Adam Hurwitz
1 min readAug 31, 2018

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This is a great high level walkthrough.

In order to implement I used the sample code created by Marcin Kitowicz here for right swiping with a background and drawable image.

The implementation is outlined in a post here. In order to implement left swipe I used the inverse left and right positioning logic.

override fun onChildDraw(c: Canvas, recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder, dX: Float, dY: Float, actionState: Int, isCurrentlyActive: Boolean) {
if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
var icon = ContextCompat.getDrawable(context!!, R.drawable.ic_save_24dp)
var iconLeft = 0
var iconRight = 0

val background: ColorDrawable
val itemView = viewHolder.itemView
val
margin = convertDpToPx(32)
val iconWidth = icon!!.intrinsicWidth
val iconHeight = icon.intrinsicHeight
val cellHeight = itemView.bottom - itemView.top
val iconTop = itemView.top + (cellHeight - iconHeight) / 2
val iconBottom = iconTop + iconHeight

// Right swipe.
if (dX > 0) {
icon = ContextCompat.getDrawable(context!!, R.drawable.ic_save_24dp)
background = ColorDrawable(Color.RED)
background.setBounds(0, itemView.getTop(), (itemView.getLeft() + dX).toInt(), itemView.getBottom())
iconLeft = margin
iconRight = margin + iconWidth
} /*Left swipe.*/ else {
icon = ContextCompat.getDrawable(context!!, R.drawable.ic_save_24dp)
background = ColorDrawable(Color.BLUE)
background.setBounds((itemView.right - dX).toInt(), itemView.getTop(), 0, itemView.getBottom())
iconLeft = itemView.right - margin - iconWidth
iconRight = itemView.right - margin
}
background.draw(c)
icon?.setBounds(iconLeft, iconTop, iconRight, iconBottom)
icon?.draw(c)
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive)
}
}

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Adam Hurwitz

An account about nothing | Researcher and product consultant