RecyclerView swipe to left and show edit and delete buttons.

SwipeController.kt

package com.util

import android.annotation.SuppressLint
import android.content.Context
import android.content.res.AssetManager
import android.graphics.*
import android.support.v4.content.res.ResourcesCompat
import android.support.v7.widget.RecyclerView
import android.support.v7.widget.helper.ItemTouchHelper.Callback
import android.support.v7.widget.helper.ItemTouchHelper.*
import android.view.MotionEvent
import android.support.v7.widget.helper.ItemTouchHelper.ACTION_STATE_SWIPE
import android.view.View
import com.activity.R
import timber.log.Timber


/*
Classe de gestion du Swipe sur la RecyclerView sur ComptaActivityXYZ
*/
lateinit var assetManager : AssetManager
lateinit var context: Context
class SwipeController : Callback() {

    fun setAssetManager(assetMgr: AssetManager) {
        assetManager = assetMgr
    }

    fun setContext(contextp: Context) {
        context = contextp
    }

    override fun onSelectedChanged(viewHolder: RecyclerView.ViewHolder?, actionState: Int) {
        //Log.d("SwipeController", "onSelectedChanged")
        super.onSelectedChanged(viewHolder, actionState)
    }

    override fun getMovementFlags(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder): Int {
        //return makeMovementFlags(0, LEFT or RIGHT)
        return makeMovementFlags(0, LEFT)
    }

    override fun onMove(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder, target: RecyclerView.ViewHolder): Boolean {
        return false
    }

    override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
        // La ligne a été swipée
    }

    override fun onChildDraw(c: Canvas, recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder, dX: Float, dY: Float, actionState: Int, isCurrentlyActive: Boolean) {

        if (actionState == ACTION_STATE_SWIPE) {
            setTouchListener(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive)
        }

        drawButtons(c, viewHolder)

        val translationX: Float
        val itemViewWidth: Float = viewHolder.itemView.width.toFloat()
        if (dX > 0) {
            translationX = Math.min(-dX,  /*itemViewWidth / 2*/ buttonWidth * 2)
        } else {
            translationX = Math.max(dX, -1 * /*itemViewWidth / 2*/ buttonWidth * 2)
        }

        super.onChildDraw(c, recyclerView, viewHolder, translationX, dY, actionState, isCurrentlyActive)
    }

    @SuppressLint("ClickableViewAccessibility")
    private fun setTouchListener(c: Canvas, recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder, dX: Float, dY: Float, actionState: Int, isCurrentlyActive: Boolean) {

        recyclerView.setOnTouchListener(object : View.OnTouchListener {
            override fun onTouch(v: View, event: MotionEvent): Boolean {
                //swipeBack = event.action == MotionEvent.ACTION_CANCEL || event.action == MotionEvent.ACTION_UP
                //Timber.d("onTouch")
                //Timber.d(event.toString())
                if (event.action == MotionEvent.ACTION_DOWN) {
                    Timber.d("ACTION_DOWN")
                    val x = event.x
                    val y = event.y
                    if (x >= deleteButton.left && x <= deleteButton.right && y >= deleteButton.top && y <= deleteButton.bottom) {
                        Timber.d("Delete button clicked")
                    } else if (x >= editButton.left && x <= editButton.right && y >= editButton.top && y <= editButton.bottom) {
                        Timber.d("Edit button clicked")
                    }
                }
                return false
            }
        })
    }

    val buttonWidth = 150f
    var buttonWidthWithoutPadding: Float = 10.0F

    lateinit var deleteButton: RectF
    lateinit var editButton: RectF
    private fun drawButtons(c: Canvas, viewHolder: RecyclerView.ViewHolder) {
        buttonWidthWithoutPadding = buttonWidth - 20
        val corners = 16f

        val itemView = viewHolder.itemView
        val p = Paint()

        deleteButton = RectF(itemView.right - buttonWidthWithoutPadding, itemView.top.toFloat(), itemView.right.toFloat(), itemView.bottom.toFloat())
        p.setColor(Color.LTGRAY)
        p.style = Paint.Style.FILL_AND_STROKE
        c.drawRoundRect(deleteButton, corners, corners, p)
        drawTextDeleteButton(c, deleteButton, p)

        editButton = RectF(itemView.right - buttonWidthWithoutPadding, itemView.top.toFloat(), itemView.right - buttonWidthWithoutPadding * 2, itemView.bottom.toFloat())
        p.setColor(Color.LTGRAY)
        p.style = Paint.Style.FILL_AND_STROKE
        c.drawRoundRect(editButton, corners, corners, p)
        drawTextEditButton(c, editButton, p)
    }

    private fun drawTextEditButton(c: Canvas, button: RectF, p: Paint) {
        val font = ResourcesCompat.getFont(context, R.font.line_awesome)
        val spSize = 30
        val pxSize = spSize * context.resources.displayMetrics.scaledDensity
        val textSize = pxSize
        p.color = Color.BLACK
        p.isAntiAlias = true
        p.textSize = textSize
        p.typeface = font

        val textWidth = p.measureText("\uF2B1")
        c.drawText("\uF2B1", button.centerX() - textWidth / 2, button.centerY() + textSize / 2, p)
    }

    private fun drawTextDeleteButton(c: Canvas, button: RectF, p: Paint) {
        val font = ResourcesCompat.getFont(context, R.font.linea_basic_10)
        val spSize = 30
        val pxSize = spSize * context.resources.displayMetrics.scaledDensity
        val textSize = pxSize
        p.color = Color.BLACK
        p.isAntiAlias = true
        p.textSize = textSize
        p.typeface = font

        val textWidth = p.measureText("\uF2B1")
        c.drawText("", button.centerX() - textWidth / 2, button.centerY() + textSize / 2, p)
    }

}