currency converter number format

Question

Hello I am making a currency converter, from Indonesian rupiah to 12 other currencies.
In the example below, I would like to obtain:
for 10 RUPIAH ➝ 0.001 eur
for 100 RP ➝ 0.006 eur
for 1000 RP ➝ 0.06 eur
for 100,000 RP ➝ 6 eur
for 1,000,000 RP ➝ 60 eur
for 10,000,000 RP ➝ 600 eur

I made an example of the rupiah to euro. I have a field where I enter a value and the other values automatically update.

My problem is, that in the display tab, it puts values with exponents. I would like to have a number with a maximum of 2 digits after the point. is there a method to get this? Thank you!

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)


        valeurIdr.addTextChangedListener(object : TextWatcher {
            override fun onTextChanged(s: CharSequence, start: Int, before: Int, count: Int) {

                if (s.toString().equals("")) {
                    resultEuro.text=null
                } else {

                    val idr = valeurIdr?.text.toString().toDouble()
                    val euro = 0.000060

                    resultEuro?.setText((idr * euro).toString())
                }


            }

            override fun beforeTextChanged(
                s: CharSequence, start: Int, count: Int, after: Int) {
            }

            override fun afterTextChanged(s: Editable) {
                // TODO Auto-generated method stub
            }
        })


    }
}

The problem

Answer 1

First of all That is mathematically incorrect.

But IF you wanted to 6.000000 = 6.00

fun roundOffDecimal(number: Double): Double? {
    val df = DecimalFormat("#.##")
    df.roundingMode = RoundingMode.CEILING
    return df.format(number).toDouble()
}

Above method with give you the highet value of 2 digits ex: 1.78345 = 1.79