了几条。 2.2、WidgetsBinding 生命周期改变相机设置我们自定义Camera，需要在didChangeAppLifecycleState来处理相机。我们需要添加mixin WidgetsBindingObserver 在initState中添加WidgetsBinding.instance?.addObserver(this); 在dispose中移除WidgetsBinding.instance?.removeObserver(this); 这样我们就可以在app的生命周期状态改变时候，更新相机 @override void didChangeAppLifecycleState(AppLifecycleState state) { final CameraController? cameraController = controller; // App state changed before we got the chance to initialize. if (cameraController == null || !cameraController.value.isInitialized) { return; } if (state == AppLifecycleState.inactive) { cameraController.dispose(); } else if (state == AppLifecycleState.resumed) { onNewCameraSelected(cameraController.description); } } 2.3、处理预览的画面出现变形的问题在处理自定义相机功能，我们需要处理预览的画面出现变形的问题。这里我们需要使用CameraPreview。 我们需要使用Transform.scale来进行处理，处理预览的画面出现变形的问题的解决代码如下 Widget buildCameraPreviewWidget(BuildContext context) { final Size size = MediaQuery.of(context).size; final CameraController? cameraController = controller; return Container( width: size.width, height: size.height, child: Stack( alignment: Alignment.center, clipBehavior: Clip.hardEdge, children: [ RepaintBoundary( key: _cameraViewGlobalKey, child: Transform.scale( scale: 1.0, // scale: controller!.value.aspectRatio / deviceRatio, alignment: Alignment.center, child: AspectRatio( aspectRatio: size.aspectRatio, child: OverflowBox( alignment: Alignment.center, child: FittedBox( fit: BoxFit.fitHeight, child: SizedBox( width: size.width, height: size.width * cameraController!.value.aspectRatio, child: Stack(fit: StackFit.expand, children: [ _cameraPreviewWidget(), ]), ), ), ), ), ), ), ], ), ); } /// Display the preview from the camera (or a message if the preview is not available). Widget _cameraPreviewWidget() { final CameraController? cameraController = controller; if (cameraController == null || !cameraController.value.isInitialized) { return const Text( 'cameraController未初始化完成', style: TextStyle( color: Colors.white, fontSize: 24.0, fontWeight: FontWeight.w900, ), ); } else { return Listener( onPointerDown: (_) => _pointers++, onPointerUp: (_) => _pointers--, child: CameraPreview( controller!, child: LayoutBuilder( builder: (BuildContext context, BoxConstraints constraints) { return GestureDetector( behavior: HitTestBehavior.opaque, onScaleStart: _handleScaleStart, onScaleUpdate: _handleScaleUpdate, onTapDown: (TapDownDetails details) => onViewFinderTap(details, constraints), ); }), ), ); } }在代码中，我们使用Transform.scale设置为1.0，当设置AspectRatio来设置size.aspectRatio。 2.4、实现拍照功能在我们代码中，我们使用takePicture来实现拍照，拍照代码如下 Future onTakePicture() async { setState(() { isTaking = true; }); takePicture().then((XFile? file) async { if (mounted) { onPausePreview(); if (file != null) { // 保存到相册 // await SaveToAlbumUtil.saveLocalImage(file.path); RenderBox renderBox = _cameraContainerGlobalKey.currentContext! .findRenderObject() as RenderBox; // offset.dx , offset.dy 就是控件的左上角坐标 Offset offset = renderBox.localToGlobal(Offset.zero); //获取size Size size = renderBox.size; // 创建文件path String imageDir = await PathUtil.createDirectory("local_images"); String imagePath = '$imageDir/${TimeUtil.currentTimeMillis()}.png'; // // 获取当前设备的像素比 double dpr = ui.window.devicePixelRatio; print("devicePixelRatio:${dpr}"); print( "offset:(${offset.dx},${offset.dy})--size:(${size.width},${size.height})"); File? targetFile = await ImageUtil.cropImage( file.path, imagePath, x: (dpr * offset.dx).floor(), y: (dpr * offset.dy).floor(), width: (dpr * size.width).ceil(), height: (dpr * size.height).ceil(), flipHorizontal: isCameraFront, ); print("cropImage targetFile:${targetFile}"); if (targetFile != null) { selectedImagePath = targetFile.path; // await SaveToAlbumUtil.saveLocalImage(targetFile.path); } setState(() { isHasTakePhoto = true; }); } else { // 没有获得图片，重试 } setState(() { isTaking = false; }); } }); }在裁剪图片中实现如下 import 'dart:io'; import 'dart:math'; import 'dart:ui' as ui; import 'dart:math' as math; import 'package:flutter/cupertino.dart'; import 'package:flutter/foundation.dart'; import 'package:flutter/rendering.dart'; import 'package:image/image.dart' as IMG; class ImageUtil { //拿到图片的字节数组 static Future loadImageByFile(String path) async { var list = await File(path).readAsBytes(); return ImageUtil.loadImageByUInt8List(list); } //通过[Uint8List]获取图片 static Future loadImageByUInt8List(Uint8List list) async { ui.Codec codec = await ui.instantiateImageCodec(list); ui.FrameInfo frame = await codec.getNextFrame(); return frame.image; } // 根据GlobalKey来截图Widget static Future makeImageUInt8List(GlobalKey globalKey) async { RenderRepaintBoundary boundary = globalKey.currentContext?.findRenderObject() as RenderRepaintBoundary; // 这个可以获取当前设备的像素比 var dpr = ui.window.devicePixelRatio; ui.Image image = await boundary.toImage(pixelRatio: dpr); ByteData? byteData = await image.toByteData(format: ui.ImageByteFormat.png); Uint8List? pngBytes = byteData?.buffer.asUint8List(); return pngBytes; } static Future cropSquare( String srcFilePath, String destFilePath, bool flip) async { var bytes = await File(srcFilePath).readAsBytes(); IMG.Image? src = IMG.decodeImage(bytes); if (src != null) { var cropSize = min(src.width, src.height); int offsetX = (src.width - min(src.width, src.height)) ~/ 2; int offsetY = (src.height - min(src.width, src.height)) ~/ 2; // IMG.Image destImage = IMG.copyCrop(src, offsetX, offsetY, cropSize, cropSize); IMG.Image destImage = IMG.copyCrop(src, x: offsetX, y: offsetY, width: cropSize, height: cropSize); if (flip) { destImage = IMG.flipVertical(destImage); } var jpg = IMG.encodeJpg(destImage); return await File(destFilePath).writeAsBytes(jpg); } else { throw StateError("cropSquare error"); } } static Future cropImage( String srcFilePath, String destFilePath, { required int x, required int y, required int width, required int height, bool flipVertical = false, bool flipHorizontal = false, }) async { var bytes = await File(srcFilePath).readAsBytes(); IMG.Image? src = IMG.decodeImage(bytes); if (src != null) { print("cropImage scr size:(${src.width},${src.height})"); IMG.Image destImage = IMG.copyCrop(src, x: x, y: y, width: width, height: height); if (flipVertical) { destImage = IMG.flipVertical(destImage); } if (flipHorizontal) { destImage = IMG.flipHorizontal(destImage); } var jpg = IMG.encodeJpg(destImage); return await File(destFilePath).writeAsBytes(jpg); } else { throw StateError("cropSquare error"); } } } 2.5、拍照完重拍逻辑当拍照后可能需要重新拍照，这时候我们需要重拍逻辑。 void onRetakeButtonPressed() { setState(() { isHasTakePhoto = false; }); selectedImagePath = null; onResumePreview(); } Future onResumePreview() async { final CameraController? cameraController = controller; if (cameraController == null || !cameraController.value.isInitialized) { print('Error: select a camera first.'); return; } if (cameraController.value.isPreviewPaused) { await cameraController.resumePreview(); } } 三、实现自定义相机拍照的功能完整代码我们实现了实现自定义相机拍照的功能完整代码如下 // Copyright 2013 The Flutter Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. // ignore_for_file: public_member_api_docs import 'dart:async'; import 'dart:io'; import 'package:camera/camera.dart'; import 'package:flutter/foundation.dart'; import 'package:flutter/material.dart'; import 'package:flutter_app_demolab/image_util.dart'; import 'package:flutter_app_demolab/path_util.dart'; import 'dart:ui' as ui; import 'package:flutter_app_demolab/tools/utils/color_util.dart'; import 'package:flutter_app_demolab/tools/utils/time_util.dart'; import 'package:flutter_screenutil/flutter_screenutil.dart'; class MyCameraPage extends StatefulWidget { const MyCameraPage({ super.key, required this.cameras, required this.onSelectedImagePathPressed, }); final List cameras; final Function(String? selectedImagePath) onSelectedImagePathPressed; @override State createState() => _MyCameraPageState(); } class _MyCameraPageState extends State with WidgetsBindingObserver, TickerProviderStateMixin { CameraController? controller; GlobalKey _cameraViewGlobalKey = GlobalKey(); GlobalKey _cameraContainerGlobalKey = GlobalKey(); bool enableAudio = false; // Counting pointers (number of user fingers on screen) ///以下是关于手指缩放画面的变量 int _pointers = 0; double _minAvailableZoom = 1.0; double _maxAvailableZoom = 1.0; double _currentScale = 1.0; double _baseScale = 1.0; Size? mediaSize; double? scale; double? defaultZoomLevel; bool isHasTakePhoto = false; bool isCameraFront = true; String? selectedImagePath; bool isTaking = false; bool isCameraStarting = false; @override void initState() { super.initState(); // To display the current output from the Camera, // create a CameraController. if (widget.cameras.isNotEmpty && widget.cameras.length >= 2) { controller = CameraController( // Get a specific camera from the list of available cameras. widget.cameras[1], // Define the resolution to use. ResolutionPreset.high, ); // Next, initialize the controller. This returns a Future. setState(() { isCameraStarting = true; }); controller!.initialize().then((_) { if (!mounted) { return; } setState(() { isCameraStarting = false; }); }).catchError((Object e) { if (e is CameraException) { switch (e.code) { case 'CameraAccessDenied': // Handle access errors here. break; default: // Handle other errors here. break; } } }); } WidgetsBinding.instance?.addObserver(this); } @override void dispose() { WidgetsBinding.instance?.removeObserver(this); controller?.dispose(); super.dispose(); } @override void didChangeAppLifecycleState(AppLifecycleState state) { final CameraController? cameraController = controller; // App state changed before we got the chance to initialize. if (cameraController == null || !cameraController.value.isInitialized) { return; } if (state == AppLifecycleState.inactive) { cameraController.dispose(); } else if (state == AppLifecycleState.resumed) { onNewCameraSelected(cameraController.description); } } final GlobalKey _scaffoldKey = GlobalKey(); @override Widget build(BuildContext context) { return Scaffold( key: _scaffoldKey, body: buildCameraContainer(context), ); } Widget buildCameraContainer(BuildContext context) { final Size size = MediaQuery.of(context).size; if (widget.cameras.isEmpty) { return Container( width: size.width, height: size.height, decoration: const BoxDecoration( color: Colors.black, ), child: Text( "未获取到可用的相机，请退出重试。", textAlign: TextAlign.center, maxLines: 2, overflow: TextOverflow.ellipsis, softWrap: true, style: TextStyle( fontSize: 16, fontWeight: FontWeight.w500, fontStyle: FontStyle.normal, color: ColorUtil.hexColor(0xffffff), decoration: TextDecoration.none, ), ), ); } else { return Container( key: _cameraContainerGlobalKey, width: size.width, height: size.height, decoration: const BoxDecoration( color: Colors.black, ), child: Stack( alignment: Alignment.center, children: [ Column( children: [ Expanded( child: buildFutureBuilder(context), ) ], ), buildStackBarWidget(context), ], ), ); } } Widget buildFutureBuilder(BuildContext context) { if (controller != null && controller!.value.isInitialized) { ///初始化完成以后，再获取可以缩放画面最大最小的参数 mediaSize = MediaQuery.of(context).size; scale = 1 / (controller!.value.aspectRatio * mediaSize!.aspectRatio); controller! .getMaxZoomLevel() .then((double value) => _maxAvailableZoom = value); controller! .getMinZoomLevel() .then((double value) => _minAvailableZoom = value); return buildCameraPreviewWidget(context); } return const Center(child: CircularProgressIndicator()); } Widget