Why getting a key value changed it's data type in Kotlin?-CodePudding

So I have class named Bidding.kt, and I have companion object in that class to be passed to the MainActivity.kt class. Also I have a function that returns as int value.

companion object {
    const val bidInputKey = "bidInput"
}

val bidInput = returningBid() //this function returns an int value
val returnIntent = Intent().apply {
    putExtra(bidInputKey, bidInput)
}

In the MainActivity.kt class, when I called the bidInput to be assigned to a new variable and passed it into a class's parameter, it required to be converted to Int (I set the class's parameter data type as Int). I don't understand why it changed the data type and detect it as a String, I declare it as Int on Bidding class.

    class openBid(var input: Int) {
        //doing some stuff here
    }
    val puttingBid = Bidding.bidInputKey
    val addBid = openBid(puttingBid) // I get error in this line because 
                                    // puttingBid is detected as a String, not Int

I can avoid the error by adding .toInt() when declaring puttingBid, but I want to know why the data type is changed by itself.

CodePudding user response：

If you're trying to pass that Int to MainActivity as an extra on the Intent, you need to pull that value out of the extras, same as how you put it in:

val puttingBid = intent.getIntExtra(Bidding.bidInputKey, DEFAULT_VALUE_IF_MISSING)

All bidInputKey is is an identifier string, used to store a value in the Intent and then retrieve it later. There's nothing magical about it that would make it fetch the Int itself or anything! You need to do that yourself.