public class ScrollerLayout extends ViewGroup {

    private Scroller mScroller;
    private int currentDisplayPosition = 0;

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

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        int childCount = getChildCount();
        for (int i = 0; i < childCount; i++) {
            View childView = getChildAt(i);
            measureChild(childView, widthMeasureSpec, heightMeasureSpec);
        }
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        if (changed) {
            int childCount = getChildCount();
            for (int i = 0; i < childCount; i++) {
                View childView = getChildAt(i);
                int childMeasuredWidth = childView.getMeasuredWidth();

                childView.layout(
                        i * childMeasuredWidth,
                        0,
                        (i + 1) * childMeasuredWidth,
                        childView.getMeasuredHeight());
            }
        }
    }

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

    /**
     * 滚动至指定位置
     */
    public void smoothScrollToPosition(int position){
        int childCount = getChildCount();
        if (position > childCount || position < 0) {
            return;
        }

        currentDisplayPosition = position;
        int dx = position * getWidth() - getScrollX();
        mScroller.startScroll(getScrollX(), 0, dx, 0);
        invalidate();
    }

    /**
     * 滚动至下一个
     */
    public void smoothScrollToPrevious(){
        smoothScrollToPosition(--currentDisplayPosition);
    }

    /**
     * 滚动至上一个
     */
    public void smoothScrollToNext(){
        smoothScrollToPosition(++currentDisplayPosition);
    }

    /**
     * @return 当前显示位置
     */
    public int getCurrentPosition(){
        return currentDisplayPosition;
    }
}