How to Store Class in a Variable Kotlin - kotlin

Question

i want to store a Class in a variable, the purpose is to check if other variable is an instanceOf the class
Here is My Code :
when (it.itemId) {
R.id.vend_list -> {
replace(R.id.fragmentContainer, vendingList)
id = VendListClass
}
R.id.label -> {
replace(R.id.fragmentContainer, label)
id = LabelClass
}
R.id.home -> {
replace(R.id.fragmentContainer, mainMenu)
id = MainMenuClass
}
R.id.statistic -> {
replace(R.id.fragmentContainer, statistic)
id = StatisticClass
}
else -> {}
}
for(fragment in supportFragmentManager.fragments){
if(fragment !is id){
remove(fragment)
}
}

Answer 1

I don't know your exact requirement. But it probably could be designed in other ways, enum? sealed classes? inheritances?
Anyway, straight to your question, hope this helps:
val listCls = List::class
val strCls = String::class
val listObj = listOf(1,2,3)
println("check listObj and listCls: ${listCls.isInstance(listObj)}")
println("check listObj and strCls: ${strCls.isInstance(listObj)}")
output:
check listObj and listCls: true
check listObj and strCls: false

Answer 2

You can store a class reference in a KClass<*> variable using ::class or in a Class<*> variable using ::class.java
So based on your original code, this is how you could do it
// this has to be a nullable type because of your else option
var id: KClass<*>? = null
when (it.itemId) {
R.id.vend_list -> {
replace(R.id.fragmentContainer, vendingList)
id = VendListClass::class
}
R.id.label -> {
replace(R.id.fragmentContainer, label)
id = LabelClass::class
}
R.id.home -> {
replace(R.id.fragmentContainer, mainMenu)
id = MainMenuClass::class
}
R.id.statistic -> {
replace(R.id.fragmentContainer, statistic)
id = StatisticClass::class
}
else -> {}
}
for(fragment in supportFragmentManager.fragments){
// if the else option from when has to remove all
// fragments, just flip the condition to
// if(id == null || id.isInstance(fragment))
if(id != null && id.isInstance(fragment)){
remove(fragment)
}
}

Answer 3

Thanks #Kent for helping, but I figured out how to solve this in an ineffective way.
Here is my code:
val obj1 = Object1()
val obj2 = Object2()
val obj3 = Object3()
val obj4 = Object4()
var id : SuperObject? = null
when(certainConditions) {
option1 -> id = Object1()
option2 -> id = Object2()
option3 -> id = Object3()
option4 -> id = Object4()
}
val otherObject = Object1()
if(id == otherObject) {
//process logic
}
I'm still looking for the more effective way though.
If anyone found out a better way, please share your answer.