public class GalleryLayoutManager extends RecyclerView.LayoutManager {
private int totalWidth;
private int scrollOffset;
private SparseArray<Rect> allRect;

public GalleryLayoutManager() {
    allRect = new SparseArray<>();
}

@Override
public RecyclerView.LayoutParams generateDefaultLayoutParams() {
    return new RecyclerView.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
}

@Override
public boolean canScrollHorizontally() {
    return true;
}

@Override
public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
    calculateChildrenSize(recycler);
    recyclerAndFillView(recycler, state);
}

private void calculateChildrenSize(RecyclerView.Recycler recycler) {
    totalWidth = (int) (getWidth() * 0.06);
    for (int i = 0; i < getItemCount(); i++) {
        View v = recycler.getViewForPosition(i);
        addView(v);
        measureChildWithMargins(v, (int) (getWidth() * 0.2), (int) (getHeight() * 0.1));
        calculateItemDecorationsForChild(v, new Rect());
        int width = getDecoratedMeasuredWidth(v);
        int height = getDecoratedMeasuredHeight(v);
        Rect childRect = allRect.get(i);
        if (null == childRect) {
            childRect = new Rect();
        }
        childRect.set(totalWidth, (getHeight() - height) / 2, totalWidth + width, (getHeight() + height) / 2);
        totalWidth += width;
        allRect.put(i, childRect);
    }
    totalWidth += getWidth() * 0.1;
}

@Override
public int scrollHorizontallyBy(int dx, RecyclerView.Recycler recycler, RecyclerView.State state) {
    if (scrollOffset + dx < 0) {
        dx = -scrollOffset;
    } else if (scrollOffset + dx > totalWidth - getWidth()) {
        dx = totalWidth - getWidth() - scrollOffset;
    }
    offsetChildrenHorizontal(-dx);
    recyclerAndFillView(recycler, state);
    scrollOffset += dx;
    return dx;
}

private void recyclerAndFillView(RecyclerView.Recycler recycler, RecyclerView.State state) {
    if (getItemCount() == 0 || state.isPreLayout()) return;
    int w = getWidth();
    int h = getHeight();
    detachAndScrapAttachedViews(recycler);
    Rect displayRect = new Rect(scrollOffset, 0, scrollOffset + w, h);

    float scale;
    for (int i = 0; i < getItemCount(); i++) {
        if (Rect.intersects(displayRect, allRect.get(i))) {
            View v = recycler.getViewForPosition(i);
            measureChildWithMargins(v, (int) (getWidth() * 0.3), (int) (getHeight() * 0.1));
            addView(v);

            Rect rect = allRect.get(i);
            scale = (float) (rect.left + getWidth() * 0.35 - getWidth() * 0.5 - scrollOffset);
            scale /= translate();
            scale = Math.abs(scale);
            v.setAlpha(1 - scale * 0.5f);
            scale *= 1 / 20f;
            scale = 1 - scale;
            v.setScaleX(scale);
            v.setScaleY(scale);
            layoutDecorated(v, rect.left - scrollOffset, rect.top, rect.right - scrollOffset, rect.bottom);
        }
    }
}

private float translate() {
    return (float) (getWidth() * 0.7);
}
}

自定义LayoutManager的步骤：

1. 自定义itemView的位置
2. 滑动实现
3. itemView复用实现