kotlin Generic type function as parameters

Question

i stuck in some problems about the generic type in kotlin. Originally,i want to call the function with the value and the recall-function. So i write that below, but the value only allows me pass a type like string/Int somethings like that. I want to pass a function as parameter in the recall function.

ClassA

ClassA<T>{
var canCancel: Boolean = true
var recallFunction: (() -> T)? = null
var recallFunctionWithValue: ((value: T) -> Unit)? = null
var context: Context? = null
var value: T? = null
var functionPara :( ()->T)? = null
var recallFunctionWithFunction:((()->T) -> Unit)? = null

constructor(context: Context?, canCancel: Boolean, value: T, recallFunctionWithValue: (value: T) -> Unit) {
this.context = context
this.canCancel = canCancel
this.value = value
this.recallFunctionWithValue = recallFunctionWithValue
}
}

ClassB

ClassA(ctx, true,viewModel!!::testRefInside,viewModel!!::testRefOutside).createNativeNetworkDialog()

ViewModel

fun testRefOutside(test: Observable<Any>? ){

}
fun testRefInside():Observable<Any>?{
    return null
}

---

i try to do something like that

var canCancel: Boolean = true
var recallFunction: (() -> T)? = null
var recallFunctionWithValue: ((value: T) -> Unit)? = null
var context: Context? = null
var value: T? = null
var functionPara :( ()->T)? = null
var recallFunctionWithFunction:((()->T) -> Unit)? = null

    constructor(context: Context?, canCancel: Boolean, value: () -> T, recallFunctionWithValue: (value: ()->T) -> Unit) {
    this.context = context
    this.canCancel = canCancel
    this.functionPara = value
    this.recallFunctionWithFunction = recallFunctionWithValue
}

but it shows the syntax error. Can someone help?

Syntax Error

Error

Error2

Error show in this place only RYEasyDialog means ClassA

---

It works!! now

  var recallFunctionWithFunction:((value: T) -> Unit)? = null
    constructor(context: Context?, canCancel: Boolean, value: () -> T, recallFunctionWithValue: (value: T) -> Unit) {
    this.context = context
    this.canCancel = canCancel
    this.functionPara = value
    this.recallFunctionWithFunction = recallFunctionWithValue

}

8/6 Updated Vararg problems

I am doing something in advanced. I just post it in completed code. If i don't use vararg, the

EasyDialog<Observable<Any>,LiveData<Boolean>>(ctx, true,viewModel!!::callGetTeammateListAPITEST,recallFunctionWithFunction = viewModel!!::callMultipleAPI).createNativeNetworkDialog2()

without casting as ((Observable<Any>)->LiveData<Boolean>) .but the callMuipleApi receives vararg parameter, i have to cast it into as ((Observable)->LiveData) but i it doesn't show any error but the function callmutipleapi and callgetteammateslist in not called. can anyone help?

ViewModel

fun callMultipleAPI( vararg  observable: Observable<Any>):LiveData<Boolean>{
    if(progressDialogData==null){
        progressDialogData= MutableLiveData()
    }
    progressDialogData?.setValue(true)
    repo.callMultipleAPI<Any>(*observable, observer = RYEasyObserver(object : RyObserverSingleStatusListener<List<Any>> {
        override fun onNext(g: List<Any>) {
            Log.d("test",g.toString())
            for(model in g){
                when(model){
                    is GetTeammateListModel ->{setCallGetTeammateListResponse(model)}
                    is GetTeamListModel ->{setCallGetTeamListResponse(model)}
                    is GetMessageSumModel->{setCallGetMessageSumResponse(model)}
                    is GetCallModel->{setCallGetResponse(model)}
                }
            }
            progressDialogData?.setValue(false)
        }


        override fun onError() {
            progressDialogData?.setValue(false)
        }

    },true))
    return progressDialogData!!
}

Fragment

EasyDialog<Observable<Any>,LiveData<Boolean>>(ctx, true,viewModel!!::callGetTeammateListAPITEST,recallFunctionWithFunction = viewModel!!::callMultipleAPI as ((Observable<Any>)->LiveData<Boolean>)).createNativeNetworkDialog2()

EasyDialog

class EasyDialog<T,V> {
var canCancel: Boolean = true
var recallFunction: (() -> T)? = null
var recallFunctionWithValue: ((value: T) -> Unit)? = null
var context: Context? = null
var value: T? = null
var functionPara :(()->T)? = null
var recallFunctionWithFunction:((T) -> V)? = null



    constructor(
    context: Context?, canCancel: Boolean, value: ()->T, recallFunctionWithFunction:  (T) -> V  ){
    this.context = context
    this.canCancel = canCancel
    this.functionPara = value
    this.recallFunctionWithFunction = recallFunctionWithFunction
}
    fun createNativeNetworkDialog2() {
    val builder = AlertDialog.Builder(context)
    if (!canCancel) {
        builder.setCancelable(false)
    } else {
        builder.setNegativeButton(context?.resources?.getString(R.string.gloda_cancel)) { dialogInterface, id -> }
    }
    builder.setMessage(context?.resources?.getString(R.string.global_network_error))
    builder.setPositiveButton(context?.resources?.getString(R.string.global_retry)) { dialog, id ->
        recallFunction?.invoke()
        value?.let { it1 -> recallFunctionWithValue?.invoke(it1) }
        //functionPara?.let { it2->recallFunctionWithFunction?.invoke(it2) }
        functionPara?.let{ functionPara->{ recallFunctionWithFunction?.let {
                recallFunctionWithFunction-> compose<T,V>(recallFunctionWithFunction  ,functionPara).invoke()
        }}}
    }

    val dialog = builder.create()
    dialog.show()
}
    fun <T, V> compose( f: (T) -> V,    g:() -> T ): () -> V {
            return {  f(g()) }
}

Answer 1

The last constructor parameter is

(() -> T) -> Unit

Based on what you pass for the third constructor paramter, T is inferred to be Observable<Any>? . so it is expecting a

(() -> Observable<Any>?) -> Unit

but testRefOutside is

 Observable<Any>? -> Unit

I'm guessing you probably didn't mean to define a third-order function by making the input of your function another function.