import android.content.Context
import android.util.AttributeSet
import android.view.MotionEvent
import android.webkit.WebView
import androidx.core.view.MotionEventCompat
import androidx.core.view.NestedScrollingChild
import androidx.core.view.NestedScrollingChildHelper
import androidx.core.view.ViewCompat

class NestedWebView(context: Context?, attrs: AttributeSet?, defStyleAttr: Int) :
    WebView(context!!, attrs, defStyleAttr), NestedScrollingChild {
    private var mLastY = 0
    private val mScrollOffset = IntArray(2)
    private val mScrollConsumed = IntArray(2)
    private var mNestedOffsetY = 0
    private val mChildHelper: NestedScrollingChildHelper = NestedScrollingChildHelper(this)

    constructor(context: Context?) : this(context, null) {}
    constructor(context: Context?, attrs: AttributeSet?) : this(
        context,
        attrs,
        R.attr.webViewStyle
    ) {
    }

    override fun onTouchEvent(ev: MotionEvent): Boolean {
        var returnValue = false
        val event = MotionEvent.obtain(ev)
        val action = MotionEventCompat.getActionMasked(event)
        if (action == MotionEvent.ACTION_DOWN) {
            mNestedOffsetY = 0
        }
        val eventY = event.y.toInt()
        event.offsetLocation(0f, mNestedOffsetY.toFloat())
        when (action) {
            MotionEvent.ACTION_MOVE -> {
                var totalScrollOffset = 0
                var deltaY = mLastY - eventY
                // NestedPreScroll
                if (dispatchNestedPreScroll(0, deltaY, mScrollConsumed, mScrollOffset)) {
                    totalScrollOffset += mScrollOffset[1]
                    deltaY -= mScrollConsumed[1]
                    event.offsetLocation(0f, (-mScrollOffset[1]).toFloat())
                    mNestedOffsetY += mScrollOffset[1]
                }
                returnValue = super.onTouchEvent(event)

                // NestedScroll
                if (dispatchNestedScroll(0, mScrollOffset[1], 0, deltaY, mScrollOffset)) {
                    totalScrollOffset += mScrollOffset[1]
                    event.offsetLocation(0f, mScrollOffset[1].toFloat())
                    mNestedOffsetY += mScrollOffset[1]
                    mLastY -= mScrollOffset[1]
                }
                mLastY = eventY - totalScrollOffset
            }
            MotionEvent.ACTION_DOWN -> {
                returnValue = super.onTouchEvent(event)
                mLastY = eventY
                // start NestedScroll
                startNestedScroll(ViewCompat.SCROLL_AXIS_VERTICAL)
            }
            MotionEvent.ACTION_UP, MotionEvent.ACTION_CANCEL -> {
                returnValue = super.onTouchEvent(event)
                // end NestedScroll
                stopNestedScroll()
            }
        }
        return returnValue
    }

    // Nested Scroll implements
    override fun setNestedScrollingEnabled(enabled: Boolean) {
        mChildHelper.isNestedScrollingEnabled = enabled
    }

    override fun isNestedScrollingEnabled(): Boolean {
        return mChildHelper.isNestedScrollingEnabled
    }

    override fun startNestedScroll(axes: Int): Boolean {
        return mChildHelper.startNestedScroll(axes)
    }

    override fun stopNestedScroll() {
        mChildHelper.stopNestedScroll()
    }

    override fun hasNestedScrollingParent(): Boolean {
        return mChildHelper.hasNestedScrollingParent()
    }

    override fun dispatchNestedScroll(
        dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int,
        offsetInWindow: IntArray?
    ): Boolean {
        return mChildHelper.dispatchNestedScroll(
            dxConsumed,
            dyConsumed,
            dxUnconsumed,
            dyUnconsumed,
            offsetInWindow
        )
    }

    override fun dispatchNestedPreScroll(
        dx: Int,
        dy: Int,
        consumed: IntArray?,
        offsetInWindow: IntArray?
    ): Boolean {
        return mChildHelper.dispatchNestedPreScroll(dx, dy, consumed, offsetInWindow)
    }

    override fun dispatchNestedFling(
        velocityX: Float,
        velocityY: Float,
        consumed: Boolean
    ): Boolean {
        return mChildHelper.dispatchNestedFling(velocityX, velocityY, consumed)
    }

    override fun dispatchNestedPreFling(velocityX: Float, velocityY: Float): Boolean {
        return mChildHelper.dispatchNestedPreFling(velocityX, velocityY)
    }

    init {
        isNestedScrollingEnabled = true
    }
}

在布局中：

<com.nestedscrollwebviewexample.NestedWebView
    android:id="@+id/nested_webview"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="#000000"
    android:fillViewport="true"
    android:focusable="true"
    android:isScrollContainer="false"
    android:visibility="visible"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    app:layout_scrollFlags="scroll|exitUntilCollapsed" />

问题是由NestedScrollView内部的WebView引起的。
RecyclerView覆盖了WebView，但最终WebView不再滚动。
创建一个customNestedWebView Class来实现一个NestedScrollingChild Interface。它应该是overrideonTouchEvent() Method。
修复NestedScrollView的android:nestedScrollingEnabled="true"设置。这将允许WebView在NestedScrollView内滚动。

<androidx.core.widget.NestedScrollView
    android:id="@+id/"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fillViewport=""
    android:visibility=""
    tools:visibility="gone"
    android:nestedScrollingEnabled="true">

我另外要做的是禁用硬件加速。尝试调用it.setLayerType(View.LAYER_TYPE_SOFTWARE, nul)，而不是it.setLayerType(View.LAYER_TYPE_HARDWARE, nul)。
设置WebView的NastedScrollingEnabled属性false。它将禁用滚动。在initWebView() fun中添加以下内容：

it.isNestedScrollingEnabled = false

之前测试一下，因为它可能会影响你的表现。
最后一个解决方案是使用custom WebView来实现NestedScrollingChild interface。

.kt file

class NestedWebView(context: Context, attrX: AttributeX) : WebView(context, attrX), NestedScrollingChild {
    //private val childHelper: NestedScrollingChildHelper = NestedScrollingChildHelper(this)

    init {
        //example: isNestedScrollingEnabled = true
    }

    override fun onTouchEvent(: ): Boolean {
    }

    override fun setNestedScrollingEnabled(enabled: Boolean) {
        //childHelper.isNestedScrollingEnabled = enabled
    }

    override fun isNestedScrollingEnabled(): Boolean {
        //return childHelper.isNestedScrollingEnabled
    }

    override fun startNestedScroll(axes: Int): Boolean {
        //return childHelper.startNestedScroll(axes)
    }

    override fun stopNestedScroll() {
        //childHelper.stopNestedScroll()
    }

    override fun hasNestedScrollingParent(): Boolean {
        //return childHelper.hasNestedScrollingParent()
    }

        //dispatchNestedScroll
        //dispatchPreScroll
        //dispatchNestedFling
        //dispatchNestedPreFling

    }

}

.XML layout

<com.example.myapp.NestedWebView
    android:id="@+id/"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

初始化并使用带有reg WebView的定制NestedWebView示例。