Flutter人脸检测插件face_detector的使用

Flutter人脸检测插件face_detector的使用

在本教程中，我们将展示如何在Flutter应用中使用人脸检测插件。我们将通过一个简单的示例来演示如何使用摄像头捕获图像，并利用人脸检测功能来识别图像中的人脸。

1. 准备工作

首先，确保你已经安装了Flutter和Dart SDK。此外，你需要在你的项目中添加以下依赖项：

dependencies:
  flutter:
    sdk: flutter
  camera: ^0.9.4+5
  google_ml_kit: ^0.7.0

2. 创建主应用文件

我们将创建一个简单的Flutter应用，该应用允许用户选择不同的视觉任务，例如人脸检测。

示例代码

import 'dart:io';

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

// 获取可用的摄像头列表
List<CameraDescription> cameras = [];

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

  // 初始化摄像头
  cameras = await availableCameras();
  runApp(MyApp());
}

// 主应用类
class MyApp extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Home(),
    );
  }
}

// 主页面
class Home extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Google ML Kit Demo App'),
        centerTitle: true,
        elevation: 0,
      ),
      body: SafeArea(
        child: Center(
          child: SingleChildScrollView(
            child: Padding(
              padding: EdgeInsets.symmetric(horizontal: 16),
              child: Column(
                children: [
                  ExpansionTile(
                    title: const Text("Vision"),
                    children: [
                      CustomCard(
                        'Face Detector',
                        FaceDetectorView(),
                        featureCompleted: true,
                      ),
                    ],
                  ),
                  SizedBox(
                    height: 20,
                  ),
                ],
              ),
            ),
          ),
        ),
      ),
    );
  }
}

// 自定义卡片组件
class CustomCard extends StatelessWidget {
  final String _label;
  final Widget _viewPage;
  final bool featureCompleted;

  const CustomCard(this._label, this._viewPage,
      {this.featureCompleted = false});

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Card(
      elevation: 5,
      margin: EdgeInsets.only(bottom: 10),
      child: ListTile(
        tileColor: Theme.of(context).primaryColor,
        title: Text(
          _label,
          style: TextStyle(color: Colors.white, fontWeight: FontWeight.bold),
        ),
        onTap: () {
          if (Platform.isIOS && !featureCompleted) {
            ScaffoldMessenger.of(context).showSnackBar(SnackBar(
                content: const Text(
                    'This feature has not been implemented for iOS yet')));
          } else
            Navigator.push(
                context, MaterialPageRoute(builder: (context) => _viewPage));
        },
      ),
    );
  }
}

3. 使用人脸检测视图

为了实现人脸检测功能，我们需要创建一个FaceDetectorView类。这个类将负责初始化相机并处理检测到的人脸。

示例代码

// VisionDetectorViews/detector_views.dart
import 'dart:io';

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

class FaceDetectorView extends StatefulWidget {
  [@override](/user/override)
  _FaceDetectorViewState createState() => _FaceDetectorViewState();
}

class _FaceDetectorViewState extends State<FaceDetectorView> {
  CameraController? controller;
  FaceDetector? faceDetector;

  [@override](/user/override)
  void initState() {
    super.initState();
    initializeCamera();
  }

  Future<void> initializeCamera() async {
    final camera = cameras.first;
    controller = CameraController(
      camera,
      ResolutionPreset.high,
    );

    await controller!.initialize().then((_) async {
      if (!mounted) {
        return;
      }
      setState(() {});
    });

    faceDetector = GoogleMlKit.vision.faceDetector(
      FaceDetectorOptions(
        enableClassification: true,
        enableLandmarks: true,
        enableContours: true,
        enableTracking: true,
      ),
    );
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    if (!controller!.value.isInitialized) {
      return Container();
    }

    return AspectRatio(
      aspectRatio: controller!.value.aspectRatio,
      child: CameraPreview(controller!),
    );
  }

  [@override](/user/override)
  void dispose() {
    controller?.dispose();
    faceDetector?.close();
    super.dispose();
  }
}