NestedCoordinatorLayout.kt

import android.content.Context
import android.util.AttributeSet
import android.view.View
import androidx.coordinatorlayout.widget.CoordinatorLayout
import androidx.core.view.NestedScrollingChild3
import androidx.core.view.NestedScrollingChildHelper

class NestedCoordinatorLayout @JvmOverloads constructor(
    context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
) : CoordinatorLayout(context, attrs, defStyleAttr), NestedScrollingChild3 {

    private val nestedScrollingChildHelper: NestedScrollingChildHelper = NestedScrollingChildHelper(this)

    init {
        isNestedScrollingEnabled = true
    }

    override fun onStartNestedScroll(child: View, target: View, axes: Int, type: Int): Boolean =
        super.onStartNestedScroll(child, target, axes, type).or(startNestedScroll(axes, type))

    override fun onNestedFling(target: View, velocityX: Float, velocityY: Float, consumed: Boolean): Boolean =
        super.onNestedFling(target, velocityX, velocityY, consumed).or(
            dispatchNestedFling(
                velocityX,
                velocityY,
                consumed
            )
        )

    override fun onNestedPreScroll(target: View, dx: Int, dy: Int, consumed: IntArray, type: Int) {
        super.onNestedPreScroll(target, dx, dy, consumed, type)

        if (consumed[1] == 0) {
            dispatchNestedPreScroll(dx, dy, consumed, null, type)
        }
    }

    override fun onNestedScroll(
        target: View,
        dxConsumed: Int,
        dyConsumed: Int,
        dxUnconsumed: Int,
        dyUnconsumed: Int,
        type: Int,
        consumed: IntArray
    ) {
        super.onNestedScroll(target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed, type, consumed)
        if (consumed[1] == 0) {
            dispatchNestedScroll(dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed, null, type, consumed)
        }
    }

    override fun onNestedPreFling(target: View, velocityX: Float, velocityY: Float): Boolean =
        super.onNestedPreFling(target, velocityX, velocityY).or(dispatchNestedPreFling(velocityX, velocityY))

    override fun onStopNestedScroll(target: View, type: Int) {
        super.onStopNestedScroll(target, type)
        stopNestedScroll(type)
    }

    override fun dispatchNestedScroll(
        dxConsumed: Int,
        dyConsumed: Int,
        dxUnconsumed: Int,
        dyUnconsumed: Int,
        offsetInWindow: IntArray?,
        type: Int
    ): Boolean = nestedScrollingChildHelper.dispatchNestedScroll(
        dxConsumed,
        dyConsumed,
        dxUnconsumed,
        dyUnconsumed,
        offsetInWindow,
        type
    )

    override fun dispatchNestedScroll(
        dxConsumed: Int,
        dyConsumed: Int,
        dxUnconsumed: Int,
        dyUnconsumed: Int,
        offsetInWindow: IntArray?
    ): Boolean = nestedScrollingChildHelper.dispatchNestedScroll(
        dxConsumed,
        dyConsumed,
        dxUnconsumed,
        dyUnconsumed,
        offsetInWindow
    )

    override fun dispatchNestedScroll(
        dxConsumed: Int,
        dyConsumed: Int,
        dxUnconsumed: Int,
        dyUnconsumed: Int,
        offsetInWindow: IntArray?,
        type: Int,
        consumed: IntArray
    ) {
        nestedScrollingChildHelper.dispatchNestedScroll(
            dxConsumed,
            dyConsumed,
            dxUnconsumed,
            dyUnconsumed,
            offsetInWindow,
            type,
            consumed
        )
    }

    override fun isNestedScrollingEnabled(): Boolean = nestedScrollingChildHelper.isNestedScrollingEnabled

    override fun dispatchNestedPreScroll(
        dx: Int,
        dy: Int,
        consumed: IntArray?,
        offsetInWindow: IntArray?,
        type: Int
    ): Boolean = nestedScrollingChildHelper.dispatchNestedPreScroll(dx, dy, consumed, offsetInWindow, type)

    override fun dispatchNestedPreScroll(dx: Int, dy: Int, consumed: IntArray?, offsetInWindow: IntArray?): Boolean =
        nestedScrollingChildHelper.dispatchNestedPreScroll(dx, dy, consumed, offsetInWindow)

    override fun stopNestedScroll(type: Int) {
        nestedScrollingChildHelper.stopNestedScroll(type)
    }

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

    override fun hasNestedScrollingParent(type: Int): Boolean =
        nestedScrollingChildHelper.hasNestedScrollingParent(type)

    override fun hasNestedScrollingParent(): Boolean = nestedScrollingChildHelper.hasNestedScrollingParent()

    override fun dispatchNestedPreFling(velocityX: Float, velocityY: Float): Boolean =
        nestedScrollingChildHelper.dispatchNestedPreFling(velocityX, velocityY)

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

    override fun dispatchNestedFling(velocityX: Float, velocityY: Float, consumed: Boolean): Boolean =
        nestedScrollingChildHelper.dispatchNestedFling(velocityX, velocityY, consumed)

    override fun startNestedScroll(axes: Int, type: Int): Boolean =
        nestedScrollingChildHelper.startNestedScroll(axes, type)

    override fun startNestedScroll(axes: Int): Boolean = nestedScrollingChildHelper.startNestedScroll(axes)
}