Moshi: problem with platform class BigDecimal

Question

I have a class:

@JsonClass(generateAdapter = true)
data class DayAveragePriceModel(
    val asset: Asset,
    val value: BigDecimal
)

where Asset is a custom class I have. I'm trying to use Moshi but I'm getting the following error:

Caused by: java.lang.IllegalArgumentException: Platform class java.math.BigDecimal (with no annotations) requires explicit JsonAdapter to be registered

How can I work around this? I tried with

        return Moshi.Builder()
            .add(KotlinJsonAdapterFactory())
            .add(Object::class.java)
            .build()
    }

but it is crashing.

Thanks a lot in advance!

score 24 · Accepted Answer · answered Mar 04 '19 at 23:23

24

As the exception says, this is a platform type, and you need to use its public API to encode and decode it.

object BigDecimalAdapter {
  @FromJson fun fromJson(string: String) = BigDecimal(string)

  @ToJson fun toJson(value: BigDecimal) = value.toString()
}

return Moshi.Builder()
    .add(BigDecimalAdapter)
    .add(KotlinJsonAdapterFactory())
    .build()

answered Mar 04 '19 at 23:23

Eric Cochran

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I am trying to follow your example to add an adapter for ULong and UByte, but I still get the error after adding their respective adapters to the builder. – JPM Jan 02 '21 at 09:32
Would you please look at my question at https://stackoverflow.com/questions/67605312/how-to-write-an-explicit-moshi-jsonadapter-for-a-livedata-object – Davi May 19 '21 at 15:21
this doesn't seem to work – user2836943 Nov 21 '22 at 00:05
@user2836943 if you open a new question with a reproducible case, i'll take a look, but this code does work. – Eric Cochran Nov 21 '22 at 05:45
sorry, i take back, i made a mistake, its working, thanks – user2836943 Nov 22 '22 at 23:55

Moshi: problem with platform class BigDecimal

1 Answers1