cannot apply java lang integer android
val a = result.text.toString()
val b = resultHist1.text.toString()
if(!a.isNullOrEmpty() && !b.isNullOrEmpty() ){
val a = a.toInt()
val b = b.toInt()
calcHist1.text = (a+b).toString()
}
else
{
calcHist1.text = ""
}