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:17.1.0`
BarcodeDetector	`com.google.android.gms:play-services-vision:x.x.x`	`com.google.android.gms:play-services-mlkit-barcode-scanning:18.3.1`
TextRecognition	`com.google.android.gms:play-services-vision:x.x.x`	`com.google.android.gms:play-services-mlkit-text-recognition:19.0.1`
CameraSource	`com.google.android.gms:play-services-vision:x.x.x`	`com.google.mlkit:camera:16.0.0-beta3`

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.