kotlinlang #squarelibraries

The problem is that it does so for the generated subtype, but not for your interface type. We need a mechanism to automatically add an alias and that can only live inside Dagger

Ayden

07/18/2018, 1:02 PM

Hi guys. I have a question about Retrofit 2 with Moshi. This is the response from the server.

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{
  "status": true,
  "code": null,
  "result": {
    "id": 1,
    "name": "User",
    "email": "<mailto:user@gmail.com|user@gmail.com>",
    "created_at": "2018-07-12 15:25:42",
    "updated_at": "2018-07-12 15:25:42"
  }
}

This is my data class.

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data class Response (
        @Json(name = "status") val status: Boolean?,
        @Json(name = "code") val code: Int?,
        @Json(name = "result") val result: UserResult?
)

data class UserResult (
        @Json(name = "id") val id: Int?,
        @Json(name = "name") val name: String?,
        @Json(name = "email") val email: String?
)

This is my Retrofit

call.enqueue

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call.enqueue(object : Callback<Response> {
    override fun onFailure(call: Call<Response>?, t: Throwable?) {
        ...
    }

    override fun onResponse(call: Call<Response>?, response: Response<Response>) {

        if (response.isSuccessful) {
            val result = response.body()?.result.toString()
            // The result being return is id=1, name=Username, email=username@email.com according to Log.d
            
            // How to extract the user information 
        }

    }
})

May I know how to extract the user information from the response given? I have try

Moshi Custom Type Adapter

and various of method. But I would either get

Conversation error

or wrong result. PS: I am double posting this on different channel because I don't know which channel is appropriate to ask this

eric

07/18/2018, 5:02 PM

The result being return is id=1, name=Username, email=username@email.com according to Log.d

sounds correct. what's the question? what's a "Conversion error?"

Ayden

07/19/2018, 1:13 AM

@eric sorry for the late reply. The

Conversion error

happened when the user is empty. But now one of the issue is I don't know how to extract the json and store it into a variable. 😞

eric

07/19/2018, 4:48 PM

stack trace? if you have a test case with the desired result, i could take a look.

Ayden

07/20/2018, 2:11 AM

@eric I solved it.

Ayden

07/20/2018, 2:11 AM

Thanks.

Ayden

07/20/2018, 2:11 AM

@eric if my OkHttp receive the response from the server, but the callback in

call.enqueue

show null.

Ayden

07/20/2018, 2:11 AM

May I know what is the possible issue?

dave08

07/25/2018, 2:58 PM

How do I get Moshi to parse to nested generic class like :

JsonRpcResponse<List<User>>

07/25/2018, 2:59 PM

there's a factory for parameterized types on

Types

which you can then use to look up an adapter

dave08

07/25/2018, 3:00 PM

For just one level it would be using :

Types.newParameterizedType(JsonRpcResponse::class.java, resultType)

but even though I did the same for the list and passed it as

resultType

I get

Types.newParameterizedType(JsonRpcResponse::class.java, resultType)

dave08

07/25/2018, 3:00 PM

val resultType = Types.newParameterizedType(List::class.java, Type::class.java)

dave08

07/25/2018, 3:01 PM

@jw This is my class:

data class JsonRpcResponse<out R>(val id: Int, val result: R? = null, val error: JsonRpcError? = null, val jsonrpc:String = "2.0")

dave08

07/25/2018, 3:02 PM

Maybe I'm doing this wrong?

07/25/2018, 3:02 PM

looks fine so far

dave08

07/25/2018, 3:03 PM

I get

java.lang.IllegalArgumentException: No JsonAdapter for interface java.lang.reflect.Type (with no annotations)

@jw...

07/25/2018, 3:04 PM

you passed

Type

instead of

User

for the list parameter

dave08

07/25/2018, 3:06 PM

Because it's nested

JsonRpcResponse<List<User>>

, so I can't just pass User to the result parameter of JsonRpcResponse, I need it to be in a List and that gets erased also...

dave08

07/25/2018, 3:07 PM

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val resultType = Types.newParameterizedType(List::class.java, Type::class.java)
val responseType = Types.newParameterizedType(JsonRpcResponse::class.java, resultType)

val response = moshi.adapter<JsonRpcResponse<R>>(responseType).fromJson(stringResponse)!!

07/25/2018, 3:08 PM

in that code, you are passing

Type

instead of

User

as the parameter of the list that is

resultType

eric

07/25/2018, 5:08 PM

https://github.com/square/moshi#parse-json-arrays

dave08

07/26/2018, 5:31 AM

@eric You're right, but I mean there's some (like me...) that don't realize that it's not just for arrays. I think it should be stressed that the problem is with ALL generics and also how to handle nested generics.. So it's Parse Generics and JSON Arrays. Not everybody that will be using the library will be so proficient in these topics, I think.

pnih

07/26/2018, 11:49 AM

There's a problem w/ this:

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@Retention(AnnotationRetention.RUNTIME)
@JsonQualifier
//@Target(AnnotationTarget.FIELD)
annotation class EmptyString

internal class StringAdapter {

    @FromJson @EmptyString
    fun fromJson(reader: JsonReader) = when (reader.peek()) {
        JsonReader.Token.BOOLEAN -> when (reader.nextBoolean()) {
            false -> null // Response was false
            else ->
                throw IllegalStateException("Non-false boolean for @JsonObjectOrFalse field")
        }
        JsonReader.Token.STRING -> ""
        else ->
            throw IllegalStateException("Non-object-non-boolean value for @JsonObjectOrFalse field")
    }

    @ToJson
    fun toJson(writer: JsonWriter, @EmptyString value: String?) {}
}

That this test fails with:

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class JsonParserTest {
    @Test
    fun testEmptyStringParser(){
        val moshi = Moshi.Builder().add(StringAdapter()).add(KotlinJsonAdapterFactory()).build()
        val nullJson = """
            { "name": false }
        """.trimIndent()

        val result = moshi.adapter<TestData>(TestData::class.java).fromJson(nullJson)!!

        assert(TestData("Hello") == result)
    }
}

com.squareup.moshi.JsonDataException: Non-null value 'name' was null at $.name

. Am I missing something?

eric

07/26/2018, 8:28 PM

what does TestData looks like?

eric

07/26/2018, 8:28 PM

does it take a nullable string for name?

eric

07/26/2018, 8:29 PM

cuz the adapter up there returns null for the false value.

☝️ 1

Ayden

08/01/2018, 12:27 PM

Hi guys.

Ayden

08/01/2018, 12:27 PM

I created a Deserialize for Gson.