これはFaceDetectorクラスを使用した基本的な例です
public myView(Context context) {
super(context);
BitmapFactory.Options BitmapFactoryOptionsbfo = new BitmapFactory.Options();
BitmapFactoryOptionsbfo.inPreferredConfig = Bitmap.Config.RGB_565;
myBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.threepoint_shooters_1990, BitmapFactoryOptionsbfo);
imageWidth = myBitmap.getWidth();
imageHeight = myBitmap.getHeight();
myFace = new FaceDetector.Face[numberOfFace];
myFaceDetect = new FaceDetector(imageWidth, imageHeight, numberOfFace);
numberOfFaceDetected = myFaceDetect.findFaces(myBitmap, myFace);
}
@Override
protected void onDraw(Canvas canvas) {
canvas.drawBitmap(myBitmap, 0, 0, null);
Paint myPaint = new Paint();
myPaint.setColor(Color.GREEN);
myPaint.setStyle(Paint.Style.STROKE);
myPaint.setStrokeWidth(3);
for (int i = 0; i < numberOfFaceDetected; i++) {
Face face = myFace[i];
PointF myMidPoint = new PointF();
face.getMidPoint(myMidPoint);
myEyesDistance = face.eyesDistance();
canvas.drawRect((int) (myMidPoint.x - myEyesDistance * 2),
(int) (myMidPoint.y - myEyesDistance * 2),
(int) (myMidPoint.x + myEyesDistance * 2),
(int) (myMidPoint.y + myEyesDistance * 2), myPaint);
}
}

ここから完全なソースコードをダウンロードしてください:
https://github.com/Jorgesys/Android_Face_Detection