如何在 RecyclerView 的适配器本身中获取以前的 position？

Question

I'm having a RecyclerView, inside its layout there's a view "tvDateGrouped", I want it to be displayed only when the current position date and previous position date are not same. Below is the code I tried, but it isn't working

This Code is inside the adapter class, inside the onBind() method

  if (position != 0 && transactions[position].date == 
    transactions[holder.adapterPosition.minus(1)].date) {
                holder.view.tvDateGrouped.visibility = View.GONE
            } else {
                holder.view.tvDateGrouped.text = formattedDateString
            }

and if I change position,= 1 , the app crashes

below is the code when app crashes

  if (position != 1 && transactions[position].date == 
        transactions[holder.adapterPosition.minus(1)].date) {
                    holder.view.tvDateGrouped.visibility = View.GONE
                } else {
                    holder.view.tvDateGrouped.text = formattedDateString
                }

Edit: I've changed the code as the below, but the app is crashing now-

if ((transactions[position].date == transactions[position - 1].date) && 
(position > 0)) {
    holder.view.tvDateGrouped.visibility = View.GONE
} else {
    holder.view.tvDateGrouped.visibility = View.VISIBLE
    holder.view.tvDateGrouped.text = formattedDateString
}

Please Help me resolve this issue

Answer 1

Your crash is simply happening when position is 0 then position - 1 will be -1 which is an invalid index and you will get a runtime exception.

But why the first solution isn't working? One clear reason is because you've forgotten to make the text visible again. So change it to:

 if (position > 0 && transactions[position].date == transactions[position - 1].date) {
    holder.view.tvDateGrouped.visibility = View.GONE
} else {
    holder.view.tvDateGrouped.visibility = View.VISIBLE
    holder.view.tvDateGrouped.text = formattedDateString
}