I'm trying to display the numbers on the calculator that are clicked on the screen but the code isn't effective. what should be the amendments required? also, I'm new to Kotlin and Android

Android
1

elow is the snippet of the code for onclick actions that must take place but apparently, it isn’t working!

 #fun buClick(view:View)#
{
    val buSel=view as Button

    var buVal:String=etShow.text.toString()

    when(buSel.id)
    {
        button2.id->
        {
            buVal+="-"+buVal

        }
        button5.id->
        {
            buVal+="7"

        }
        button6.id->
        {
            buVal+="8"

        }
        button7.id->
        {
            buVal+="9"

        }
        button9.id->
        {
            buVal+="4"

        }
        button10.id->
        {
            buVal+="5"

        }
        button11.id->
        {
            buVal+="6"

        }
        button13.id->
        {
            buVal+="1"

        }
        button14.id->
        {
            buVal+="2"

        }
        button15.id->
        {
            buVal+="3"

        }
        button17.id->
        {
            buVal+="0"

        }
        button18.id->
        {
            buVal+="."

        }

    }
    #etShow.setText(buVal)#
}