Migrating from Mobile Vision to ML Kit on Android

This document covers the steps you need to take to migrate your projects from Google Mobile Vision (GMV) to ML Kit on Android.

Overall API Changes

These changes apply to all APIs:

  • GMV APIs return a SparseArray<T> result synchronously. ML Kit APIs use the Google Play services Task API to return results asynchronously.
  • GMV uses the isOperational() call in the API surface to indicate whether a module has been downloaded successfully and is ready to use. ML Kit has no such method. ML Kit throws an MlKitException.UNAVAILABLE exception if a module hasn't been downloaded. You can catch this exception and process the next frame or set a timeout and retry with the current frame.
  • GMV methods use Frame for input. ML Kit uses InputImage.
  • GMV provides MultiDetector, MultiProcessor and FocusingProcessor frameworks for performing multiple detections and results filtering. ML Kit does not provide such mechanisms, but the same functionality can be implemented by the developer if desired.

Update Gradle Imports

Update the dependencies for the ML Kit Android libraries in your module (app-level) Gradle file, which is usually app/build.gradle, according to the following table:

API GMV Artifact ML Kit Artifact
FaceDetector com.google.android.gms:play-services-vision:x.x.x com.google.android.gms:play-services-mlkit-face-detection:16.2.0
BarcodeDetector com.google.android.gms:play-services-vision:x.x.x com.google.android.gms:play-services-mlkit-barcode-scanning:16.2.1
TextRecognition com.google.android.gms:play-services-vision:x.x.x com.google.android.gms:play-services-mlkit-text-recognition:17.0.0
CameraSource com.google.android.gms:play-services-vision:x.x.x com.google.mlkit:camera:16.0.0-beta1

API Changes

This section describes corresponding GMV and ML Kit classes and methods for each Vision API, and shows how to initialize the API.

FaceDetector

Recode the initialization as shown in this example:

GMV

detector = new FaceDetector.Builder(context)
    .setMode(FaceDetector.ACCURATE_MODE)
    .setLandmarkType(FaceDetector.ALL_LANDMARKS)
    .setClassificationType(FaceDetector.ALL_CLASSIFICATIONS)
    .build();

ML Kit

FaceDetectorOptions options = new FaceDetectorOptions.Builder()
    .setPerformanceMode(FaceDetectorOptions.PERFORMANCE_MODE_ACCURATE)
    .setLandmarkMode(FaceDetectorOptions.LANDMARK_MODE_ALL)
    .setClassificationMode(FaceDetectorOptions.CLASSIFICATION_MODE_ALL)
    .build();

detector = FaceDetection.getClient(options);

Change the following class and method names:

android.gms.vision.face mlkit.vision.face
FaceDetector FaceDetector
SparseArray<Face> detect(Frame frame) Task<List<Face>> process(@NonNull InputImage image)
FaceDetector.Builder.setClassificationType(int classificationType) FaceDetectorOptions.Builder.setClassificationMode(int classificationMode)
NO_CLASSIFICATIONS, ALL_CLASSIFICATIONS CLASSIFICATION_MODE_NONE, CLASSIFICATION_MODE_ALL
FaceDetector.Builder.setLandmarkType(int landmarkType) FaceDetectorOptions.Builder.setLandmarkMode(int landmarkMode)
NO_LANDMARKS, ALL_LANDMARKS, CONTOUR_LANDMARKS LANDMARK_MODE_NONE, LANDMARK_MODE_ALL

use #setContourMode to replace GMV CONTOUR_LANDMARKS)

