如何获得枚举改型的价值？

Question

我有一些枚举值，称为Counter

enum class Counter{
    none,
    few,
    many
}

我想通过改型在模型中获取此枚举的价值，所以我创建了一个对象

data class Test(
        var param1: String?,
        var param2: String?,
        var counter: Counter?,
)

但是，当我将这种类似的模型用于Retrofit方法时，尽管服务器的响应为{"param1": "String1", "param2": "String2", "counter": "many"} ，但我仅获得param1和param 2。 {"param1": "String1", "param2": "String2", "counter": "many"}

如何获取计数器的值，不要在模型var counter: String? ？

Answer 1

像这样创建你的枚举

enum class Counter{
    @SerializedName("none")
    none("none"),

    @SerializedName("few")
    few("few"),

    @SerializedName("many")
    many("many")
}

Answer 2

您可以使用JsonDeserializer对网络调用进行自定义反序列化。

class TestDeserializer: JsonDeserializer<Test> {

    override fun deserialize(json: JsonElement, typeOfT: Type, context: JsonDeserializationContext): Test {
        val obj = json.asJsonObject

        val param1 = obj.get("param1")?.asString
        val param2 = obj.get("param2")?.asString

        val counter = when(obj.get("counter")?.asString) {
            "none" -> Counter.none
            "few" -> Counter.few
            "many" -> Counter.many
            else -> throw IllegalArgumentException("Counter type unknown.")
        }

        return Test(param1, param2, counter)
    }
}

而且，您在创建Retrofit客户端时只需注册它即可。

val gson = GsonBuilder()
        .registerTypeAdapter(Test::class.java, TestDeserializer())
        .create()

return Retrofit.Builder()
        .baseUrl(BASE_URL)
        .client(client)
        .addConverterFactory(GsonConverterFactory.create(gson))
        .build()