要实现Android水平RecyclerView自动滚动到中心的功能，可以按照以下步骤进行：

1. 在XML布局文件中添加一个水平RecyclerView组件：

2. 创建一个自定义的RecyclerView.Adapter，并继承自RecyclerView.Adapter。在Adapter中实现必要的方法。

3. 在Activity或Fragment中，通过findViewById找到RecyclerView控件，并设置其LayoutManager为一个自定义的LinearLayoutManager。这个LinearLayoutManager需要重写scrollHorizontallyBy方法，以实现自定义的滚动逻辑。

recyclerView = findViewById(R.id.recyclerView);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false) {
    @Override
    public int scrollHorizontallyBy(int dx, RecyclerView.Recycler recycler, RecyclerView.State state) {
        int scrolled = super.scrollHorizontallyBy(dx, recycler, state);
        if (!isScrolling) {
            centerItem();
        }
        return scrolled;
    }
};
recyclerView.setLayoutManager(linearLayoutManager);

4. 在Activity或Fragment中，为RecyclerView设置Adapter，并为其添加一个滚动监听器。在滚动监听器中，记录当前滚动状态，以便在滚动停止后执行居中操作。

MyAdapter adapter = new MyAdapter(dataList);
recyclerView.setAdapter(adapter);

recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
    @Override
    public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
        super.onScrollStateChanged(recyclerView, newState);
        isScrolling = newState != RecyclerView.SCROLL_STATE_IDLE;
        if (!isScrolling) {
            centerItem();
        }
    }
});

5. 在自定义LinearLayoutManager中，通过判断RecyclerView的子项位置，实现将RecyclerView滚动到中心位置的操作。

private void centerItem() {
    int firstVisibleItemPosition = findFirstVisibleItemPosition();
    int lastVisibleItemPosition = findLastVisibleItemPosition();
    int centerPosition = (firstVisibleItemPosition + lastVisibleItemPosition) / 2;
    View centerView = findViewByPosition(centerPosition);

    int recyclerViewCenterX = getWidth() / 2;
    int viewCenterX = (getDecoratedLeft(centerView) + getDecoratedRight(centerView)) / 2;
    int dx = viewCenterX - recyclerViewCenterX;

    smoothScrollBy(dx, 0);
}

private int findFirstVisibleItemPosition() {
    View child = findOneVisibleChild(0, getChildCount(), false, true);
    return child != null ? getPosition(child) : RecyclerView.NO_POSITION;
}

private int findLastVisibleItemPosition() {
    View child = findOneVisibleChild(getChildCount() - 1, -1, false, true);
    return child != null ? getPosition(child) : RecyclerView.NO_POSITION;
}

private View findViewByPosition(int position) {
    int childCount = getChildCount();
    for (int i = 0; i < childCount; i++) {
        View child = getChildAt(i);
        if (getPosition(child) == position) {
            return child;
        }
    }
    return null;
}

private View findOneVisibleChild(int fromIndex, int toIndex, boolean completelyVisible,
                                 boolean acceptPartiallyVisible) {
    OrientationHelper helper = OrientationHelper.createOrientationHelper(this, getOrientation());
    int start = helper.getStartAfterPadding();
    int end = helper.getEndAfterPadding();
    int next = toIndex > fromIndex ? 1 : -1;

    for (int i = fromIndex; i != toIndex; i += next) {
        View child = getChildAt(i);
        int childStart = helper.getDecoratedStart(child);
        int childEnd = helper.getDecoratedEnd(child);

        boolean childIsVisible;
        if (completelyVisible) {
            childIsVisible = childStart >= start && childEnd <= end;
        } else {
            childIsVisible = childStart < end && childEnd > start;
        }

        if (childIsVisible) {
            if (acceptPartiallyVisible) {
                return child;
            } else if (helper.getDecoratedStart(child) >= start &&