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

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

public ScrollViewGroup(Context context, AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  mScroller = new Scroller(context);
}

@Override
public void computeScroll() {
  super.computeScroll();
  if (mScroller.computeScrollOffset()) {
    scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
    postInvalidate();
  }
}

mScroller.startScroll (int startX, int startY, int dx, int dy);
invalidate();

public void scrollTo(int x, int y) {
  if (mScrollX != x || mScrollY != y) {
    int oldX = mScrollX;
    int oldY = mScrollY;
    mScrollX = x;
    mScrollY = y;
    invalidateParentCaches();
    onScrollChanged(mScrollX, mScrollY, oldX, oldY);
    if (!awakenScrollBars()) {
      postInvalidateOnAnimation();
    }
  }
}

public void scrollBy(int x, int y) {
  scrollTo(mScrollX + x, mScrollY + y);
}

public Scroller(Context context, Interpolator interpolator, boolean flywheel) {
  mFinished = true;
  if (interpolator == null) {
    mInterpolator = new ViscousFluidInterpolator();
  } else {
    mInterpolator = interpolator;
  }
  mPpi = context.getResources().getDisplayMetrics().density * 160.0f;
  mDeceleration = computeDeceleration(ViewConfiguration.getScrollFriction());
  mFlywheel = flywheel;

  mPhysicalCoeff = computeDeceleration(0.84f); // look and feel tuning
}

public void startScroll(int startX, int startY, int dx, int dy, int duration) {
  mMode = SCROLL_MODE;
  mFinished = false;
  mDuration = duration;
  mStartTime = AnimationUtils.currentAnimationTimeMillis();
  mStartX = startX;
  mStartY = startY;
  mFinalX = startX + dx;
  mFinalY = startY + dy;
  mDeltaX = dx;
  mDeltaY = dy;
  mDurationReciprocal = 1.0f / (float) mDuration;
}

/**
 * Called by a parent to request that a child update its values for mScrollX
 * and mScrollY if necessary. This will typically be done if the child is
 * animating a scroll using a {@link android.widget.Scroller Scroller}
 * object.
 */
public void computeScroll() {
}

/**
 * Call this when you want to know the new location. If it returns true,
 * the animation is not yet finished.
 */ 
public boolean computeScrollOffset() {
  if (mFinished) {
    return false;
  }

  int timePassed = (int)(AnimationUtils.currentAnimationTimeMillis() - mStartTime);

  if (timePassed < mDuration) {
    switch (mMode) {
    case SCROLL_MODE:
      final float x = mInterpolator.getInterpolation(timePassed * mDurationReciprocal);
      mCurrX = mStartX + Math.round(x * mDeltaX);
      mCurrY = mStartY + Math.round(x * mDeltaY);
      break;
    case FLING_MODE:
      final float t = (float) timePassed / mDuration;
      final int index = (int) (NB_SAMPLES * t);
      float distanceCoef = 1.f;
      float velocityCoef = 0.f;
      if (index < NB_SAMPLES) {
        final float t_inf = (float) index / NB_SAMPLES;
        final float t_sup = (float) (index + 1) / NB_SAMPLES;
        final float d_inf = SPLINE_POSITION[index];
        final float d_sup = SPLINE_POSITION[index + 1];
        velocityCoef = (d_sup - d_inf) / (t_sup - t_inf);
        distanceCoef = d_inf + (t - t_inf) * velocityCoef;
      }

      mCurrVelocity = velocityCoef * mDistance / mDuration * 1000.0f;
      
      mCurrX = mStartX + Math.round(distanceCoef * (mFinalX - mStartX));
      // Pin to mMinX <= mCurrX <= mMaxX
      mCurrX = Math.min(mCurrX, mMaxX);
      mCurrX = Math.max(mCurrX, mMinX);
      
      mCurrY = mStartY + Math.round(distanceCoef * (mFinalY - mStartY));
      // Pin to mMinY <= mCurrY <= mMaxY
      mCurrY = Math.min(mCurrY, mMaxY);
      mCurrY = Math.max(mCurrY, mMinY);

      if (mCurrX == mFinalX && mCurrY == mFinalY) {
        mFinished = true;
      }

      break;
    }
  }
  else {
    mCurrX = mFinalX;
    mCurrY = mFinalY;
    mFinished = true;
  }
  return true;
}