Won't go inside if statemente even when statemente is true. Kotlin - kotlin

Question

I'm trying to make a simple calculator but the equals button doesn't perform as expected, it doesn't do any of the operations even though the if statement is true. This is the code
var value1: Float = 0f
var value2: Float = 0f
var operator: String = "n"
val input = expression.text.toString().trim()
//this is the adding button the subtracting, multiplying, and dividing are basically the exact code
plus.setOnClickListener {
if (input.isNullOrBlank()) {
expression.text = ""
} else {
operator = "sum"
value1 = expression.text.toString().toFloat()
expression.text = ""
}
}
//equals button
equals.setOnClickListener {
val input2 = expression.text.toString().trim()
if (!input2.isNullOrBlank()) {
value2 = expression.text.toString().toFloat()
// this is the textView and it always shows up as n
expression.text = operator
//it never goes in any of these, I don't know if I'm setting it up wrong in the action buttons (add, sub, multi, div)
if (operator == "sum") {
var s = value1 + value2
expression.text = s.toString()
operator = "n"
}
if (operator == "sub") {
var r = value1 - value2
expression.text = r.toString()
operator = "n"
}
if (operator == "div") {
var d = value1 / value2
expression.text = d.toString()
operator = "n"
}
if (operator == "multi") {
var m = value1 * value2
expression.text = m.toString()
operator = "n"
}
}
}
Why is this happening? I don't know if I'm setting up the operator String wrong or if it's something else I'm doing wrong.
I wanted to have it so that if the values aren't imputed than the operator or equals button won't work like on the phone calculator

Answer 1

val input = expression.text.toString().trim()
Here you capture the content of that edittext at view setup phase. It's likely empty at this point.
Then, in the click listener you have conditional code for that value:
plus.setOnClickListener {
if (input.isNullOrBlank()) {
expression.text = ""
} else {
operator = "sum"
value1 = expression.text.toString().toFloat()
expression.text = ""
}
}
and the input.isNullOrBlank() condition is always true so the else branch never gets executed.
You likely should read the input (val input = expression.text.toString().trim()) inside the click listener.

Answer 2

This is what I came up with
//operator buttons
plus.setOnClickListener {
if (expression.text.toString().trim().isNullOrBlank()) {
expression.text = ""
} else {
value1 = expression.text.toString().toFloat()
operador = "suma"
expression.text = ""
}
}
the equals button stays the same