Mamykin Andrey :
How to register custom Json deserializer in Gson?
When I'm register deserializer in java code all works fine, but when I convert Kotlin to Java - deserializer method not called.
Kotlin register code:
val listType: Type = object : TypeToken<List<Advert>>() {}.type
val gson = GsonBuilder()
.registerTypeAdapter(listType, deserializer)
val retrofit = Retrofit.Builder()
.addConverterFactory(GsonConverterFactory.create(gson))
Java code:
Type listType = new TypeToken<List<Advert>>() {}.getType();
Gson gson = new GsonBuilder()
.registerTypeAdapter(listType, deserializer)
Retrofit retrofit = new Retrofit.Builder()
.addConverterFactory(GsonConverterFactory.create(gson))
Deserializer declaration:
class AdvertsDeserializer : JsonDeserializer<List<Advert>> {
override fun deserialize(json: JsonElement?, typeOfT: Type?,
context: JsonDeserializationContext?): List<Advert> {
Method calling
// list is List<Advert>
service.getAdverts()
.subscribe({
list ->
viewState.showAdvertsList(list)
}, {
error ->
error.printStackTrace()
})
As I understand - problem in type of Json object(listType), or what I'm doing wrong?
Miha_x64 :
The problem is that Kotlin compiler sees List like a covariant generic type List<out T> and compiles its instantiations as wildcard types, i. e. List<CharSequence> gets compiled as List<? extends Charsequence>.
The solution is either to use MutableList which is invatiant
object : TypeToken<MutableList<Advert>>() {}.type
or to supperss wildcard generation
object : TypeToken<List<@JvmSuppressWildcards Advert>>() {}.type
More info: Kotlin Generics. Variance
Guess you like
Origin http://10.200.1.11:23101/article/api/json?id=464522&siteId=1