FaceDetector.Builder.setTrackingEnabled(boolean trackingEnabled) FaceDetectorOptions.Builder.enableTracking()
FaceDetector.Builder.setMinFaceSize(float proportionalMinFaceSize) FaceDetectorOptions.Builder.setMinFaceSize(float minFaceSize)
FaceDetector.Builder.setMode(int mode) FaceDetectorOptions.Builder.setPerformanceMode(int performanceMode)
FAST_MODE, ACCURATE_MODE PERFORMANCE_MODE_FAST, PERFORMANCE_MODE_ACCURATE
FaceDetector.Builder.setProminentFaceOnly(boolean prominentFaceOnly) This feature is covered by face contour mode.
Face Face
Contour FaceContour
Landmark FaceLandmark
Face.getContours() Face.getAllContours()
Face.getEulerY() Face.getHeadEulerAngleY()
Face.getEulerZ() Face.getHeadEulerAngleZ()
Face.getId() Face.getTrackingId()
Face.getIsLeftEyeOpenProbability() Face.getLeftEyeOpenProbability()
Face.getIsRightEyeOpenProbability() Face.getRightEyeOpenProbability()
Face.getIsSmilingProbability() Face.getSmilingProbability()
Face.getLandmarks() Face.getLandmark(int landmarkType)
Face.getPosition()
Face.getHeight()
Face.getWidth()
Face.getBoundingBox()

BarcodeDetector

Recode the initialization as shown in this example:

GMV

barcodeDetector = new BarcodeDetector.Builder(context).build());

ML Kit

barcodeScanner = BarcodeScanning.getClient();

Change the following class and method names:

android.gms.vision.barcode mlkit.vision.barcode
BarcodeDetector BarcodeScanner
SparseArray<Barcode> detect(Frame frame) Task<List<Barcode>> process(@NonNull InputImage image)
Barcode Barcode

TextRecognition

Recode the initialization as shown in this example:

GMV

textRecognizer = new TextRecognizer.Builder(context).build();

ML Kit

textRecognizer = TextRecognition.getClient(TextRecognizerOptions.DEFAULT_OPTIONS);

Change the following class and method names:

android.gms.vision.text mlkit.vision.text
TextRecognizer TextRecognizer
SparseArray<TextBlock> detect(Frame frame) Task<Text> process(@NonNull InputImage image)
SparseArray<TextBlock> Text
Line Line
TextBlock TextBlock
Element Element
getLanguage() getRecognizedLanguage()
getBoundingBox() getBoundingBox()
getCornerPoints() getCornerPoints()
TextBlock.getComponents() TextBlock.getLines()
TextBlock.getValue() TextBlock.getText()
Element.getValue() Element.getText()

CameraSource

If you use the CameraSource library provided by Google Mobile Vision, you can easily migrate to ML Kit's CameraXSource library, provided your app is running on a min sdk version >= 21.

Change the following class and method names:

android.gms.vision mlkit.vision.camera
CameraSource CameraSourceConfig
CameraSource.Builder CameraSourceConfig.Builder
CameraSource.Builder.setAutoFocusEnabled Autofocus is provided by default when using CameraX.
CameraSource.Builder.setFacing CameraSourceConfig.Builder.setCameraFacing
CameraSource.Builder.setFocusMode Autofocus is provided by default when using CameraX.
CameraSource.Builder.setRequestedFps Deprecated.
CameraSource.Builder.setRequestedPreviewSize CameraSourceConfig.Builder.setRequestedPreviewSize
CameraSource CameraXSource
new CameraSource.Builder(mContext, detector)....build(); CameraXSource(CameraSourceConfig, PreviewView)
getCameraFacing() getCameraFacing()
getPreviewSize() getPreviewSize()
release() close()
start(SurfaceHolder surfaceHolder) start() // The previewview is set in the CameraSourceConfig
start() start()
stop() stop()
Detector.Processor DetectionTaskCallback
receiveDetections(Detections<T> detections) void onDetectionTaskReceived(@NonNull Task<ResultT> detectionTask);
release() Handled internally
CameraSource.PictureCallback Deprecated
CameraSource.ShutterCallback Deprecated

Getting help

If you run into any issues, check out our Community page where we outline the channels available for getting in touch with us.