粘性物品装饰，覆盖物品RecyclerView

Question

我正在实现粘性标头项目装饰，但是我试图使标头覆盖该项目。我将代码基于timehop​​的库中。

https://github.com/timehop/sticky-headers-recyclerview

通过它的设计方式，项目装饰仍将创建一行，但是我希望它在实际列表中的高度为0。

这是我要完成的工作的一个示例。

这是当前粘性项目装饰的代码，该装饰需要创建自己的行。更改它使用的Rect可以解决很多问题，但是我无法获得正确的结果。

override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State) {
    super.getItemOffsets(outRect, view, parent, state)
    val itemPosition = parent.getChildAdapterPosition(view)
    if (itemPosition == RecyclerView.NO_POSITION) {
        return
    }
    if (mHeaderPositionCalculator.hasNewHeader(itemPosition, mOrientationProvider.isReverseLayout(parent))) {
        val header = getHeaderView(parent, itemPosition)
        setItemOffsetsForHeader(outRect, header, mOrientationProvider.getOrientation(parent))
    }
}

/**
 * Sets the offsets for the first item in a section to make room for the header view
 *
 * @param itemOffsets rectangle to define offsets for the item
 * @param header      view used to calculate offset for the item
 * @param orientation used to calculate offset for the item
 */
private fun setItemOffsetsForHeader(itemOffsets: Rect, header: View, orientation: Int) {
    mDimensionCalculator.initMargins(mTempRect, header)

    // should I modify itemOffsets here?
    if (orientation == LinearLayoutManager.VERTICAL) {
        itemOffsets.top =header.height + mTempRect.top + mTempRect.bottom
    } else {
        itemOffsets.left = header.width + mTempRect.left + mTempRect.right
    }
}

override fun onDrawOver(canvas: Canvas, parent: RecyclerView, state: RecyclerView.State) {
    super.onDrawOver(canvas, parent, state)

    val childCount = parent.childCount
    if (childCount <= 0 || mAdapter.itemCount <= 0) {
        return
    }

    for (i in 0 until childCount) {
        val itemView = parent.getChildAt(i)
        val position = parent.getChildAdapterPosition(itemView)
        if (position == RecyclerView.NO_POSITION) {
            continue
        }

        val hasStickyHeader = mHeaderPositionCalculator.hasStickyHeader(itemView, mOrientationProvider.getOrientation(parent), position)
        if (hasStickyHeader || mHeaderPositionCalculator.hasNewHeader(position, mOrientationProvider.isReverseLayout(parent))) {
            val header = mHeaderProvider.getHeader(parent, position)
            //re-use existing Rect, if any.
            var headerOffset: Rect? = mHeaderRects.get(position)
            if (headerOffset == null) {
                headerOffset = Rect()
                mHeaderRects.put(position, headerOffset)
            }


            mHeaderPositionCalculator.initHeaderBounds(headerOffset, parent, header, itemView, hasStickyHeader)
            // should I modify headerOffset here?
            mRenderer.drawHeader(parent, canvas, header, headerOffset)
        }
    }
}