private int getNextPage(int velocity) {
        int nextPage;
        if (velocity > mMinimumVelocity) {
            nextPage = getCurrentPageFloor();
        } else if (velocity < -mMinimumVelocity) {
            nextPage = getCurrentPageCeil();
        } else {
            nextPage = getCurrentPageRound();
        }
        return Math.min(Math.max(nextPage, 0), mPageCount - 1);
    }
@param velocity
@return the page you should "land" on
app/src/main/java/home/smart/fly/animations/customview/flipview/FlipView.java