Flutter中Google ML Kit检测眼睛开合概率始终为null的问题

你当前使用的是默认配置的FaceDetector，默认情况下不会计算并返回眼睛开合概率，所以leftEyeOpenProbability和rightEyeOpenProbability会返回null。

需要创建FaceDetectorOptions并启用眼睛开合概率检测，再用这个配置初始化FaceDetector。

修改后的完整代码如下：

Future<void> detectFacesInImage(String imagePath) async {
  final File imageFile = File(imagePath);
  final InputImage inputImage = InputImage.fromFile(imageFile);
  
  // 配置FaceDetector，启用眼睛开合概率检测
  final options = FaceDetectorOptions(
    enableEyeOpenProbability: true,
    // 可选：启用其他检测特征，比如微笑概率
    // enableSmileProbability: true,
    // 可选：切换到精准模式，提升检测精度但速度稍慢
    // performanceMode: FaceDetectorMode.accurate,
  );
  
  final FaceDetector faceDetector = GoogleMlKit.vision.faceDetector(options);

  try {
    final List<Face> faces = await faceDetector.processImage(inputImage);
    if (faces.isEmpty) {
      print('No faces detected in the image');
      showCustomSnackbar(title: 'error', message: 'No faces detected in the image', backgroundColor: Colors.red);
      return;
    }

    for (Face face in faces) {
      print('enter in face');
      final double? leftEyeOpenProbability = face.leftEyeOpenProbability;
      if (leftEyeOpenProbability != null) {
        print('Left eye open probability: $leftEyeOpenProbability');
      } else {
        print('Left eye open probability: $leftEyeOpenProbability');
        showCustomSnackbar(title: 'error', message: 'Left eye open probability not available', backgroundColor: Colors.red);
        return;
      }
      
      final double? rightEyeOpenProbability = face.rightEyeOpenProbability;
      if (rightEyeOpenProbability != null) {
        print('Right eye open probability: $rightEyeOpenProbability');
      } else {
        print('Right eye open probability: $rightEyeOpenProbability');
        showCustomSnackbar(title: 'error', message: 'Right eye open probability not available', backgroundColor: Colors.red);
        return;
      }
    }
  } catch (e) {
    showCustomSnackbar(title: 'error', message: 'Error detecting faces', backgroundColor: Colors.red);
    print('Error detecting faces: $e');
  } finally {
    faceDetector.close();
  }
}

• 确保你的Google ML Kit依赖版本为最新，避免版本兼容问题导致配置不生效
• 若检测结果精度不足，可尝试将performanceMode设置为FaceDetectorMode.accurate，以牺牲少量速度为代价提升检测准确性

内容的提问来源于stack exchange，提问作者Sohail Anwar