buildStackBarWidget(BuildContext context) { final Size size = MediaQuery.of(context).size; double bottomBarHeight = 120; double cameraHeight = size.height - bottomBarHeight; EdgeInsets viewPadding = MediaQuery.of(context).viewPadding; return Container( child: Stack( children: [ Positioned( bottom: 0, child: Container( width: size.width, height: bottomBarHeight, color: Colors.transparent, child: Stack( alignment: Alignment.center, children: [ Positioned( left: 25, child: buildCloseIcon(context), ), buildTakePhotoButton(context), Positioned( right: 25, child: buildRetakeButton(context), ), ], ), ), ), Positioned( top: viewPadding.top + 25, right: 10, child: buildExchangeButton(context), ), ], ), ); } Widget buildCameraPreviewWidget(BuildContext context) { final Size size = MediaQuery.of(context).size; final CameraController? cameraController = controller; return Container( width: size.width, height: size.height, child: Stack( alignment: Alignment.center, clipBehavior: Clip.hardEdge, children: [ RepaintBoundary( key: _cameraViewGlobalKey, child: Transform.scale( scale: 1.0, // scale: controller!.value.aspectRatio / deviceRatio, alignment: Alignment.center, child: AspectRatio( aspectRatio: size.aspectRatio, child: OverflowBox( alignment: Alignment.center, child: FittedBox( fit: BoxFit.fitHeight, child: SizedBox( width: size.width, height: size.width * cameraController!.value.aspectRatio, child: Stack(fit: StackFit.expand, children: [ _cameraPreviewWidget(), ]), ), ), ), ), ), ), ], ), ); } /// Display the preview from the camera (or a message if the preview is not available). Widget _cameraPreviewWidget() { final CameraController? cameraController = controller; if (cameraController == null || !cameraController.value.isInitialized) { return const Text( 'cameraController未初始化完成', style: TextStyle( color: Colors.white, fontSize: 24.0, fontWeight: FontWeight.w900, ), ); } else { return Listener( onPointerDown: (_) => _pointers++, onPointerUp: (_) => _pointers--, child: CameraPreview( controller!, child: LayoutBuilder( builder: (BuildContext context, BoxConstraints constraints) { return GestureDetector( behavior: HitTestBehavior.opaque, onScaleStart: _handleScaleStart, onScaleUpdate: _handleScaleUpdate, onTapDown: (TapDownDetails details) => onViewFinderTap(details, constraints), ); }), ), ); } } Widget buildCloseIcon(BuildContext context) { return GestureDetector( onTap: () { Navigator.pop(context); }, child: Container( color: Colors.transparent, child: Container( width: 50, height: 50, decoration: BoxDecoration( color: Colors.transparent, border: Border.all( color: Colors.transparent, style: BorderStyle.solid, width: 1, ), borderRadius: BorderRadius.all(Radius.circular(20)), ), child: Icon( Icons.close, size: 30, color: Colors.white, weight: 0.5, ), ), ), ); } Widget buildTakePhotoButton(BuildContext context) { return GestureDetector( onTap: () { if (isTaking == false) { if (isHasTakePhoto == true) { widget.onSelectedImagePathPressed(selectedImagePath); Navigator.pop(context); } else { onTakePicturePressed(); } } }, child: Container( color: Colors.transparent, child: Container( width: 60, height: 60, decoration: const BoxDecoration( color: Colors.transparent, ), child: Stack( alignment: Alignment.center, children: [ Image.asset( "assets/camera/my_take_photo.png", width: 60.0, height: 60.0, fit: BoxFit.contain, ), buildHasCheck(context), ], ), ), ), ); } Widget buildHasCheck(BuildContext context) { if (isTaking == true) { return buildLoading(context); } if (isHasTakePhoto) { return Icon( Icons.check, size: 30, color: Colors.black, weight: 0.5, ); } return Container(); } Widget buildExchangeButton(BuildContext context) { if (isHasTakePhoto == true) { return Container(); } return GestureDetector( onTap: () { onExchangeCameraPressed(); }, child: Container( color: Colors.transparent, child: Container( width: 50, height: 50, decoration: BoxDecoration( color: Colors.transparent, border: Border.all( color: Colors.transparent, style: BorderStyle.solid, width: 2, ), borderRadius: BorderRadius.all(Radius.circular(20)), ), child: Container( width: 40, height: 40, decoration: BoxDecoration( color: Colors.transparent, border: Border.all( color: Colors.transparent, style: BorderStyle.solid, width: 5, ), borderRadius: BorderRadius.all(Radius.circular(20)), ), child: Image.asset( "assets/camera/my_exchange_camera.png", width: 50.0, height: 50.0, fit: BoxFit.contain, ), ), ), ), ); } Widget buildRetakeButton(BuildContext context) { if (isHasTakePhoto == false) { return Container(); } return GestureDetector( onTap: () { onRetakeButtonPressed(); }, child: Container( color: Colors.transparent, child: Container( width: 70, height: 38, alignment: Alignment.center, decoration: BoxDecoration( color: ColorUtil.hexColor(0x000000, alpha: 0.25), border: Border.all( color: Colors.transparent, style: BorderStyle.solid, width: 2, ), borderRadius: BorderRadius.all(Radius.circular(5)), ), child: Text( "重拍", textAlign: TextAlign.center, maxLines: 2, overflow: TextOverflow.ellipsis, softWrap: true, style: TextStyle( fontSize: 16, fontWeight: FontWeight.w500, fontStyle: FontStyle.normal, color: ColorUtil.hexColor(0xffffff), decoration: TextDecoration.none, ), ), ), ), ); } Widget buildLoading(BuildContext context) { return SizedBox( height: 58, width: 58, child: CircularProgressIndicator( backgroundColor: Colors.grey[200], valueColor: AlwaysStoppedAnimation(Colors.blue), ), ); } void onRetakeButtonPressed() { setState(() { isHasTakePhoto = false; }); selectedImagePath = null; onResumePreview(); } Future onPausePreview() async { final CameraController? cameraController = controller; if (cameraController == null || !cameraController.value.isInitialized) { print('Error: select a camera first.'); return; } if (!cameraController.value.isPreviewPaused) { await cameraController.pausePreview(); } } Future onResumePreview() async { final CameraController? cameraController = controller; if (cameraController == null || !cameraController.value.isInitialized) { print('Error: select a camera first.'); return; } if (cameraController.value.isPreviewPaused) { await cameraController.resumePreview(); } } Future onExchangeCameraPressed() async { setState(() { isHasTakePhoto = false; }); if (isCameraFront == true) { if (widget.cameras.isNotEmpty && widget.cameras.length >= 2) { onNewCameraSelected(widget.cameras[0]); } isCameraFront = false; } else { if (widget.cameras.isNotEmpty && widget.cameras.length >= 2) { onNewCameraSelected(widget.cameras[1]); } isCameraFront = true; } } void onTakePicturePressed() { onTakePicture(); } Future onTakePicture() async { setState(() { isTaking = true; }); takePicture().then((XFile? file) async { if (mounted) { onPausePreview(); if (file != null) { // 保存到相册 // await SaveToAlbumUtil.saveLocalImage(file.path); RenderBox renderBox = _cameraContainerGlobalKey.currentContext! .findRenderObject() as RenderBox; // offset.dx , offset.dy 就是控件的左上角坐标 Offset offset = renderBox.localToGlobal(Offset.zero); //获取size Size size = renderBox.size; // 创建文件path String imageDir = await PathUtil.createDirectory("local_images"); String imagePath = '$imageDir/${TimeUtil.currentTimeMillis()}.png'; // // 获取当前设备的像素比 double dpr = ui.window.devicePixelRatio; print("devicePixelRatio:${dpr}"); print( "offset:(${offset.dx},${offset.dy})--size:(${size.width},${size.height})"); File? targetFile = await ImageUtil.cropImage( file.path, imagePath, x: (dpr * offset.dx).floor(), y: (dpr * offset.dy).floor(), width: (dpr * size.width).ceil(), height: (dpr * size.height).ceil(), flipHorizontal: