DragAndDrop.kt

package com.kedia.swipetodelete

import android.view.GestureDetector
import android.view.MotionEvent
import android.view.View
import androidx.recyclerview.widget.ItemTouchHelper
import androidx.recyclerview.widget.RecyclerView

object DragAndDrop: View.OnTouchListener, GestureDetector.OnGestureListener {

    private lateinit var gestureDetector: GestureDetector
    private lateinit var touchHelper: ItemTouchHelper

    private lateinit var holder: RecyclerView.ViewHolder

    fun RecyclerView.addDragToSwipe(listener: onDragged? = null): ItemTouchHelper {

        val itemTouchCallback = object : ItemTouchHelper.Callback() {
            override fun onSelectedChanged(viewHolder: RecyclerView.ViewHolder?, actionState: Int) {
                super.onSelectedChanged(viewHolder, actionState)
                if (actionState == ItemTouchHelper.ACTION_STATE_DRAG) {
                    viewHolder!!.itemView.alpha = 0.2f
                }
            }

            override fun clearView(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder) {
                super.clearView(recyclerView, viewHolder)
                viewHolder.itemView.alpha = 1f
            }

            override fun isItemViewSwipeEnabled(): Boolean {
                return false
            }

            override fun isLongPressDragEnabled(): Boolean {
                return false
            }

            override fun getMovementFlags(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder): Int {
                holder = viewHolder
                holder.itemView.setGestures()
                val drags =
                    ItemTouchHelper.START or ItemTouchHelper.END or ItemTouchHelper.UP or ItemTouchHelper.DOWN
                return makeMovementFlags(
                    drags,
                    0
                )
            }

            override fun onMove(
                recyclerView: RecyclerView,
                viewHolder: RecyclerView.ViewHolder,
                target: RecyclerView.ViewHolder
            ): Boolean {
                listener?.onPositionDragged(viewHolder.adapterPosition, target.adapterPosition)
                adapter?.notifyItemMoved(viewHolder.adapterPosition, target.adapterPosition)
                return true
            }

            override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {}

        }


        val itemTouchHelper = ItemTouchHelper(itemTouchCallback)
        itemTouchHelper.attachToRecyclerView(this)
        touchHelper = itemTouchHelper
        return itemTouchHelper
    }


    fun View.setGestures() {
        gestureDetector = GestureDetector(this.context, this@DragAndDrop)
        this.setOnTouchListener(this@DragAndDrop)
    }

    override fun onTouch(v: View?, event: MotionEvent?): Boolean {
        gestureDetector.onTouchEvent(event)
        return true
    }

    override fun onDown(e: MotionEvent?): Boolean {
        return false
    }

    override fun onShowPress(e: MotionEvent?) {}

    override fun onSingleTapUp(e: MotionEvent?): Boolean {

        return false
    }

    override fun onScroll(
        e1: MotionEvent?,
        e2: MotionEvent?,
        distanceX: Float,
        distanceY: Float
    ): Boolean {
        return false
    }

    override fun onLongPress(e: MotionEvent?) {
        touchHelper.startDrag(holder)
    }

    override fun onFling(
        e1: MotionEvent?,
        e2: MotionEvent?,
        velocityX: Float,
        velocityY: Float
    ): Boolean {
        return false
    }

    interface onDragged {
        fun onPositionDragged(positionStart: Int, positionEnd: Int)
    }

}