Cannot format given Object as a Number in Kotlin

Question

An error occurred while using the ConverPrice function as follows for information about the price.

The price of the item in the recycler view adapter onBindViewHolder.

As a result of debugging, the error occurs in the following code.

priceText = "${dec.format(priceMin)} ~ ${dec.format(priceMax)}"

Please check my code and answer.

        override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {

            when (holder) {
                is DataViewHolder -> {
                    val item = dataList[position]

                    item.price.let {
                        holder.price.text = ConvertPrice(item, holder.price)
                    }

                }
            }
        }

fun ConvertPrice(productDetail: ProductDetail?, tv: TextView? = null, setPrice: Boolean = false): String {
    val disableColor = Color.parseColor("#aaaaaa")
    val enableColor = Color.parseColor("#3692ff")

    tv?.setTextColor(disableColor)

    if (ProductDetail != null) {
        val priceMin = productDetail.priceMin
        val priceMax = productDetail.priceMax
        var priceText = ""

        val dec = DecimalFormat("##,###")

        productDetail.enabledRetail?.let {
            if (productDetail.enabledRetail == true) {
                if (setPrice) {
                    priceText = if (priceMin == null || priceMax == null) {
                        "No pricing information"
                    } else {
                        "${dec.format(priceMin)} ~ ${dec.format(priceMax)}"
                    }
                    tv?.setTextColor(disableColor)
                }
                else {
                    priceText = dec.format(wineDetail.price).toString()
                    tv?.setTextColor(enableColor)
                }
                return priceText
            } else if (productDetail.cntRating!! > 0) {
                if ((priceMin == null && priceMax == null) || (priceMin == 0 && priceMax == 0)) {
                    priceText = "No pricing information"
                } else {
                    priceText =
                        "${dec.format(priceMin)} ~ ${dec.format(priceMax)}"
                    tv?.setTextColor(disableColor)
                }
                return priceText
            }
        }
    }
    return "No pricing information"
}

Answer 1

DecimalFormat.format() only works fine with long or double. You should convert "priceMin" and "priceMax" to Long.

val priceMin = productDetail.priceMin.toLong()
val priceMax = productDetail.priceMax.toLong()

I recommend to use NumberFormat instead of DecimalFormat because it is locale-sensitive

val decFormat = NumberFormat.getInstance() // or getCurrencyInstance()
decFormat.maximumFractionDigits = 3
decFormat.format(priceMin)
decFormat.format(priceMax)