我怎么才能从firebase ML Kit人脸检测中获得情绪呢？

FirebaseVisionFaceDetectorOptions options =
    new FirebaseVisionFaceDetectorOptions.Builder()
        .setPerformanceMode(FirebaseVisionFaceDetectorOptions.FAST)
        .setLandmarkMode(FirebaseVisionFaceDetectorOptions.NO_LANDMARKS)
        .setClassificationMode(FirebaseVisionFaceDetectorOptions.ALL_CLASSIFICATIONS)
        .build();

FirebaseVisionFaceDetector detector = FirebaseVision.getInstance()
    .getVisionFaceDetector(options);

FirebaseVisionImage image = FirebaseVisionImage.fromBitmap(bitmap);

Task<List<FirebaseVisionFace>> result =
    detector.detectInImage(image)
        .addOnSuccessListener(
            new OnSuccessListener<List<FirebaseVisionFace>>() {
                @Override
                public void onSuccess(List<FirebaseVisionFace> faces) {
                    // 在这里处理检测到的人脸
                    for (FirebaseVisionFace face : faces) {
                        // 获取情绪信息
                        FirebaseVisionFaceEmotion emotion = face.getSmilingProbability();
                        if (emotion != null) {
                            float smileProb = emotion.getSmilingProbability();
                            // 在这里可以根据情绪信息进行相应的处理
                        }
                    }
                }
            })
        .addOnFailureListener(
            new OnFailureListener() {
                @Override
                public void onFailure(@NonNull Exception e) {
                    // 处理错误情况
                }
            });