CODEWITHSUNDEEP
genericskotlin
lannyf
lannyf

Reputation: 11025

how to pass a generic typed data to a function taking the generic type

got one question resolved in here 

interface IRemoteData<T> {
    fun getJsonPOJO() : T?
}

class RemoteData<T>(response: Response<ResponseBody>, pojoClassType: Class<T>) : IRemoteData<T> {

    private var mData: T? = null
    override fun getJsonPOJO(): T? {
        return mData
    }
}

now after created a RemoteData instance

val remoteData = RemoteData(response, POJOClazz::class.java)

get another error when passing this remoteData to a function which takes a generic type as well

handler.onRemoteDataReady(remoteData)
//<===  got Type mismatch: inferred type is RemoteData<out Class<T>> but IRemoteData<T>? was expected

the function is defined with in a interface taking d: T?

interface IHandler<T> {   
    fun onRemoteDataReady(data :T?)
}

the handler instance:

class ResponseHandler(val action: Action) : BaseHandler(action), IHandler<IRemoteData> {
    init {
        mAction?.preAction(this)
    }
    override fun onRemoteDataReady(data: IRemoteData?) {
        val responseRecieved = data?.getJsonPOJO()
        .......
   }
}

Upvotes: 0

Views: 46

Answers (1)

NSimon
NSimon

Reputation: 5287

As stated in the comments, the interface IRemoteData needs a generic type.

Here's the working example:

interface IHandler<T> {
    fun onRemoteDataReady(data :T?)
}

class ResponseHandler<T>(val action: Action) : BaseHandler(action), IHandler<IRemoteData<T>> {

    override fun onRemoteDataReady(data: IRemoteData<T>?) {
        val responseReceived = data?.getJsonPOJO()
    }
}

And it's usage:

val remoteData = RemoteData(response, POJOClazz::class.java)
val handler = ResponseHandler<POJOClazz::class.java>(action)
handler.onRemoteDataReady(remoteData)

Remember from the previous answer, your interface IRemoteData needs a type. So when you declare the ResponseHandler class, you need to specify the type as well. A ResponseHandler<String> will implement IRemoteData<String>.

Upvotes: 1

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