only classes are allowed on the left hand side of a class literal

android generics gson kotlin data-class

Bhuvanesh BS · Sep 25, 2017 · Viewed 13k times · Source

I know a lot of similar questions here in StackOverflow, but nothing solved mine.

I have a generic data class:

  data class ServiceCall<out T>(val result: T?, val exception: String?, val pagination: String?, val stringResult: String?)

I am trying to use like this:

Gson().fromJson(json, ServiceCall<SurveyListModel>::class.java).result

IDE shows error: only classes are allowed on the left hand side of a class literal

How to solve this? Thanks in advance.

Answer

You can't use generics with class, as easily observable here:

List<Int>::class.java

It gives you the same error. To use the generic typ in GSON deserialization, do what is suggested here:

EDIT:

In Kotlin it looks like this:

val type: Type = object : TypeToken<ServiceCall<SurveyListModel>>() {}.type 
Gson().fromJson<ServiceCall<SurveyListModel>>(json, type).result

Here's a small proof of concept, I've written:

 class Token : TypeToken<List<Int>>()
 val x: List<Int> = Gson().fromJson(Gson().toJson(arrayOf(1)), Token().type)
 println(x)