CODEWITHSUNDEEP
kotlingson
Praveen P.
Praveen P.

Reputation: 1106

Type mismatch during Gson deserialize json response with kotlin

I am trying to serialize the json response below, but I am unsure how to do it.

This is the Json my backend returns:

[
  {
    "title": "Dummy section, should not be seen",
    "type": "dummy_test",
    "metadata": []
  },
    {
    "title": "Title1",
    "type": "categories_products",
    "metadata": [
      {
        "id": "1272"
      }
    ]
  },
  {
    "title": "Title2",
    "type": "categories_products",
    "metadata": [
      {
        "id": "996"
      }
    ]
  }
]

This is my ExploreItem class:

data class ExploreItem(
    @SerializedName("metadata") val metadata: List<Metadata> = listOf(),
    @SerializedName("title") val title: String = "",
    @SerializedName("type") val type: String = ""
) {
    enum class ExploreItemType(val value: String) {
        @SerializedName("unknown")
        UNKNOWN("unknown"),

        @SerializedName("other_companies")
        OTHER_COMPANIES("other_companies"),

        @SerializedName("categories_products")
        CATEGORIES_PRODUCTS("categories_products"),

        @SerializedName("popular_categories")
        POPULAR_CATEGORIES("popular_categories")
    }
}

data class Metadata(
    @SerializedName("id") val id: String = ""
)

And now I am trying to serialize it in the repository like this:


Serializer.defaultJsonParser.fromJson(response.body!!.string(),ExploreItem::class.java )

but it doesn't work because it's expecting a list of ExploreItem. How can I rewrite the serializer expression to parse it into a list?

Upvotes: 0

Views: 567

Answers (1)

vincenzopalazzo
vincenzopalazzo

Reputation: 1645

From your error

Type mismatch. Required:List Found:ExploreItem!

Post errors is very important, Gson is telling you that it wants a List and not an object of ExploreItem.

In other words, you are telling to Gson with the call Serializer.defaultJsonParser.fromJson(response.body!!.string(),ExploreItem::class.java )

"Hey Gson, from the string I want an object ExploreItem", and Gson is telling you "Hey my friend, you string start with [ ] for sure it is a list of something and not a single object."

You need to pass in the Serializer.defaultJsonParser.fromJson(response.body!!.string(),List<ExploreItem>::class.java)

P.s: I'm not sure about the Kotlin syntax

Upvotes: 2

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