Face detection in Android

You must add Google Play Service libs

activity_layout

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 

 xmlns:tools="http://schemas.android.com/tools" 

 android:layout_width="match_parent" 

 android:layout_height="match_parent" 

 android:orientation="vertical" 

 tools:context=".MainActivity">
    
    <package.FaceOverlayView 

    android:id="@+id/face_overlay" 

    android:layout_width="wrap_content"

    android:layout_height="wrap_content" />

</LinearLayout>

MainActivity 

public class MainActivity extends AppCompatActivity {

    private FaceOverlayView mFaceOverlayView;

    @Override    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mFaceOverlayView = (FaceOverlayView) findViewById(R.id.face_overlay);
        mFaceOverlayView.setBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.img_1111));
    }
} 

FaceOverlayView class

public class FaceOverlayView extends View {

    private Bitmap mBitmap;
    private SparseArray<Face> mFaces;

    public FaceOverlayView(Context context) {
        this(context, null);
    }

    public FaceOverlayView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public FaceOverlayView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    public void setBitmap(Bitmap bitmap) {
        mBitmap = bitmap;
        FaceDetector detector = new FaceDetector.Builder(getContext())
                .setTrackingEnabled(true)
                .setLandmarkType(FaceDetector.ALL_LANDMARKS)
                .setMode(FaceDetector.ACCURATE_MODE)
                .build();

        if (!detector.isOperational()) {
            //Handle contingency        } else {
            Frame frame = new Frame.Builder().setBitmap(bitmap).build();
            mFaces = detector.detect(frame);
            detector.release();
        }
        logFaceData();
        invalidate();
    }

    @Override    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        if ((mBitmap != null) && (mFaces != null)) {
            double scale = drawBitmap(canvas);
//            drawFaceLandmarks(canvas, scale); 

            drawFaceBox(canvas,scale);
        }
    }

    private double drawBitmap(Canvas canvas) {
        double viewWidth = canvas.getWidth();
        double viewHeight = canvas.getHeight();
        double imageWidth = mBitmap.getWidth();
        double imageHeight = mBitmap.getHeight();
        double scale = Math.min(viewWidth / imageWidth, viewHeight / imageHeight);

        Rect destBounds = new Rect(0, 0, (int) (imageWidth * scale), (int) (imageHeight * scale));
        canvas.drawBitmap(mBitmap, null, destBounds, null);
        return scale;
    }

    private void drawFaceBox(Canvas canvas, double scale) {
        //This should be defined as a member variable rather than 

 //being created on each onDraw request, but left here for 

//emphasis. 

        Paint paint = new Paint();
        paint.setColor(Color.GREEN);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeWidth(5);

        float left = 0;
        float top = 0;
        float right = 0;
        float bottom = 0;
        // mFaces.size() == 0 , dont detect face->handle here 

 for (int i = 0; i < mFaces.size(); i++) {
            Face face = mFaces.valueAt(i);

            left = (float) (face.getPosition().x * scale);
            top = (float) (face.getPosition().y * scale);
            right = (float) scale * (face.getPosition().x + face.getWidth());
            bottom = (float) scale * (face.getPosition().y + face.getHeight());

            canvas.drawRect(left, top, right, bottom, paint);
        }
    }

    private void drawFaceLandmarks(Canvas canvas, double scale) {
        Paint paint = new Paint();
        paint.setColor(Color.GREEN);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeWidth(5);

        for (int i = 0; i < mFaces.size(); i++) {
            Face face = mFaces.valueAt(i);

            for (Landmark landmark : face.getLandmarks()) {
                int cx = (int) (landmark.getPosition().x * scale);
                int cy = (int) (landmark.getPosition().y * scale);
                canvas.drawCircle(cx, cy, 10, paint);
            }

        }
    }

    private void logFaceData() {
        float smilingProbability;
        float leftEyeOpenProbability;
        float rightEyeOpenProbability;
        float eulerY;
        float eulerZ;
        for (int i = 0; i < mFaces.size(); i++) {
            Face face = mFaces.valueAt(i);

            smilingProbability = face.getIsSmilingProbability();
            leftEyeOpenProbability = face.getIsLeftEyeOpenProbability();
            rightEyeOpenProbability = face.getIsRightEyeOpenProbability();
            eulerY = face.getEulerY();
            eulerZ = face.getEulerZ();

            Log.e("Tuts+ Face Detection", "Smiling: " + smilingProbability);
            Log.e("Tuts+ Face Detection", "Left eye open: " + leftEyeOpenProbability);
            Log.e("Tuts+ Face Detection", "Right eye open: " + rightEyeOpenProbability);
            Log.e("Tuts+ Face Detection", "Euler Y: " + eulerY);
            Log.e("Tuts+ Face Detection", "Euler Z: " + eulerZ);
        }
    }
}