实现RecyclerView的sticky吸顶功能，不通过ItemDecoration实现，解决click等各种event事件问题，解决webview无法渲染问题，但需要外层包一个FrameLayout

RecyclerViewSticky.kt

import android.graphics.Canvas
import android.util.Log
import android.view.View
import android.view.ViewGroup
import android.widget.FrameLayout
import androidx.recyclerview.widget.GridLayoutManager
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import androidx.recyclerview.widget.RecyclerView.OnScrollListener
import androidx.recyclerview.widget.StaggeredGridLayoutManager

class RecyclerViewSticky(private val recyclerView: RecyclerView, private val predicate: (RecyclerView, Int) -> Boolean) : OnScrollListener() {

    companion object {
        fun bindSticky(recyclerView: RecyclerView, predicate: (RecyclerView, Int) -> Boolean) {
            LokiSticky(recyclerView, predicate).attach()
        }
    }

    private var mAdapter: RecyclerView.Adapter<*>? = null

    var pinView: View? = null

    var pinPos: Int = -1

    private val resetTask = Runnable {
        doReset()
    }

    fun attach() {
        recyclerView.addOnScrollListener(this)
        recyclerView.addOnLayoutChangeListener { v, left, top, right, bottom, oldLeft, oldTop, oldRight, oldBottom ->
            checkCache(recyclerView)
        }
    }

    override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
        super.onScrolled(recyclerView, dx, dy)
        tryPinView(recyclerView)
    }

    private fun hidePinView() {
        pinView?.visibility = View.GONE
    }

    private fun showPinView() {
        pinView?.visibility = View.VISIBLE
    }

    private fun destroyPinView() {
        pinView?.parent?.let {
            (it as ViewGroup).removeView(pinView)
            pinView = null
        }
    }

    private fun tryPinView(recyclerView: RecyclerView) {
        val firstVisiblePos = findFirstVisiblePosition(recyclerView.layoutManager)
        val pinPos = findPinnedHeaderPosition(recyclerView, firstVisiblePos)

        if (pinPos < 0 || firstVisiblePos < pinPos) {
            hidePinView()
            return
        }

        if (this.pinPos == pinPos && pinView != null) {
            showPinView()
            return
        }

        destroyPinView()

        val type = recyclerView.adapter?.getItemViewType(pinPos)

        val holder = recyclerView.adapter?.createViewHolder(recyclerView, type!!)
        recyclerView.adapter?.bindViewHolder(holder!!, pinPos)
        holder?.itemView.let {
            var layout: FrameLayout? = null
            var vp = recyclerView.parent
            while (vp != null) {
                if (vp is FrameLayout) {
                    layout = vp
                    break
                }
                vp = vp.parent
            }
            if (layout != null) {
                pinView = it
                this.pinPos = pinPos
                layout.addView(
                    pinView,
                    ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT)
                )
            }
        }
    }

    private fun findPinnedHeaderPosition(rv: RecyclerView, fromPosition: Int): Int {
        val adapter = rv.adapter
        if (adapter != null) {
            for (position in fromPosition downTo 0) {
                if (predicate.invoke(rv, position)) {
                    return position
                }
            }
        }

        return -1
    }

    private fun findFirstVisiblePosition(layoutManager: RecyclerView.LayoutManager?): Int {
        var firstVisiblePosition = 0
        if (layoutManager is GridLayoutManager) {
            firstVisiblePosition = layoutManager.findFirstVisibleItemPosition()
        } else if (layoutManager is LinearLayoutManager) {
            firstVisiblePosition = layoutManager.findFirstVisibleItemPosition()
        } else if (layoutManager is StaggeredGridLayoutManager) {
            val into = IntArray(layoutManager.spanCount)
            layoutManager.findFirstVisibleItemPositions(into)
            firstVisiblePosition = Int.MAX_VALUE
            for (pos in into) {
                firstVisiblePosition = Math.min(pos, firstVisiblePosition)
            }
        }
        return firstVisiblePosition
    }

    private fun checkCache(parent: RecyclerView) {
        val adapter = parent.adapter
        if (mAdapter !== adapter) {
            reset()
            mAdapter = adapter
            if (mAdapter != null) {
                (mAdapter as RecyclerView.Adapter<*>).registerAdapterDataObserver(object : RecyclerView.AdapterDataObserver() {
                    override fun onChanged() {
                        super.onChanged()
                        reset()
                    }

                    override fun onItemRangeChanged(positionStart: Int, itemCount: Int) {
                        super.onItemRangeChanged(positionStart, itemCount)
                        reset()
                    }

                    override fun onItemRangeChanged(positionStart: Int, itemCount: Int, payload: Any?) {
                        super.onItemRangeChanged(positionStart, itemCount, payload)
                        reset()
                    }

                    override fun onItemRangeInserted(positionStart: Int, itemCount: Int) {
                        super.onItemRangeInserted(positionStart, itemCount)
                        reset()
                    }

                    override fun onItemRangeRemoved(positionStart: Int, itemCount: Int) {
                        super.onItemRangeRemoved(positionStart, itemCount)
                        reset()
                    }

                    override fun onItemRangeMoved(fromPosition: Int, toPosition: Int, itemCount: Int) {
                        super.onItemRangeMoved(fromPosition, toPosition, itemCount)
                        reset()
                    }
                })
            }
        }
    }

    private fun reset() {
        recyclerView.removeCallbacks(resetTask)
        recyclerView.post(resetTask)
    }

    private fun doReset() {
        pinPos = -1
        destroyPinView()
        tryPinView(recyclerView)
    }
}