isCameraFront, ); print("cropImage targetFile:${targetFile}"); if (targetFile != null) { selectedImagePath = targetFile.path; // await SaveToAlbumUtil.saveLocalImage(targetFile.path); } setState(() { isHasTakePhoto = true; }); } else { // 没有获得图片，重试 } setState(() { isTaking = false; }); } }); } Future _handleScaleStart(ScaleStartDetails details) async { _baseScale = _currentScale; await controller!.setZoomLevel(_minAvailableZoom); } Future _handleScaleUpdate(ScaleUpdateDetails details) async { // When there are not exactly two fingers on screen don't scale if (controller == null || _pointers != 2) { return; } _currentScale = (_baseScale * details.scale) .clamp(_minAvailableZoom, _maxAvailableZoom); await controller!.setZoomLevel(_currentScale); } void onViewFinderTap(TapDownDetails details, BoxConstraints constraints) { if (controller == null) { return; } final CameraController? cameraController = controller; final Offset offset = Offset( details.localPosition.dx / constraints.maxWidth, details.localPosition.dy / constraints.maxHeight, ); cameraController?.setExposurePoint(offset); cameraController?.setFocusPoint(offset); } Future onNewCameraSelected(CameraDescription cameraDescription) async { final CameraController cameraController = CameraController( cameraDescription, ResolutionPreset.high, enableAudio: enableAudio, imageFormatGroup: ImageFormatGroup.jpeg, ); controller = cameraController; // If the controller is updated then update the UI. cameraController.addListener(() { if (mounted) { setState(() {}); } if (cameraController.value.hasError) { print("Camera error ${cameraController.value.errorDescription}"); } }); try { await cameraController.initialize(); await Future.wait([ // The exposure mode is currently not supported on the web. cameraController .getMaxZoomLevel() .then((double value) => _maxAvailableZoom = value), cameraController .getMinZoomLevel() .then((double value) => _minAvailableZoom = value), ]); } on CameraException catch (e) { // _showCameraException(e); } setState(() { isCameraStarting = true; }); controller!.initialize().then((_) { if (!mounted) { return; } setState(() { isCameraStarting = false; }); }).catchError((Object e) { if (e is CameraException) { switch (e.code) { case 'CameraAccessDenied': // Handle access errors here. break; default: // Handle other errors here. break; } } }); if (mounted) { setState(() {}); } } Future takePicture() async { final CameraController? cameraController = controller; if (cameraController == null || !cameraController.value.isInitialized) { print("Error: select a camera first."); return null; } if (cameraController.value.isTakingPicture) { // A capture is already pending, do nothing. return null; } try { final XFile file = await cameraController.takePicture(); return file; } on CameraException catch (e) { print("takePicture CameraException e:${e.toString()}"); return null; } } }当需要拍照时候，我们调用showModalBottomSheet来打开camera //显示底部弹窗 static void bottomSheetDialog(BuildContext context, Widget widget) { showModalBottomSheet( context: context, isScrollControlled: true, builder: (ctx) { return widget; }, ); } //返回上一级 static void pop(BuildContext context) { Navigator.pop(context); }打开自定义相机页面 Future testCustomCamera(BuildContext context) async { final cameras = await availableCameras(); DialogUtils.bottomSheetDialog( context, MyCameraPage( cameras: cameras, onSelectedImagePathPressed: (String? selectedImagePath) { print("selectedImageFilePath:${selectedImagePath}"); if (selectedImagePath != null) { // File imageFile = File(selectedImagePath!); // if (callback != null) { // callback(imageFile); // } } }, ), ); }https://brucegwo.blog.csdn.net/article/details/135997096 四、小结flutter开发实战-Camera自定义相机拍照功能实现 学习记录，每天不停进步。 |
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